Make: The Annotated Build-It-Yourself Science Laboratory (2015)
Part III. Biology
Chapter 8. General Biology Equipment
Light Source for a Microscope
Purpose: In order to view objects satisfactorily under a microscope, a light source is needed which is neither too bright nor too weak. The light is usually reflected off a mirror at the base of the microscope and up through the lenses.1
Materials: Six-foot extension cord, light base ($1-3 porcelain fixture from the hardware store), and a small 15- or 25-watt blue bulb.
What to Do: Cut off the socket end of the extension cord. Divide the cord into two wires. Strip the end of the wire so that about ¾ of an inch is exposed on each wire. Connect wires to a screw on the bottom of the porcelain fixture. Screw in your light bulb. The porcelain fixture can be mounted on a block of wood so that the screws are not exposed.
Modern Safety Practice
This is an elementary circuit, but great care is required anytime that you design a circuit that directly uses mains (wall) voltage. A shock from mains voltage is potentially lethal. Make sure never to create a situation where a live wire is exposed such that it could be touched. Read Note 10 in Appendix E for safety practice around exposed wiring.
Given all of that, there’s no harm in buying a desk lamp or building a low-voltage LED-based alternative instead.
Operation of Equipment: Set the bulb near the base of the microscope. Turn the mirror on the microscope so the greatest amount of light is seen through the eyepiece. Now move the light closer or farther away in order to increase or decrease the amount of light. This light base can be used for your low-powered microscope or for any light needed in your laboratory. You can improve the illumination by cutting a hole in a black cardboard box and then placing the box over the bulb.
Water Drop Magnifying Glass
Materials: Nail, soft copper wire.
What to Do: Wrap the wire around the nail and make a loop.
Operation of Equipment: Place a drop of water on the loop. The water is heaped up, or rounded. This acts as a lens and magnifies objects. It has a very short focal length. Place your eye close to the drop. Try this lens out on newspaper print, bits of salt, etc. Try different size loops. You might try other liquids besides water.
Materials: Glass tubing, one-inch piece of rubber tubing, material for a small plug for the tubing.
What to Do: Heat the glass tubing with your alcohol burner. When the glass is soft, pull on both ends. Break the tubing at the desired length. Slip the rubber tubing over the large end of the dropper and seal the open end of the rubber to make a bulb.
Modern Safety Practice
For this and the other glass-working projects in this section, re-read the safety tips for working with glass. See “Modern Safety Practice”.
Purpose: The microscope is used to magnify objects that are too small to be carefully studied by the eye alone. Most viewing is done under very low power. The microscope you will make will magnify up to 25 times, so it is said to be 25 power.
Materials: Two or more double convex lenses (five are ideal) with a focal length of about an inch, wood or cardboard box to make the frame, and a small-size light bulb (7½ or 15 watt).
What to Do: Screw the light bulb into a socket. Build a frame to go over the light bulb which will support the slide. The bulb should be three or four inches under the slide. Place the blank microscope slide on the support. Sprinkle some salt on the slide. Now hold a lens as shown and move it up and down until the salt comes into focus. In order to increase the magnification, hold two lenses together and note how the size of the object seems to increase. Now try three, four, or five lenses. Be sure to hold them so one is resting on the next one.
Operation of Equipment: You will notice that when you use only one lens, your eye may be six or more inches away from the lens and the object is still in focus. As you increase the number of lenses, you seem to shorten the focal length, and your eye must be much closer to the lenses. Any substance that is thicker in the middle and will let light through will serve as a lens. The greater the curve the more powerful the lens. A small round glass bead has a lot of curve and is very powerful. A drop of water even makes a good magnifying lens. The light rays hitting the middle of the lens are slowed up. The rays going through the outside edges are thus going faster than those in the center. The rays bend, and it is this bending that causes magnification.
Can You Work Like a Scientist?
1. Place a drop of water on a blank slide (or any piece of glass). Set the leg of a fly in the center of the drop and cover it with a cover glass or another slide. Can you see hairs on the fly’s leg? How does the fly hang onto the ceiling?
2. Try the same with the leg of a bee. You may not need to use water and a cover glass, but they are helpful. Can you see pouches on the bee’s leg? What does the bee use these for?
3. Look at bits of sugar and salt. Is there a difference between the two?
4. Make a set of slides. Hold the parts of insects down on the glass slide with Scotch tape. To make a permanent slide, glue the cover glass to the slide with clear Karo Syrup or gelatin.
5. Place a whole fly on the slide. Look carefully at the eye of the fly. Can you see many little checks or holes? Each one of these is an eye.
6. Put a drop of silver nitrate on a strand of copper wire. You will see a beautiful crystal tree grow on your slide. Silver nitrate is available at the drugstore.2 Be careful. It stains skin or clothes.
7. Can you use two lenses and make a compound microscope?
Purpose: To make a microscope very similar to the first microscope ever invented: a water drop microscope used by Leeuwenhoek about 300 years ago. Leeuwenhoek used a drop of water for a lens. Your microscope will use a glass lens which will be superior. It will magnify up to 160 power.
Materials: Glass rod or tubing, piece of spring brass or iron, three machine screws and nuts about an inch long, and some quick-drying cement.3
What to Do: Heat about a one-inch area of the glass tubing over your alcohol burner. When the glass becomes soft, remove the tubing from the flame and pull both ends of the tubing to stretch the glass (see Part I). Break the thin glass filament about six inches long. Then slowly feed this filament into the flame from above. A thin bead will form. The bead should be not more than 1/16” in diameter. Experiment with different sizes. Break the bead so that it has a tail about an inch long. This is your lens. Drill a hole just smaller than the bead in the center of the spring brass. Cement the bead to the bottom of the brass. Build the rest of the microscope as shown. Your major focusing is done by moving the stage. Tighten the stage by tightening the nuts. Your fine focusing is done with the focusing screw attached to the spring brass.
Read Note 4 in Appendix E about working with hot glass.
Be very careful about touching the heated glass tubing. Glass keeps its heat for a long period of time and can burn your fingers badly.
Operation of Equipment: Place a glass slide on your stage and adjust the stage so you can see the object on your slide. The lens has a very short focal length so you must bring your eye close to the lens. Try salt crystals for your first attempt as these are easy to view. After you sight your object, slowly turn the nut on your fine adjustment. For a light source, either bounce light from a bulb off your mirror and through the slide or place your viewing light directly under the stage for sub-stage lighting.
Can You Work Like a Scientist?
1. This microscope requires care in making. You may have to make many beads before you find one that satisfies you. Patience is the mark of a scientist. Can you think of a way to figure the magnification power of your lens? The power of a lens generally can be figured by dividing the diameter of the lens (in fractions of an inch) into the number ten. If the diameter of your lens is 1/16 inch, how powerful is your microscope?
2. How powerful would your microscope be if the diameter of the lens is ⅛”?
Purpose: A bacteria garden is used to grow or culture various strains of bacteria and molds.
Materials: Ideally, you should have about six glass Petri dishes with lids. Glass castors (the type used under legs of furniture) can be substituted. Another substitute for a Petri dish is a regular bowl.4 The bowl or castor can then be covered with a glass plate or Saran Wrap. You will also need several half-pint bottles or light bulbs with their insides removed. Some agar-agar is desirable. It can be purchased at many drugstores.5
What to Do: Get a can of beef broth from the grocery store. Thin the beef broth with about one quart of water. Add about three tablespoons of agar-agar to the broth. Pour the mixture into the small bottles or light bulbs. Do not fill the bottles more than two-thirds full. Plug the bottles with a wad of cotton and then cover these cotton plugs with pieces of paper toweling and fasten with a rubber band. In order to sterilize the mixture, steam the bottles for about 30 minutes in a pressure cooker.
Plain jello or gelatin can be substituted for the agar-agar and beef broth mixture.
In order to sterilize the Petri dishes or castors, scrub and dry the dishes. Wrap each dish in a piece of paper towel and then wrap about three dishes together with aluminum foil. Place the dishes in an oven that has been heated to a temperature of about 400 °F. Leave the wrapped dishes in the oven for about one hour. Let the dishes cool completely before opening the oven door.
When you are ready to use the dishes and the agar-agar, melt the agar-agar mixture slowly by placing the bottle in hot, but not boiling water. Care has to be taken when you pour the culture mixture into the Petri dishes. The neck of the bottle probably has bacteria on it. Therefore, you should pass the neck of the bottle through the flame of an alcohol burner after you remove the plug. Then remove the lid to the Petri dish and pour the mixture into the dish. If you are filling several dishes follow a certain pattern. Remove the stopper, place the neck of the bottle in the flame, lift the lid, pour the mixture, and cover the dish. Be sure to plug the bottle as soon as you are finished.
Operation of Equipment: Bacteria exist almost everywhere. In order to start a culture, remove the lid of the dish and touch the suspected object to the gelatin. Replace the lid immediately.
1. Most cultures are harmless. However, some bacteria can be harmful. Therefore, when you wish to clean out an old culture from a dish, place the dish in the pressure cooker for about 30 minutes. This should kill any bacteria. Remove the lid only after you have killed the bacteria.
2. Don’t touch hot Petri dishes. Glass holds heat for quite a period of time.
3. Be careful when you are working with the flame from the alcohol burner.
Modern Safety Practice
Review Note 3 in Appendix E about working with fire.
Can You Work Like a Scientist?
1. Do bacteria grow better in daylight or darkness?
2. What effect does temperature have on bacteria growth?
3. Do all forms of bacteria grow at the same rate?
4. What effect does humidity have on the growth of bacteria?
5. Try bacteria from fingernails, air, chewing gum, mouth, comb, shoes, etc.
Purpose: The micrograph is used for group viewing or making drawings of objects viewed through a microscope. The micrograph uses the principle of the microprojector and therefore the sketches made are quite accurate in all details.
Materials: Microscope with a sub-stage light, wooden box and stand, and a piece of frosted glass. Type B requires only a chemistry flask of the proper size to fit over the eyepiece of the microscope, a piece of translucent plastic (such as the sheet that covers a stencil), and a rubber band.
What to Do: Type A is simply a wooden box mounted on legs. A hole is cut in the bottom of the box so that the box will fit over the eyepiece of the microscope. A hole is cut in the top of the box and a piece of frosted glass is used to cover the hole. This is the viewing screen.
Type B is much easier to make. It requires a 250 ml flask. The neck of the flask should just fit over the eyepiece of the microscope.
A piece of frosted (translucent) plastic covers the flat bottom of the flask. This plastic is held in place by a rubber band. The bottom of the flask forms the drawing table.
Operation of Equipment: Place your micrograph over the eyepiece of the microscope. Plug in your sub-stage light. (If you do not have a sub-stage light, use the light from a slide projector. This light can be reflected off the mirror and through the lens system.) Place the slide containing the object to be drawn on the stage. The light shining up through the slide and the lens system strikes the frosted glass plate or plastic. This image can be focused by turning the focusing knob on the microscope. Place a sheet of thin white paper over this viewing screen. You should be able to see the object to be drawn through the paper. The drawings can be made with pencil, charcoal, water colors, crayons, or other art medium. You should use the micrograph in a darkened room.6
Can You Work Like a Scientist?
1. Can you make drawings and compare the legs of various insects such as the bee, fly, grasshopper, and butterfly? Your drawings make a good permanent record.
2. What insects have compound eyes?
3. Can you compare the mouth parts of various insects? How do insects and spiders bite?
4. Can you make drawings of live insects? You can hold the insects down on the slide by using Scotch tape.
Polarized Light Filters
Purpose: Polarizing filters on a microscope are used to strain out certain light rays. Substances can then be examined under this polarized, or directed, light for their optical properties.
Materials: Lenses from a pair of polaroid sunglasses or a small 2 × 2” polaroid filter,7 and any kind of compound microscope.
What to Do: Remove the lowest power eyepiece on the scope. Place the barrel of the eyepiece on the polaroid filter or lens. Trace around the outside of the barrel and then cut the circle out of the filter. The circle should be cut so that it will fit tightly in the barrel at the bottom of the eyepiece.
A second filter can be installed on the microscope or can just be held in position while the microscope is in use (see “Operation of Equipment,” below). If you wish to install a second filter permanently, cut out a small circle from the polaroid material and glue over the large hole in the rotating light aperture disc below the stage of the microscope.
Operation of Equipment: In order to understand how to use your polarizing filters with your microscope, it is necessary to understand how polarizing filters work. There are many theories about how light travels.8 One of the most widely accepted is that light travels in a wave motion similar to waves made in water by the dropping of a stone. These waves travel9 in all directions, some of which are vertical and some horizontal. Most of the waves are neither vertical nor horizontal, but travel at many different angles through the air.
The polarizing filter consists of a thin layer of tiny needlelike crystals of herapathite (iodoquinine sulfate). These needlelike crystals are lined up parallel to each other so they all face in the same direction. The crystals are then enclosed for protection between two transparent plates. Only light rays that vibrate in the same direction as the crystals face on the filter can pass through the filter. All other light rays are screened out.
If two such filters are used, light rays will pass through both if both are turned so the crystals are pointed in the same direction. If we turn or rotate one of the filters, we screen out more and more of the light rays. When the two filters are crossed, all the rays are screened out.
A transparent object placed between the polarizers causes an unusual effect. Instead of being able to screen out all the light rays completely, light seems to be transmitted through the material. Some materials, such as crystals, allow colored light rays to come through. The colors are not a property of the crystal but depend on the thickness of the crystal and the material the crystal is made of as well as the position to which the rotating polaroid filter is turned.
Can You Work Like a Scientist?
1. Look through one piece of a polaroid filter toward the light. Is the light as bright? Part of the light has been polarized.
2. Turn one filter while you hold another filter steady. Can you explain what happens?
3. Place the two filters in the path of light from a flashlight or slide projector. Can you explain what happens to the light cast on the wall as you turn one of the filters?
4. Cross several strips of Scotch tape on a blank microscope slide and place the slide under your microscope. Use either the polarizer you have glued on the disc under the stage, or hold a filter between the sub-stage light and the stage. As you look through it, rotate the eyepiece containing a second filter. The light should polarize the slide containing the Scotch tape strips into beautiful colors.
5. Remove the bottom polarizer (if this is fastened to the disc, turn the disc). Catch a goldfish in your hand and place the head of the goldfish in a wet handkerchief.10 Lay the tail of the goldfish on a blank microscope slide. Examine the tail of the goldfish under low power. You should see the blood circulating through the tail. Add the bottom polarizer. Now rotate the eyepiece. Does the tail of the goldfish polarize?
6. You can grow and polarize crystals under the microscope. Place a few (two or three) acetaminophen crystals on a blank slide.11 Heat the crystals with a match. When the crystals melt, cover them with a cover glass. This spreads the acetaminophen out into a very thin solution. If any carbon from the match gets on the bottom of the slide, wipe this off with a cloth. As the solution starts to cool, it crystallizes. You should see crystals suddenly form and shoot across the slide.
7. Melt the crystal on this slide again with a match. Place the slide under low power and use both polarizers. As the crystal starts to cool again, needlelike crystals will move across your field. Turn your eyepiece as you watch the crystals grow. Can you explain the unbelievable color patterns? Could you melt the crystals again and get the same pattern?
8. What effect does pressure have on the speed the crystals form and move across the screen? Press on the cover glass if the crystals haven’t started to grow. Does this added pressure start the reaction?
Purpose: Cultures are started and maintained in order to have a continuous supply of one-celled and multi-celled plants and animals.12 Observations and experimentations with these simple living things enables us to learn much that will also apply to the higher forms of plants and animals.
Materials: Eyedropper, jars with lids, and food material (hay, lettuce, oat or wheat kernels).
What to Do: Cultures are very easy to start and maintain providing you think of this microscopic life in much the same manner as a civilization of human beings. Human beings cannot stand chlorine in their atmosphere. Micro-organisms cannot stand chlorine in their atmosphere and their atmosphere is the water in which they live.
In order to start a culture, get several quarts of water that do not contain chlorine. Pond water, rain water, river water, or water found in a mud puddle will all support a microscopic civilization. Pour the water into several bottles.
Life needs food. The simplest food material is bits of lettuce. Break bits of lettuce into several of the bottles.
If you are going to try hay, wheat, or oats as a food material, boil these food materials first. This softens the material and makes it easier for micro-organisms to start. You may use any of these food materials in the same way as you used the lettuce. Cover the jars and let the jars stand for about a week.
Operation of Equipment: After about a week examine your cultures by placing a drop of the culture on a blank microscope slide. Examine the drop under the low power of your microscope. You should see small bits of life swimming around. This civilization will continue to grow. As these small animals13 mature and reproduce, the numbers will increase to a point where the food material and oxygen in the water will not support all of the life. To avoid this, divide your culture every week or ten days. Place a few eyedroppers of life into a jar containing new water and food material. In this way you will have a continuous supply of micro-organisms on which to experiment.
Figure 8-1. Culturing microbes
Can You Work Like a Scientist?
1. Can you separate certain micro-animals from the others and try to start a pure culture from just one or two organisms of the same kind?
2. What effect does light have on the growing of a culture?
3. Will protozoa (one-celled animals)14 grow in liquids other than water?
4. What effect does an electrical current in the water have on protozoa such as paramecium?
5. What effect does temperature have on the rate of growth of a culture? Does each kind of micro-organism have its favorite temperature?
6. What micro-organisms feed on other micro-organisms?
Figure 8-2. Microbiology cultures
Growing Brine Shrimp
Purpose: Brine shrimp are large-size members of the microscopic world. They are easy to hatch and raise and make ideal subjects for experimentation. The eggs can adapt to extreme temperature changes.
Materials: Sauce dish or half-pint jar, non-iodized table salt, and brine shrimp eggs. These eggs may be purchased at some pet stores.15
What to Do: Pour one cup of water into the sauce dish or jar. Let the water warm up to room temperature. Mix one teaspoonful of non-iodized table salt into the water. Draw a circle about the size of a dime on a paper. Fill the circle with brine shrimp eggs and then place the eggs in the salt water. They should start hatching after 24 hours. The shrimp should be fed a very small pinch of oatmeal flakes once a week, or a grain or two of dried baking yeast each day. Be careful not to overfeed, or your colony will die off.
Can You Work Like a Scientist?
1. Place a drop of water containing the brine shrimp on a blank microscope slide. Observe under the microscope, microprojector, or magnifying glass. If the brine shrimp grow too large to go through the opening of the eyedropper, remove the bulb from the eyedropper and place it on the other end of the dropper so that you can use the large opening.
2. When some of the brine shrimp grow larger, select pairs and place them in separate containers (medicine vials). If you selected a male and female, eggs should be laid in the vial. Can you keep a record of the life cycle of a pair of shrimp?
3. How fast does a brine shrimp grow? Hatch an egg inside an eyedropper using a very small amount of water. Place the brine shrimp on a glass slide each day and observe with a microscope or microprojector. In order to avoid losing the brine shrimp, use a well slide and then suck the water up with an eyedropper when you have finished. You can make a well slide by gluing a round paper reinforcement ring to the slide.16
4. What effect does temperature have on the hatching rate of the eggs? Try some water at 100°, 90°, 80°, 70°, 60°, 50°, 40°, and at almost freezing temperature.
5. What effect does chlorine in water have on brine shrimp? Try hatching shrimp in tap water containing chlorine. Place a drop of Clorox in a drop of water containing brine shrimp. Observe the effect under the microscope.
6. Try different concentrations of salt. What effect does the salinity of the water have on the hatching rate of brine shrimp? Use a hydrometer to measure the salt concentration in the water.
7. Can a brine shrimp be conditioned gradually to fresh water?
8. Will brine shrimp hatch in fresh water?
9. What percentage of the eggs hatch normally? What conditions affect the hatching of the eggs?
10.How hardy are brine shrimp eggs? Place some eggs in the oven for a short period of time. Keep a graph of the number that hatch after exposure to such unusual temperature conditions.
11.What percentage of the eggs will hatch if the eggs are frozen and then thawed? Find the temperature range the eggs can stand.
12.What effect has light on the percentage of shrimp that hatch? Place some in a darkened area and another in full light.
13.Will brine shrimp regenerate body parts? Remove a leg and then observe if the shrimp can regenerate the leg.
14.What effect has electricity on brine shrimp? Attach two wires to a battery. Place the end of the wire into a small container of brine shrimp. When the electricity passes through the salt water, are the brine shrimp attracted to either wire (pole)?
15.What is the effect of different foods on the growth of brine shrimp? Try other grains as well as foods you think the shrimp might eat. Compare the size and number of shrimp in each container by observing the life under magnification. The number of shrimp observed in one minute moving through the field of the microscope or microprojector will give you an average number for that container. You can compare the containers with their different foods in this way.
16.What do brine shrimp breathe? Fill one bottle and seal the top so no oxygen from the air can enter. As a control, remove the lid from another bottle.
17.What effect do various protozoa have on brine shrimp? Place a brine shrimp into a drop of protozoa culture and observe.
18.What effect does a hydra have on a brine shrimp? Place a shrimp into a large drop of water containing a hydra. Hydra are similar to salt water jellyfish and contain stinging cells. They will sting a shrimp to death and then eat it. This sometimes can be observed through the microscope or microprojector.
19.Can brine shrimp see?
20.What water pressure do brine shrimp prefer? Use a piece of glass tubing or a test tube. If you use glass tubing, plug up the bottom end or seal it in the flame of an alcohol burner. Place the shrimp in the tubing or test tube. Observe at what depth most of the shrimp collect. Glass tubing filled with water is ideal for this experiment as the pressure from the top of the tubing increases tremendously with the depth of the water.
21.What effect does wave action have on the hatching of brine shrimp eggs? Stir one container regularly. Use as a control a container in which the eggs are not stirred.
22.Will brine shrimp hatch if you use iodized salt instead of non-iodized salt?
23.Will brine shrimp continue to live if placed in a solution containing iodized salt after they have hatched in a solution containing non-iodized salt?
24.Do brine shrimp molt or shed their skin?
25.If the water in your brine shrimp dish evaporates, does the salt evaporate too? If not, does the salinity (salt content) of the water change? If you wish to control this change in salinity, mark the level of the water in your container. Replace the water that evaporates with rain or tap water.
26.Can you observe and record the embryology of the brine shrimp? Place the eggs in a shallow glass dish under the microscope or microprojector. Observe the progress of the eggs every hour. Here are some things to look for:
a. Are the eggs completely round, or do they have a dent on one side?
b. Do the eggs seem to swell after the first hour?
c. How long is it before the eggs start to split open?
d. How do the shrimp get out of their eggs? Are they regular adults at first or are they covered with a thin membrane? What is a nauplius?
e. Can you locate a red spot? Is this the eye?
f. How do the shrimp get out of their transparent case? Can you observe this?
g. How many legs do the brine shrimp have? What are the other body parts? Can you compare the body parts with insects and spiders?
Microscope Slide Making
1. Water Drop Slide: Place the object such as a leg of a bee on a blank slide. Place about one drop of water on the object. Lower a cover glass over the water drop and the object. The drop spreads out under the glass and forms a strong seal. Water molecules have a strong attraction for glass molecules. When you wish to remove the cover glass from the slide, soak the slide in warm water. Life cultures and many temporary slides can be made in this way.
2. Vaseline Slide: Insert a toothpick into a jar of vaseline. Draw the edge of the toothpick across the slide to form two vaseline walls. Insert the toothpick in vaseline again and then draw the toothpick along both edges of the slide to finish forming a pen of vaseline on the slide. The pen should be about the same size as the cover glass you use. Place a drop of the culture in the center of the vaseline “swimming pool.” Carefully lower a cover glass down on the vaseline pool. The vaseline should form a seal around the edges of the cover glass and completely trap any microscopic life. An advantage to this kind of slide is that the water cannot evaporate. You can trap rapidly moving micro-organisms by placing a few cotton fibers in the pool before you put the drop of water on the slide. The fibers will trap many small creatures after the cover glass is lowered down on the vaseline ring.
3. Scotch Tape Slide: Small insects and spiders such as mites, aphids, and garden spiders can be held in place and examined “Live” under the microscope. The tape is lowered down on the insect or spider. The tape is then fastened to a blank microscope slide. The small animal is free to kick or otherwise move even though part of the animal is stuck to the tape.17
4. Gelatin Slide: A semi-permanent slide can be made by using gelatin as a glue. A small amount of clear jello is mixed up. The object such as an insect leg is placed on the slide. A drop of liquid gelatin is placed on the object. A similar drop is placed on the blank slide. The blank slide is then lowered down on the cover glass containing the object. The two drops flow together forming a perfect seal between the slide and the cover glass. The slide is left in this position in order to give the gelatin time to harden. Excess of gelatin can be cleaned off with warm water.
5. Well Slide: A well slide is a slide with a depression ground into the center of the slide. This well or concavity forms a “swimming pool” for larger microscopic animals such as brine shrimp, daphnia, and planaria. A well slide can be made from a blank slide by punching a hole in the center of a piece of cardboard with a paper punch. The cardboard should be about the same size as a cover glass. The cardboard square is soaked in shellac and then held in position on a blank slide. The shellac not only sticks the cardboard to the slide, it also waterproofs the cardboard. You can make well slides of any thickness by adding extra layers of cardboard. After the drop of water has been placed in the center of such a well slide, a cover glass is used to flatten out and also hold the water still.
A quick substitute for a well slide can be made by sticking two pieces of Scotch tape about a half inch apart across a blank slide. The space between the two strips serves as a well. The well again can be deepened by adding additional layers of tape.
A wick for a well slide can be made by running a piece of string from a medicine vial containing water to the well on the slide. The water will travel from the vial to the well through the string. The vial can be glued to part of the slide. The water supplied through the string wick replaces the water evaporating from the well.
Permanent Microscope Slides
1. Mounting Small Dry Objects: Objects which are thin and do not contain water can be easily mounted without much preparation. The object such as an insect wing is placed in the center of the cover glass. A drop of Canada balsam is placed on the object. Next, a drop of balsam is placed in the center of a blank slide. The slide is turned over and the hanging drop is lowered into the drop on the cover glass. The two drops flow together and remove any air bubbles. The slide is left in place several days. Then xylene is used to remove the excess balsam around the cover glass.
2. Mounting Objects Containing Water: Objects containing water cannot be mounted in the manner just described. The water in the cells evaporates and the object dries up or withers away. Such a specimen needs to have the water gradually removed from the cells (dehydration). This gradual dehydration is done by soaking the object in several mixtures of alcohol and water. Each succeeding mixture should have a higher proportion of alcohol.
The first mixture should contain about 30% alcohol. Mix one ounce of alcohol with each two ounces of water. You can use a baby bottle to accurately measure out the correct amount. The specimen should be left in this weak mixture for about five minutes.
The second mixture should be about 50% alcohol. Mix equal amounts of water and alcohol. Leave the specimen in this solution for five minutes and then transfer the specimen to a third solution containing 70% alcohol (7 parts alcohol and 3 parts water). Again the specimen should soak for about five minutes.
The fourth solution is 90% alcohol. After five minutes, transfer the specimen to a fifth solution which is 100% alcohol. After five minutes in this solution, place the object in turpentine and let the object soak for several hours. This increases the object’s transparency and makes it easier for light to pass through.
The specimen is finally mounted on a slide by using Canada balsam as has already been described.
The small bottles of alcohol can be saved and used over again. Since alcohol evaporates, the bottles should be capped after every use. The alcohol will eventually be weakened by the addition of water removed from various specimens.
3. Mounting Cross-sections: Microscopes have a very limited depth of field. By this we mean that the microscopes will focus on only one level or spot at a time. Thus, an object that is very thick such as a piece of cork or a stem of a plant cannot be viewed satisfactorily because only a small part of the object will come into focus at any one time. Also, light will not travel through thick sections. Thin sections of specimens are sliced on a microtome. The sections are then dehydrated as mentioned above and mounted by using Canada balsam.
4. Stains: Many times it is helpful to stain or dye parts of a specimen. Since some parts of a specimen react differently to a dye than other parts, a stained slide reveals much detail that cannot be detected without a stain.
Common dye such as methylene blue or Congo red as well as such improvised dye as India ink, merthiolate, and iodine can all be used as stains. Usually the specimen is placed in the dye for a few minutes and then the specimen is washed off in water. The specimen is then mounted as previously described.
Purpose: Many objects are too thick to be viewed under the microscope. The microtome enables you to slice thin sections or cross-sections to be mounted on a slide.
Materials: Either a ¼” or ½” bolt and nut (can be any length), paraffin wax, and a single-edge razor blade.
What to Do: Screw the bolt about one fourth of the way into the nut. Prop the bolt up so the opening of the nut is facing up. Place the object to be viewed in the opening in the nut. Heat some paraffin with a candle and drip the melted paraffin into a spoon.18 Then pour the melted paraffin into the hole around your object.
Operation of Equipment: After the paraffin has completely hardened, screw the bolt into the nut. This pushes some of the paraffin out. Try to slice as thin a section as possible. Move the razor blade down along the face of the nut so as to trim off a very thin section. Trim off several such sections until you have a good cross-section of the object to be viewed. Place this thin paraffin section on a blank slide. Heat the slide slightly and the paraffin will melt and stick to the slide. You can try dropping the sections of paraffin into warm water and then bringing the slide up from underneath the floating sections and lifting the sections out of the water onto the slide. The sections will cool and can then be viewed.
Modern Safety Practice
1. Razor blades can cut your skin very easily, so handle them with extreme care.
2. You will be working with open flames; review Note 3 in Appendix E.
Can You Work Like a Scientist?
1. Use the microtome with leaves of lettuce.
2. Can you see the cells in an onion?
3. Try other vegetables. Which ones work the best?
4. Try stems of various plants.
5. Take cross-sections of tissue of animals. Try different meats.
Purpose: A microtome is used to slice very thin cross-sections of objects so they may be mounted and viewed under the microscope. The microtome described here is capable of producing very thin cross-sections for both viewing and slide-making.
Materials: Two short pieces of copper or steel tubing about a half inch in diameter and about two inches in length, a three-eighths-inch bolt and nut about three inches in length, two small pieces of plastic or two microscope slides, wood for the frame, and a sharp razor blade.
What to Do: Screw the base and upright together. A hole should be drilled in the upright large enough for one of the pieces of metal tubing to slide through while resting on the base. Place the tubing in position. Cut two side support pieces and notch them so that the nut can fit in the slot. Nail the side support pieces alongside the tubing. The nut is placed in the slot and the bolt is screwed through the nut and the tubing. Plastic strips or microscope slides are glued on the back side of the upright as shown.
Operation of Equipment: Place the object to be sliced (such as a stem of a plant) in the extra metal tubing. Pour melted paraffin around the material. Allow the wax to cool completely. After the wax has cooled, push the wax plug out of the tubing and insert the plug into the microtome cylinder. Then, when you wish to slice off a cross-section, screw the bolt through the nut and against the wax plug. The plug can be gently pushed forward until a thin piece sticks out beyond the plastic or glass-cutting surfaces. The wax can be sliced off neatly with a razor blade. The slice should be allowed to drop into a pan of warm water. The slice will float on the surface. As the wax starts to melt, bring the slide up underneath the section and lift up carefully.
If you wish to mount the specimen, place a small drop of balsam on the blank slide. Place a drop on the cover glass as well. The object is held to the slide by the balsam. Turn the slide over and slowly lower the slide and object down on the cover glass. When the two surfaces of balsam meet, they will flow together because of the attraction the like molecules have for each other. You should not have any air bubbles trapped between the slide and cover glass. Allow the slide to dry for several days. Excess balsam can be cleaned off by using xylene, which is a thinner for balsam.
Can You Work Like a Scientist?
1. Can you mark the head of the bolt so that you can accurately measure the thickness of the cross-sections you cut? If the bolt moved a sixteenth of an inch during one complete turn, how far would it move if you turned the bolt only a quarter turn?
Purpose: An animal maze is used to test the intelligence and learning rate of small animals, such as rats, hamsters, etc.
Materials: Two pieces of 1” × 8” wood about 8 feet long, other short wood pieces to make partitions as shown.
What to Do: Cut the boards in half. Make a 4’ × 4’ fence as shown. Nail various short pieces of wood together to form the inside chambers. You can design your own pattern.
Operation of Equipment: You can use a table or the floor for the base or bottom of the maze. Set down the fence and then place the inside chambers into the position you wish.
Rats, hamsters, etc. need a reason for learning. Don’t feed your test animal for about two days. Then place the food at one end of your maze and the animal at the other end. Time the progress of the rat to the food. Also record the number of wrong turns. Try this test twice a day. Reward the animal with food or water. Give the animal no other food or water.19
Can You Work Like a Scientist?
1. Is a rat or a hamster more intelligent?
2. Does the female learn more quickly than the male?
3. Is the desire to care for her young a stronger motivation for a female than food? Than water?20
4. Is learning passed on to the young?
5. Do animals learn faster with a reward or a punishment as a stimulus? Is fear contagious?21
6. Can odor or scent help the animal find his reward?
7. Can the animal relearn a changed pattern more easily? (Move the chambers.)
8. How long does an animal retain learning?
9. What effect has light upon the learning rate?
10.You can make a turtle maze by making a raised platform. The walkways should be about three inches wide and about a foot above the table. A bowl of water serves as a good reward. If you make the walkways out of metal, you can heat the bottom of the metal to get the turtle to move.22
Purpose: The insect net is used to collect insects and trap them until they can be placed in small bottles to be studied.
Materials: Round handle (broom handle or dowel), heavy wire (coat hanger wire could be used), and cheesecloth or lightweight curtain material for netting.23
What to Do: Bend the wire into a circle, leaving about three or four inches of wire sticking out so the wire can be attached to the handle. Fold the end of the cloth over the wire and stitch with a needle and thread. Attach the wire to the handle with tape. Gather the net together at the bottom.
Operation of Equipment: Insect nets are used to catch more than just butterflies. In fact, most insects caught are not flying and are not even seen. With the net make several passes at the bushes. You are bound to collect, along with a few leaves, many insects you do not normally see. Close the net off with your hand and then slowly reach in with a small vial and collect the insects of particular interest. You may place the insects in a killing jar if you wish to dissect them for study under your microscope or to mount them for your collection. The insects can be studied with a hand lens through the vial and released if not wanted.
Purpose: The gas chamber is used on insects in order to preserve the insects in a life-like position.
Materials: Bottle with lid, cotton, liquid that evaporates rapidly and gives off strong gas fumes (fingernail polish remover, or carbon tetrachloride24).
What to Do: Dip the cotton into the liquid. Drop the cotton into the jar. Tighten the lid so the fumes can’t escape. In order to use the jar, remove the lid and drop the insect or insects into the jar. Tighten the lid, and observe the results.
Can You Work Like a Scientist?
1. Are all kinds of insects affected by this gas chamber?
2. What gases kill insects? Will the odor of perfume kill?
Modern Safety Practice
1. Read through Note 17 in Appendix E about safety around chemicals.
2. As you will be storing (a small amount of) toxic material in this jar, it is your obligation to label it clearly: “KILLING JAR (POISON).” Do you understand why you should never smell chemicals to identify them?
Insect Mounting Box
Purpose: A mounting box is used to preserve and display insects.
Materials: Cigar box, paraffin, and Saran Wrap.
What to Do: For the mounting material in the bottom of the box use melted wax (paraffin) or a piece of styrofoam. If you use paraffin, melt the wax in a can over a burner and pour it into the box to a depth of about half an inch. Mount the insects with pins pushed into the wax or styrofoam. After you fill a box with a particular type of insect (such as moths), cover the box with Saran Wrap. This will allow you to study your collection, and yet the insects will be protected. If you wish to keep it intact over a period of time, drop in several mothballs before covering the box.
Quick Freeze Chamber
Purpose: This chamber produces extremely cold temperatures. The chamber is used for carrying out experiments to determine the effects of extreme cold on plants and animals.
Materials: Coffee can or pyrex beaker, rubbing alcohol or duplicator fluid, and two pounds of dry ice. Dry ice is frozen carbon dioxide gas. It costs about $1-2 a pound and is available at ice cream stores, refrigeration plants, and sometimes in school cafeterias.25
What to Do: Put dry ice into the container. Don’t touch the dry ice directly, but instead use a cloth to pick up the pieces. Dry ice can burn the skin.26 Pour the alcohol over the dry ice. Do not place fingers inside the container. Do not touch the outside of the container. The extreme cold will freeze your fingers in a few seconds. Use tweezers to put materials in and out of the can.
Modern Safety Practice
1. Dry ice can cause severe frostbite injuries. Handle only briefly, using oven mitts or a towel to protect your hands. See Note 14 in Appendix E for more information. Alcohol at the temperature of dry ice is also very hazardous. If it is spilled on someone’s skin or clothing, they could be severely injured.
2. Alcohol vapor is flammable. Keep sources of spark and flame away, and have a type ABC fire extinguisher handy.
Can You Work Like a Scientist?
1. Place a few drops of mercury in a test tube and lower into the mixture. What happens to the mercury? How low does the temperature get? Mercury freezes at -38 °F.27
2. Place a frankfurter in the mixture. Try plant leaves, rubber, etc. Try hitting the rubber with a hammer. Then throw the frankfurter to the floor.28
3. Will cultures stay alive at these temperatures?
4. If you placed a goldfish in the tank, could it be revived?
5. What effect does extreme cold have on insects? Will seeds germinate if exposed to extreme cold?
6. What liquids will freeze in the chamber? Use test tubes.
7. Will a turtle survive a quick freeze?29
Purpose: The chest cavity shows how your stomach muscles aid you in breathing. It also shows an effect of air pressure.
Materials: Gallon jug, glass or copper tubing, one- or two-hole rubber stopper, two balloons for lungs, and a large piece of rubber to stretch over the bottom of the jug.
What to Do: Cut off the bottom of the jug with the bottle cutter (“Bottle Cutter”). Be sure to smooth the bottom of the jug with emery paper under water. The easiest way to make the chest cavity is to bend two pieces of glass tubing (“Bending Glass Tubing”). Fasten a balloon on the end of each piece with tape or a rubber band. Stick the ends of the glass tubing into the holes of a two-hole rubber stopper. Put the stopper in place in the jug and then twist the tubes so the balloons (lungs) are in their proper places. Now cut open a large balloon and stretch the rubber across the bottom of the jug. Fasten the rubber with tape or rubber bands. Sheet rubber is stronger and is easier to use for the diaphragm.
Operation of Equipment: The rubber across the bottom of the jug represents your diaphragm (muscles of your abdomen). As you push in and out on the rubber, the balloon lungs inside your chest cavity seem to breathe. You can feel the air move in and out of the rubber stopper. Your breathing is controlled in much the same way by the movement of your diaphragm muscle.
1. Be sure to read all the directions before you use the bottle cutter.
2. Be sure to smooth your jug under water with emery paper.
3. Don’t stretch the balloon too tight on the bottom of the jug or it will split.
Can You Work Like a Scientist?
1. Can you use compressed air and a partial vacuum to explain why the lungs seem to move as the diaphragm moves?
2. Would this chest cavity work on the moon?
3. Can you make the chest cavity snore?
4. What causes snoring? How can you stop a person from snoring?
5. Do fish breathe in this same way?
6. How do birds breathe? Do birds snore?
7. How do animals breathe when they hibernate? Why do animals hibernate?
8. Can you measure the changes in pressure by running a rubber tube from the chest cavity to the vacuum gauge?
9. Can you measure the changes in pressure as your chest cavity moves in and out?
Purpose: The purpose of this chamber is to measure the oxygen consumption of small animals and thus indirectly the metabolism of the animal.
Materials: Milk bottle or wide-mouth quart jar, glass tubing, mason jar adapter lid, one-hole rubber stopper, a wire mesh to enclose the animal, and soda lime or some other material that will absorb carbon dioxide. A tablespoonful is needed for a one-quart container.
What to Do: Place the bottle on its side. Insert soda lime or similar material. Enclose the small animal, such as a white rat, in a wire screen. Tape the screen so the animal can’t move about.30 Measure how much water the glass tubing will hold by using an eyedropper that is marked in cc. Divide the glass tubing into convenient marks for measurement. Place the rat or other small animal into the bottle and insert the stopper and glass tubing. Form a soap bubble at the end of the tubing outside the bottle.
Operation of Equipment: As the rat breathes, he uses oxygen. The rat exhales carbon dioxide but the carbon dioxide is absorbed by the soda lime. Therefore, as the oxygen is used up, the soap bubble travels up the glass tubing. The volume of the space traveled by the soap bubble is equal to the oxygen used. Time this for a one minute period. Multiply this volume (for example, 3/100th of a liter) in liters (about a quart) times 4.8 calories to find the metabolism or rate of burning or using food material.
Can You Work Like a Scientist?
1. If you grow plants in the same bottle, can you produce enough oxygen so that none needs to come from outside the bottle? Would the soap bubble move?
2. Is the metabolism rate always the same? See the effect of fear, different foods, alcohol, tobacco, excitement, etc. on the rate of metabolism.31
3. Is the metabolism rate of all animals alike? Try frogs, etc.
4. Start small plants growing and place some water and a plant in a test tube. Insert a snail and see how long you can keep it alive in a balanced aquarium.
5. Try to make a balanced aquarium with goldfish, water plants, a gallon jug, and a rubber stopper.
6. You can measure the metabolism of very small animals by placing a number of them in the jar. If you use ten animals, you divide the oxygen consumption by ten.
Purpose: The aquarium is used to carry out experiments in the science laboratory, which requires a large container of water. It is also, of course, a place to keep fish and other aquatic life so that a study can be made of their habits, food, and reaction to stimuli.
Materials: Large-mouth gallon jar or gallon jug, nichrome wire bottle cutter.
What to Do: You may use a large gallon jar, just as it is, for your aquarium. A better aquarium, however, can be made by cutting the top off a gallon jug with your nichrome wire bottle cutter. Be sure to smooth the glass edge with wet or dry emery paper.
Operation of Equipment: Fill the bottom of your fish aquarium with about one inch of gravel. Be sure the rocks contain no limestone or acid-forming metals. Slope the gravel so you can place the plants near the back. Plants are necessary to help provide the necessary oxygen. Your pet or feed store will recommend the right types. Fill the aquarium and let the plants root for about a week before adding fish. Since tap water contains chlorine, you must let it stand for at least 48 hours before using it for the aquarium. When you add fish to the tank, set the box from the pet store in the water. The fish then get used to the new temperature. After 15 minutes you can place the fish directly in the tank. Don’t overfeed fish. Never give them more than they can eat in ten minutes. Clean the tank once a week unless it is well balanced with plants.
Can You Work Like a Scientist?
1. Why do you need plants in the water?
2. You can add more oxygen to the tank by pouring the water over and over with a cup. How could you keep the oxygen supply coming in at night?
3. Why is the wider bottom of a gallon jug better than a widemouth gallon jar for an aquarium?
4. What effect does chlorine have on organisms? If you have a culture of paramecium growing, try a drop of chlorine in a spoonful of culture. Examine under the microscope.
5. You can start a saltwater aquarium. Collect salt water from the ocean. This water contains the right amount of minerals. Add your sea life, but make sure you have only a few small specimens. The temperature should be about 65 degrees, so keep the aquarium in a basement or other cool place. Make a mark as to the height of the water. As the water evaporates, the remaining water gets saltier, a condition which will soon kill off the life. In order to keep the salt content the same, add distilled water to fill the aquarium to the mark. Rain water will serve as distilled water. Bits of hamburger or liver serve as food for sea anemones and other life. Hermit crabs help keep the tank clean. You will probably need an aerator.32
Purpose: The classroom or home terrarium allows a student to study animal life in its natural environment.
Materials: Gallon jug, wire screen or glass plate. A second type utilizes a gallon jar with lid, and a wooden stand as shown.33
What to Do: Cut off the top of a gallon jug with your nichrome wire bottle cutter. Smooth with wet or dry emery paper in a bucket. Use a wire screen or a piece of glass plate for a cover. If you want to make the gallon jar terrarium, cut part of the lid off and cover with a wire screen.
Operation of Equipment: Wash some coarse sand and fill the jar to a depth of two inches. Put an equal amount of rich soil on top of the sand. Add some rocks and dead wood. Plant small ferns and bushes. Have some in the shade and some exposed. Water with a squeeze bottle sprinkler. Make this by punching holes in the lid of a squeeze bottle. This woodland terrarium makes a good home for toads, small snakes, young box turtles, some salamanders and lizards.
A semi-aquatic terrarium is suitable for frogs, turtles, and most salamanders. The woodland terrarium will work if the water and land areas are separated. The gallon jar aquarium is best for this. The jar can be tipped at a slight slant, and the water is confined to the bottom of the aquarium. Moisture in both aquariums should be kept quite high.
A desert terrarium is suitable for cactus and desert plants as well as lizards. The sand should be washed and mixed with charcoal and a small amount of lime. Ask your florist about this and about plants.
Turtles eat flies, turtle food, ground meat, bits of fish, lettuce, and other leafy vegetables.
Snakes eat live mice, frogs, earthworms, insects, and they can be coaxed into eating eggs and raw meat. If a snake refuses to eat after a week, it should be released.
Tadpoles eat small bits of lettuce and finely chopped meat. Frogs eat all kinds of insects and worms. Also big frogs eat little frogs. Frogs eat only moving objects, so dangle the worm or insect in front of the frog with tweezers or a string.
Lizards eat all types of insects, live flies, beetles, grasshoppers, and crickets. In the wintertime mealworms will serve as a food supply. Ask a pet store employee how to raise mealworms.
Salamanders in the larval stage eat bits of liver and the yolks of hard-boiled eggs. As adults they eat insects, worms, and bits of raw meat. Most salamanders are active only at night.
Purpose: The dissecting needle is a tool of many purposes. It can be used for making a vaseline ring on a microscope slide. The main purpose of the needle is to help hold tissue during dissections or to remove small parts of insects for further study.
Materials: Common pin, short piece of ¼” wooden dowel (available at any lumber store).
What to Do: If you use a pin, cut off the head. File this tip and then force it into the end of the wood dowel. The end of the pin can then be bent to form any kind of hook needed. You can make a dissecting needle out of a regular needle in the same way described. However, you cannot bend the point, or the needle will snap.
Purpose: The pins are used to hold the skin or tissue in place during a dissection. A pine board is soft and makes a good dissecting board.
Materials: Common pins will serve for dissecting purposes. However, a better substitute is the large round-headed pin used by dressmakers. These are available at most sewing supply counters.
What to Do: Try dissecting an earthworm or a small snake. Remember, do not torture animals. Have a purpose before doing dissecting work.34 An excellent book to consult is The Living Laboratory by James Donald Witherspoon and Rebecca Hutto Witherspoon. This book is published by Doubleday & Company, Inc.
Purpose: The dissecting knife is used in work on animals, insects, etc. It must be very sharp and capable of making a fine incision.
Materials: Single-edge razor blade, ½” wood dowel, small pin or brad.35
What to Do: Cut a slit at the end of the dowel. Insert the razor blade as shown. Drive a pin or brad through the side of the dowel to hold the razor blade in place.
Purpose: An animal cage is used to house animals during periods of observation or experimentation. The animal cage described is easy to make, clean, and store.
Materials: Round candy or cookie tin, half-inch mesh hardware cloth, and materials for a water bottle (baby bottle, one-hole stopper, glass tubing).
What to Do: Bend the hardware cloth into a cylinder. Slip the cylinder of wire into the bottom of the candy tin. The lid of the candy tin fits over the top of the wire cylinder. This lid can be held in place with rubber bands or wire hooks attached to the lid.
A water bottle can be made by bending a piece of glass tubing and inserting it in a rubber stopper. The stopper is then inserted in a bottle containing water. The “drinking fountain” is held in place with rubber bands. The water does not leak out because air is pushing against the glass tubing. The water does fit the glass tubing and forms a bubble of water at the end of the tubing. Animals such as white rats, hamsters, and others lick the water off the end of the tubing.
The animal cage pictured can be stored by removing the top and bottom of the candy container and straightening out the wire cylinder. The wire can be stored flat and thus does not take up needed shelf space.
Problems to Investigate in the Study of Biology
Note: Many of the problems here involve working with animals. Please use appropriate research guidelines. see Note 1 in Appendix E.
Conditions Necessary for Life
1. Are there any places on earth where no living things exist? (P)
2. How far down into the ground would you have to go to find no life? (I)
3. What are the temperature limits for life of different plants and animals? (What are the coldest and warmest temperatures at which they will live?) (I)
4. Is water necessary for all forms of life? (P)
5. What is the minimum water requirement for various plants and animals? (I)
6. Does water contain air? (P)
7. Do fish need air in water in order to live? (P)
8. How much oxygen is used by various forms of plants and animals? (U)
9. Can various plants and animals use pure oxygen? (U)
10.How can we get nitrogen to dissolve in water? (U)
11.How do plants get nitrogen? (I)
12.Can plants live without nitrogen? (I)
13.How much nitrogen is needed by different forms of animals? (U)
14.How much carbon dioxide is used by different plants? (I)
15.Can plants live in pure carbon dioxide? (U)
16.How much food is required by different forms of animal life? How does this compare with the oxygen consumption? (U)
17.What plants need light in order to grow? (P)
18.How much light a day must different forms of plant life have? (I)
19.Will some plants grow in different forms of artificial light? (I)
20.What effect does colored light have on the growth of various plants? (I)
21.How much light is necessary for mushrooms to grow? (I)
22.What animals seek light? (I)
23.What animals avoid light? (I)
24.How are the eyes of various living things alike and unalike? (I)
25.What plants and animals can adjust to changing environments? What plants and animals are unable to adjust? (P)
26.How do the different animals find food? (P)
27.How do the different animals avoid being eaten? (P)
28.How intelligent are various animals? Can you set up a test for them? (I)
29.What effect does the changing of the coloration of an animal have on its ability to live in its environment? (Paint an insect or other animal.) (I)
30.How are some animals able to change their coloration in order to blend in with their environment? (U)
31.What insects cannot be eaten? Experiment with insect-eating animals. (I)
32.Why are some animals colored with warning colors? (Examples: skunk, bumblebee) (P)
33.What animals are protected because of their general appearance? (I)
34.What animals (particularly insects) depend on being mistaken for other animals? (I)
35.How far do various animals move in a day? Can you calculate the speed? (I)
36.Do all animals move? (P)
37.How many different kinds of motions can you observe among animals? (P)
38.Do plants move? (P)
39.What causes movement in plants? (P)
40.Can some plants eat living things? How? (I)
41.What kind of digestive juices are used by various animals to digest their food? (U)
42.How are various animals equipped to get air? (P)
43.Do plants breathe? (P)
44.How much of various food materials is turned into energy? How much food material is not used but excreted? (U)
45.What are the processes of excretion (getting rid of waste materials) in various forms of animals? (U)
46.Can you time the rate of response to various stimuli? (Some common stimuli are heat, pain, electrical current, odor, fear, hunger, light, darkness, noise, moisture, and gravity.) (I)
47.Do the roots of all plants grow toward moisture? (P)
48.Do the leaves of all plants grow toward light? (P)
49.Are plants intelligent? (I)
50.How do various plants and animals reproduce? (P)
51.How closely do the young plants and animals resemble their parents? (P)
52.What plants and animals are not sensitive to stimuli? (I)
53.What do various objects look like under the microscope? (I)
54.How do the cells of various plants and animals compare? (Use a microscope.) (I)
55.Do all living things have cells? (P)
56.Are all the cells of a living thing alike? (I)
57.What do the cells of an onion membrane look like? (Place in a drop of water and cover with a cover glass.) (I)
58.How does staining a material help in locating the parts of a cell? (Use iodine, methylene blue, or ink as a stain on the onion membrane.) (I)
59.What is the cell structure of a geranium or a rhubarb leaf? (I)
60.Do all plants have cell walls? (P)
61.Is the protoplasm of all plant cells alike? (U)
62.Is the nucleus of all plant cells alike? (U)
63.Do all cells have a nucleus? (I)
64.How are the vacuoles in various cells alike and different? What is the purpose of vacuoles? (U)
65.Does dandruff contain cells? (I)
66.What does the protoplasm inside your cheek look like? (Scrape your cheek with a toothpick and place the material in a drop of water on a glass slide.) (I)
67.How do the size of cells vary in various plants and animals? (I)
68.How big are the largest cells? (Try the yolks of various birds’ eggs.) (P)
69.To what lengths can cells grow? (Try various nerve cells.) (U)
70.How big are the smallest cells? (U)
71.Are bacteria living things? Are they plants or animals? (I)
72.Are viruses living things? (U)
73.What is the difference between cells and tissues? (I)
74.How do different kinds of tissues in various animals compare (covering tissue, muscle tissue, and connective and supporting tissue, such as blood, nerve, fat, bone, and fibrous connective tissue)? (U)
75.What is the difference between tissues and organs? (I)
76.How do the tissues from various heart organs compare? (U)
77.Do plants have organs? Can you compare the organs of various plants? (U)
78.Is protoplasm a mixture or a compound? (U)
79.What percent of various plants and animals is water? (Try different fruits and vegetables as well as various insects.) (I)
80.What materials make up protoplasm? Can you make up artificial protoplasm? (U)
81.Are plants as sensitive to stimuli as animals? (P)
82.How do various living things grow? (P)
83.How does a bone grow? (U)
84.Grow a mimosa plant. Try various experiments with this unusual plant. (I)
85.What are the conditions necessary for the life of a brine shrimp? (I)
86.How are living things classified? (I)
87.Collect various plants. Can you divide the plants up into their correct phyla? (Remember the four basic parts: roots, stems, leaves, and flowers.) (U)
88.How are animals classified? Can you classify various animals? (I)
89.Collect various forms of thallophytes (plants without roots, stems, leaves, or flowers). Can you divide these into their correct subphyla: algae or fungi? (U)
90.Are algae found in both fresh and salt water? (I)
91.How many different kinds of algae can you locate? What is the difference in the cells of these algae? (P)
92.What is the appearance of algae? Scrape some algae off the side of a tree (pleurococcus) and compare under the microscope with pond scum algae (spirogyra). (P)
93.Can you divide various algae into their color classes: green, blue-green, brown, and red? (U)
94.Will fish eat algae? (P)
95.Can algae be used as fertilizer? (I)
96.Can you extract iodine from kelp algae? (U)
97.Can you use algae as a food material? (I)
98.What is the rate of growth of different algaes? (P)
99.Will algae grow without sunlight? (P)
100. Under what conditions will algae grow the best? (P)
101. Does algae seek light? (phototropism) (I)
102. How does algae reproduce? (U)
103. Is some saltwater algae adaptable to fresh water? (U)
104. What animals will eat food made of algae? (U)
105. Is algae nourishing? (I)
106. Can you collect different kinds of fungi and divide them into parasites and saprophytes? (U)
107. Which fungi are helpful and which are harmful? (U)
108. How small are various forms of bacteria? Can you measure bacteria? (I)
109. Can you find bacteria in the air? (P)
110. Can you find bacteria in water? (I)
111. Can you find bacteria in soil? What conditions produce the most bacteria? (P)
112. Which bacteria live on dead material? (U)
113. Which bacteria live on living material? (U)
114. What do bacteria look like? Can you divide bacteria into their groups (rod-shaped, spherical, curved, or spiral)? (U)
115. Where do bacteria grow? (P)
116. What kinds of bacteria do you find around your home? (P)
117. What kinds of bacteria do you find in your school? (I)
118. What kinds of bacteria do you find on your body? (U)
119. How fast do bacteria grow under certain conditions? (P)
120. Will bacteria grow in darkness? (P)
121. Will bacteria grow in freezing temperatures? (P)
122. What effect does humidity have on the growth of different kinds of bacteria? (I)
123. Can you experiment with beneficial uses of bacteria? (U)
124. Can you experiment with harmful uses of bacteria? (U)
125. How does bacteria help the food industry? Be sure to experiment with these processes. (U)
126. Can you repeat the work and discoveries of Anton van Leeuwenhoek and his work with bacteria? (U)
127. Can you repeat the work of Louis Pasteur and his experiments with bacteria? (U)
128. What does yeast look like under the microscope? How large are yeast cells? (P)
129. What bacteria cause disease in animals? (U)
130. Are all yeast cells alike? (I)
131. What effect do yeast plants have on sugar? Can you identify the products given off? (U)
132. Under what conditions does yeast grow the best? Vary the temperature, solution, light, etc. (I)
133. Are all molds alike? (P)
134. How do molds reproduce? What conditions are favorable for mold reproduction? (I)
135. How large do molds grow? (P)
136. Is light necessary for the growth of molds? (I)
137. Are the tubes of mold plants attracted by the pull of gravity? (I)
138. Can you produce mutations with bacteria, yeast, and molds? Try exposing them to ultraviolet, and other forms of light rays and radiation. (U)
139. What mushrooms are edible? Which are poisonous?36 (U)
140. Will mushrooms grow in the dark? In the light? (I)
141. What temperature extremes can mushrooms stand? (I)
142. How do mushrooms reproduce? What conditions are the most favorable? (U)
143. Under what conditions will lichens exist? (P)
144. Will lichens grow without moisture? Sunlight? (I)
145. On what material will lichens grow? (P)
146. Will lichens continue to grow under freezing conditions? (U)
147. What do the cells of lichens look like under the microscope? (I)
148. What is the effect of radiation on lichens? (U)
149. What is the altitude range for various forms of lichens? (U)
150. What environments are favorable for the growth of mosses? (I)
151. Why do mosses grow so low to the ground? (P)
152. Where are liverworts found? What conditions are favorable for their growth? (I)
153. Will liverworts live in water? (I)
154. What are the beneficial uses of liverworts? (I)
155. Can you experiment with the environment of various ferns found in the area? (U)
156. Why do ferns grow higher than mosses? (P)
157. Can ferns adapt to a saltwater environment? (I)
158. Under what conditions will the horsetail fern continue to survive? (I)
159. Can you produce mutations in various seed plants? (U)
160. How are the seeds of various plants transferred for reproduction? (P)
161. How much water is really needed by the various seed-growing plants? (P)
162. What kind of conifers are in the region around you? What percentage of each do you find? (I)
163. How do the seeds of various conifers compare? What is their weight and area? Under what conditions will the seeds start growing? (I)
164. Can you experiment with different kinds of seeds and then test whether they will grow? (P)
165. Can you experiment with the reproductive parts of various flowering plants? (U)
166. Can you divide seeds from many different plants into their classes: monocots (one-piece) and dicots (two-piece)? (U)
167. Are Euglena animals or plants? (U)
168. Do the Euglena need light in order to live? (I)
169. How do different protozoa (amoeba, paramecium, vorticella, etc.) react to changing environment, such as heat, light, electrical field, magnetic field, various gases, and other protozoa? (U)
170. What do various forms of protozoa eat? (I)
171. Where are various forms of protozoa found naturally? (I)
172. What are the problems of culturing various forms of protozoa? (I)
173. Can you cause mutations among the different protozoa? (U)
174. How do the different protozoa reproduce? Study only one at a time. (U)
175. Can protozoa think? Experiment with different stimuli. (U)
176. Can sponges adjust to water containing less salt than ocean water? (U)
177. How much water can various types of sponges hold? What determines this capacity? (U)
178. Can you start sponges growing in a different environment? (U)
179. How do sponges reproduce? (U)
180. What do coral eat? Can coral adjust to changing temperature of water? (U)
181. How are coral islands formed? Can you determine the rate of growth of such a coral deposit? (U)
182. Where can hydra be found around your area? (I)
183. What will hydra eat? How do hydra feed? (I)
184. Are hydra affected by electrical stimuli? (U)
185. How do hydra reproduce? (I)
186. How do jellyfish compare with hydra? (I)
187. How long does it take the nerve cells of a jellyfish to react? (U)
188. What will jellyfish eat? How do jellyfish locate their food? (U)
189. What is the power of the stinging cells of the jellyfish? (U)
190. Are jellyfish adaptable to changing environment? (U)
191. Will jellyfish regenerate parts? (I)
192. What parasitic worms live in or on different animals? (U)
193. Can parasitic flatworms regenerate parts? (I)
194. Can Planaria regenerate parts? Try different experiments with Planaria. (I)
195. What hostile conditions can Planaria survive? (I)
196. Can you experiment with the life cycle of the tapeworm? (U)
197. Can tapeworms regenerate parts? (U)
198. What temperature is necessary to destroy various types of roundworms and flatworms? (I)
199. Does apple cider contain roundworms? Are these worms harmful? (I)
200. Can you conduct various experiments with vinegar eel worms? (U)
201. What effect do earthworms have on the soil? (P)
202. Do earthworms prefer an acid or alkaline soil? (I)
203. How do earthworms breathe? (P)
204. How do earthworms reproduce? Can you raise worms? (P)
205. How does light stimuli affect earthworms? (P)
206. What temperature variations can earthworms stand? (I)
207. What parts of an earthworm can regenerate? (P)
208. Are earthworms attracted by electricity? (I)
209. How do earthworms react in a magnetic field? (U)
210. Can earthworms learn? (I)
211. What is the metabolism rate of the earthworm? (U)
212. Are earthworms ever frightened? (U)
213. How far under the surface of the ground can earthworms live? (U)
214. Can you experiment with the internal structure of the earthworm? (U)
215. Are fish attracted to the color or odor of the earthworm? (I)
216. What kind of diet is best for earthworms? (I)
217. Can you cause mutations in earthworms? (U)
218. How strong is the grip of a starfish? (I)
219. What will starfish eat? (I)
220. How far will a starfish move in a day? (I)
221. Will all starfish atomize (throw off an arm)? (P)
222. Will one arm of a starfish regenerate a whole body? Experiment with various forms and conditions of regeneration among starfish. (I)
223. Can starfish tolerate some fresh water? (I)
224. Can starfish stand great temperature variations? (I)
225. Do starfish exhibit a positive or negative trophism toward light? Is this true for all wave lengths of light? Try colored light. (I)
226. How strong is the resistance of the bivalve mollusk against having its shell opened? (I)
227. How fast can a mollusk move? (Pick a certain member, such as a clam.) (I)
228. Can you grow a pearl in an oyster? (U)
229. How does a sea snail keep water in his shell and air out of his shell when he is exposed to the air between tides? (I)
230. How watertight is the operculum of different members of the ocean snail family? What materials and liquids can these snails resist and for what periods of time? (U)
231. How fast can different members of the land snail family move? (P)
232. How fast is a slug? Compare the land slug with the sea slug. (I)
233. Can members of the octopus family regenerate parts of their body? (U)
234. What is the composition of the poison of the octopus? (U)
235. Can lobsters see? (P)
236. Can a lobster or crayfish swim? How do they move? (P)
Spiders and Insects
237. How do different spiders spin their webs? (P)
238. How strong are the webs of different spiders? (I)
239. Do all spiders bite? How? (P)
240. What do spiders eat? (P)
241. Do all spiders spin webs? (P)
242. Will one spider get caught in the web of another kind of spider? (P)
243. How does a spider avoid being caught in his own web? (I)
244. How fast can the different members of the spider family move? (I)
245. Can spiders see? How well can they see? (I)
246. Can spiders detect odors? (U)
247. What environmental changes can the spider withstand? (I)
248. What environmental changes (gases, temperature, etc.) can the different mites withstand? (U)
249. Does each spider have but one web? Do more than one spider share the same web? (I)
250. How many legs do centipedes have? How about millipedes? Do they vary? (I)
251. What do centipedes eat? (I)
252. Do millipedes exhibit a positive or negative tropism toward light? (I)
253. What do millipedes eat? (I)
254. What kind of insects live in your area? Pick out one small area and keep a record throughout the year. (P)
255. What insects are helpful to man? How? Can you find examples? (P)
256. What insects are harmful to man? How? Can you find examples? (P)
257. What are the characteristics of an insect? (Examine a grasshopper.) (I)
258. How do insects smell and feel? (P)
259. Can you investigate the vision of various insects? (I)
260. Can you measure the number of vibrations per second that various insects move their wings? (I)
261. How do insects hear? Can you compare the hearing ability in various insects? (U)
262. How do various insects breathe? Can you figure the metabolism rate? (U)
263. How do various insects reproduce? How do you tell the males from the females? (U)
264. Can you experiment with some of the body processes of insects? (I)
265. Can you experiment with the eggs of various insects to determine hatching conditions? (U)
266. Can you determine the amount of plant material a caterpillar or other insect will eat in the larval stage? (I)
267. Can you collect various insects and divide them into their correct order according to their wings or other determining factors? (I)
268. Can you collect and study several types of moths and butterflies in order to determine the difference between the two? (I)
269. Can you breed houseflies and determine their life cycle? (I)
270. Can you experiment with the environment of the housefly, with an idea of exterminating the fly? (U)
271. Can you experiment with the raising of mosquitoes? (U)
272. Can you experiment with the environment of various types of mosquitoes? (U)
273. Can you experiment with different types of odors and their effects on mosquitoes? (U)
274. How does man control the mosquito? (I)
275. Can you measure the strength of various insects? (I)
276. Can you measure the flying speed of various insects? (U)
277. What insects will destroy others? Can you experiment to determine this? (I)
278. How strong are the wings of various insects? (U)
279. Can you experiment with the diet of various insects? (I)
280. Can you determine the weight of various types of insects? Can you take other physical measurements? (U)
281. Can you compare the wings of various insects as to construction, size, etc.? (P)
282. What insects are attracted to light? What insects have a negative tropism? (P)
283. How much light is given off by a firefly? (U)
284. What insects do damage in your locality? (P)
285. Can you compare the pollination of certain plants by insects as compared to similar plants that have been screened to prevent insect pollination? (U)
286. How do various insects spend the winter? Where can you find them during the winter? (P)
287. Why are insects so successful? (U)
288. Can insects think? How intelligent are the various forms? (U)
289. What insects must be exposed to a constant source of moisture in order to avoid drying up? Can you test various insects, including some found in the soil? (I)
290. What is the effect of changing temperature on the rate and duration of light from the firefly? (U)
291. What are the mineral requirements of the fruit fly, Drosophila? (U)
292. What do fruit flies eat? (P)
293. What is the effect of high and low temperatures on the housefly? (I)
294. What is the effect of different sound waves on bees, particularly drones? (U)
295. Can insects such as grasshoppers communicate? Try separating the males and females and use the mating sounds to test your idea. (U)
296. How do different insects react to the stimuli of loud sounds? (P)
297. Can water beetles hear under water? What frequencies are the easiest to hear? (U)
298. When you try to catch a fly, is it the shadows or the air current which give the fly a warning? (I)
299. Can flies learn or become conditioned? Try conditioning them to escape from some trap. (I)
300. What insects exert a positive tropism or attraction toward a breeze or small wind? Which insects will face into the wind? (I)
301. Will the human breath activate insects? Try ants, stick insects, or butterflies on cold mornings or in cool temperatures. (I)
302. What is the effect of nicotine on various insects? Can certain insects stand cigarette smoke? (U)
303. How long can certain insects live on the following diets: sugar water; raw meat? Be sure to try blowflies as well as other insects. (I)
304. Does an insect’s diet affect reproduction? (U)
305. How long does it take mosquitoes to digest blood? Remember, you can see the red coloration of the blood through the swollen abdomen. (I)
306. What is the effect of vision on an insect’s movement? Blindfold the insect by painting the eyes black. (I)
307. Can you hypnotize stick insects? Try rolling them between your fingers. (I)
308. What other animals can become immobilized? (chicken, crayfish?) (U)
309. Why do some people react more violently to mosquito bites than others? (U)
310. How does the length of the trachea affect the size of an insect? (I)
311. What effect does temperature have on the frequency and amplitude of the respiratory movement of insects? Use stick insects, bees, moths, or beetles. The insect can be magnified by being placed in the beam of a projector. Watch the shadow. (I)
312. What is the effect of added carbon dioxide in the air on the respiratory rate of insects? (I)
313. What conditions are necessary for a rich oxygen supply in water? (P)
314. What is the effect of stagnant or warm water on the amount of oxygen dissolved in the water? (I)
315. What effect does water with little dissolved oxygen have on the respiration of such water insects as water beetles and water insect larvae? (U)
316. What periods of the day are certain insects the most active? (P)
317. Will the pattern of activity set by insects be upset by periods of continuous darkness and periods of continuous illumination? (I)
318. What is the walking order of the legs of various types of insects? How does the insect modify his walking pattern with the removal of one or more legs? (I)
319. What insects will atomize their legs easily (shed one or more legs)? (P)
320. How long does it take various forms of insects to make the necessary adjustments in coordination after the removal of one or more legs? (U)
321. Can you calculate the wingbeat of various insects? What is the effect of added load to the wings (wax added) on the number of vibrations? (U)
322. What is the effect of temperature on the time it takes a moth to flutter before it can fly? (Keep one hot and one cold.) (I)
323. How long can a fly stay submerged in water or alcohol and still live? Submerge an insect in a mixture of alcohol and paraffin and then observe under a lens. (I)
324. Why don’t insects dry up from evaporation of the water in their bodies? Remove the wax from the cuticle of the insect by dusting the cuticle with charcoal powder. (U)
325. What insects may be charged by static electricity? (I)
326. What insects can change their body color? How is this change possible? (U)
327. How do caterpillars react to a physical stimulus such as a slight touch? Experiment on various parts of the insect. Are all reactions alike? (I)
328. What are the reactions of the caterpillar to stimuli such as heat and cold? (P)
329. How do various insects, such as caterpillars, react to vibrations? (P)
330. Do water beetles react to red light? (I)
331. How do water beetles avoid contact in a pond or aquarium? (U)
332. What effect has contact of the tarsi of an insect with a solid object have to do with the flight of the insect? (U)
333. How do different insects regain their normal posture when turned over? Can you inhibit this? (U)
334. Do stick insects exhibit a falling reflex? How does this compare with a cat? (I)
335. What effect does vision have on the movement of the dragonfly? Paint the eyes. (U)
336. Can bees be trained to go to a water container? (U)
337. How does the smelling ability of various insects differ? Have a test tube containing food and another without food. Make an insect maze. (I)
338. How does the touching of the tarsi of the front legs of various insects (bees, flies, etc.) with a sugar solution affect the movement of the mouth parts? (U)
339. Can bees distinguish between saccharin and sugar? Can you experiment by adding different substances to syrup and then testing the bees’ preference? (U)
340. Can bees discriminate or detect higher and lower concentrations of sugar? (U)
341. Can bees learn? Use the results from the previous question. Use dishes of different concentrations of sugar. Later test the memory of the bee. (I)
342. How do ants follow the trail of other ants? Try making an artificial trail with a weak solution of formic acid. (I)
343. How does a bee communicate to other members of a hive the direction and location of a rich source of honey? (U)
344. Which insects have a negative tropism toward the pull of gravity? Try water bugs and other insects. Use a seesaw that tilts under the weight of the insect. (I)
345. Why does an insect crawl up to the end of a branch or leaf and then reverse direction and go downward? Try flies, ants, etc. in a sealed bottle. Can you change the direction the insect wants to go by turning the bottle end for end? (P)
346. Is the pig louse attracted by temperature and/or smell? What is the effect of different kinds of surfaces upon its movement? (U)
347. What is the preferred temperature of various insects, such as flies, beetles, fruit flies, etc.? (I)
348. Can you experiment with the effect of vision on an insect’s ability to move? Paint the right eye on some, the left on others, and both on some. (U)
349. Can you experiment with the effect of different colored light and the absence of light on the flight of the moth and other insects? (P)
350. What larvae, pupae, and marine life react to the stimuli of a moving shadow? Is the reaction due to the movement or the change in light intensity? (U)
351. When you chase flies, why do they head for the window? Is the reaction due to the light? (I)
352. Do social insects such as ants, bees, and termites use the position of the sun in order to help find their directions? (U)
353. Will certain insects, such as beetles, caterpillars, and stick insects change their direction of movement when the direction of light (use a flashlight bulb) is changed? Try using two different light sources that can be turned on and off. (U)
354. Can you investigate the mating instincts of the housefly? (U)
355. What are the problems involved in training bees? Can you devise a bee IQ test? (U)
356. What forms or designs can bees distinguish? (U)
357. Can bees tell time? Feed bees a sugar solution at a certain time each day. Will bees show up only at this time after a few days of conditioning? (I)
358. What changes occur in insects (such as stick insects) after molting? Be sure to check all body parts and weigh the insect. (U)
359. What insects have the power of breaking off their body parts? Which ones can regenerate these parts? Try stick insects and grasshoppers. (I)
360. Does regeneration of legs occur just in the young insects, or can adults do it too? (I)
361. Do bees visit more than one type of flower, or does each individual bee stick to one particular type? (U)
362. Upon what conditions does the number and size of larvae in a given culture medium depend? (I)
363. What is the difference between a butterfly and a moth? Can you observe both through a life cycle? (P)
364. What insects are bugs? What is the difference between bugs and other insects? (P)
365. How do the wings of various insects differ? (P)
Fish, Reptiles, and Amphibians
366. Are fish cold- or warm-blooded? Can you measure the temperature of a fish? (I)
367. How do scales help fish? How do the scales of various fish compare? (I)
368. How do different fish move their fins? What determines the rate of movement of fins? (U)
369. How do the gills in a fish remove oxygen from the water? (I)
370. What fish can adapt to changing amounts of salt in the water? (I)
371. What is the difference between toads and frogs? Can you discover this by observation? (P)
372. Can you keep a record of the changes in the life cycle of a frog from the egg to the adult stage? (P)
373. What effect does temperature have on the hatching of frog eggs? (I)
374. What animals will eat frog eggs? (U)
375. What effect does temperature have on the mating instinct of frogs? (U)
376. Do people get warts from touching toads? (P)
377. What is the difference between salamanders, newts, and lizards? Can you discover this by observation? (P)
378. How far can frogs jump? (P)
379. What effect does temperature have on the rate of movement of different kinds of amphibians? (I)
380. How and what does an amphibian eat? (P)
381. What effect does temperature have on the rate of motion of various lizards? Try snakes, turtles, horned toads, etc. (P)
382. What changes in environment can turtles withstand? Can turtles be frozen in a block of ice and still live? (I)
383. Can you analyze the poison from different reptiles? (U)
384. How are poisonous animals useful? (U)
385. Will turtles eat frogs? (I)
386. How strong are turtles? What is one turtle power? (P)
387. How strong is the turtle’s jaw? (I)
388. What effect has the direction of light on a turtle’s motion? (I)
389. How does a chameleon change color? (I)
390. What happens to reptiles and amphibians in the winter? Can you use a refrigerator to duplicate these conditions? (I)
391. What is the difference between crocodiles and alligators? (P)
392. What kinds of snakes are found in your locality? What can you observe about them? (P)
393. Are snakes intelligent? Can snakes remember? (I)
394. What percentage of the population is afraid of snakes? How does this change with age? (P)
395. Why do many people dislike snakes? Is this based on personal experience? (P)
396. What are the food habits of various snakes? (I)
397. What squeezing force can be exerted by different members of the constricting family? (U)
398. What snakes are nocturnal? Can some snakes see in the dark? (I)
399. How does a snake smell? (I)
400. Can snakes see? Do they depend on vision or smell in searching for food? (U)
401. How do snakes react to different stimuli, such as sound, different colored lights, etc.? (P)
402. How do snakes get moisture? Can snakes live without water? (P)
403. How does a snake move? Do all snakes move in the same way? (P)
404. Can lizards regenerate parts? How long does regeneration take? (I)
405. What effect does age have on a lizard’s ability to regenerate? (U)
Birds and Mammals
406. What birds do you observe around your locality? Do you see different types of birds at different times of the year? (P)
407. Do birds have backbones? How do the bones of a bird compare with those of a mammal? (I)
408. Are birds cold-blooded? What is the temperature of the body of different kinds of birds? Does this temperature vary? (P)
409. What can you tell about a bird from its feet? (I)
410. What do the different varieties of birds eat? How much will they eat? (I)
411. Does the food consumption of birds depend upon the temperature of the air? (U)
412. How do hawks and owls locate their food? (U)
413. Can hawks and owls see in the dark? (U)
414. What birds eat seeds of weed plants? (U)
415. Are scavenger birds helpful? How do they locate their food? (U)
416. What is the body temperature of different kinds of mammals? Does this temperature vary? (P)
417. How does the milk of different kinds of mammals compare? Which is the healthiest? (U)
418. Do all mammals have four-chamber hearts? Compare heart size with body weight. (U)
419. What temperature do the various types of mammals prefer? Try white rats, guinea pigs, kittens, etc. (I)
420. What can you tell about an animal from its teeth? How do the teeth of various mammals compare? (I)
421. Compare the intelligence of various types of mammals with your own IQ test. (U)
422. How do various mammals make sounds? How are these sounds helpful? (I)
423. Can you compare the blood of various mammals, reptiles, amphibians, and birds? How do the cells compare? (U)
424. What animals are easy to condition? (I)
425. What is the temperature range of various mammals? (I)
426. How do nests of various birds compare? Which is the strongest? (P)
427. What is the safety factor of bird nests? How much weight can various nests hold as compared with the number and weight of the eggs of different birds? (P)
428. How do birds and mammals prepare for the winter? Can you observe some? (P)
429. Can birds smell? How do birds hear? (U)
430. Can birds and mammals recognize their own young? Does odor or appearance help? (I)
431. Do birds live in one particular area, or do they travel great distances in a day? (U)
432. Can birds be trained by artificial calls? (U)
433. Can you compare the strength of various animals? How does this strength compare with the size of the animal? (I)
434. Can you measure the metabolism rate of various mammals and other forms of life? (U)
435. What causes fear in different animals? Can you measure fear by using the metabolism rate? (U)
436. Are white rats instinctively afraid of snakes, or is this learned behavior? (U)
437. What effect do various stimuli have on the metabolism rate of certain birds and mammals? (U)
438. What effect do different diets have on the growth rate of mammals? (U)
439. How does the temperature affect the hatching rate of various fowl? (U)
440. Can chickens be hypnotized? (U)
441. What effect do different kinds of music have upon the egg production of chickens? (U)
Plants and How They Grow
442. How do leaves vary in size, shape, and structure? (P)
443. Which seeds are monocots (single seed leaf), and which seeds are dicots (seeds with two halves)? Try corn, beans, peas, rice, and oats. (P)
444. How do the leaves of monocots and dicots differ? Examine corn and beans as two examples. (P)
445. Where do the colors of the leaves in autumn come from? (P)
446. How does a tree lose a leaf? (U)
447. Do evergreen trees ever shed their leaves or needles during a year? Mark certain needles and examine during the year. (I)
448. What are the internal parts of a leaf? (U)
449. Is the green substance in leaves (chlorophyll) distributed evenly throughout the leaf cell? Cut a cross-section of a leaf (elodea) and examine under the microscope. Try other plants. (U)
450. What plants secrete a waxy substance (cuticle) that covers the outside of the leaves? What is the purpose of this waxy covering? (P)
451. What purpose is served by the veins in leaves? (P)
452. Will a plant live in pure oxygen? (I)
453. Will a plant live and grow in pure carbon dioxide? Make some carbon dioxide and find out. (I)
454. What percentage of carbon dioxide can plants tolerate? (I)
455. Is the epidermis or outside covering of a leaf transparent? If so, why? (I)
456. What is the function of the guard cells and the stomates in leaves? On which side of the leaf are most of these found? Why? (U)
457. What are the sizes of stomates in various plants, such as corn, apple tree leaf, and lily? Can you measure these and determine the number per square inch? (U)
458. What product or gas is given off as a result of photosynthesis? Can you collect the gas by covering a water plant with a funnel and collecting the gas with a test tube? Be sure the water contains carbon dioxide. (P)
459. What effect does light have on the rate of photosynthesis? You can use the same equipment as you used in the previous problem. (P)
460. Do plants require light to manufacture food? Place one plant in the dark and another plant in sunlight. Check the leaves for sugar. Grind up the leaves to get the sap out of them. Add Benedict’s solution to each. The solution should turn brick red if glucose (sugar) is in the sap. (U)
461. Will a plant carry on photosynthesis if the stomates are covered in the bottom part of the leaf? Cover the bottom part of the leaf with Scotch tape or a thin wax. (I)
462. What kind of gas is given off by animals as a waste product of breathing? (I)
463. Can you measure the amount or rate of carbon dioxide production by different animals? (U)
464. Can plants use the carbon dioxide given off by animals? Place plants and animals in a box. Note how long the plant remains healthy. Try the experiment again, but this time without the animal. (I)
465. Can animals use the gas given off by plants? Try the experiment given before, but this time remove the plant. (I)
466. Is the rate of photosynthesis influenced by the temperature? (I)
467. Is the rate of photosynthesis influenced by the intensity of the sunlight? (U)
468. Is the rate of photosynthesis influenced by the amount of carbon dioxide in the air? (U)
469. Is the rate of photosynthesis influenced by the amount of water present? (I)
470. At what temperature extremes can algae carry on the processes of photosynthesis? (U)
471. What are the light requirements of various plants? (I)
472. How do plants adapt themselves in order to receive the exact amount of light necessary for growing? (P)
473. What color rays in sunlight are used in the process of photosynthesis? Experiment on plants by using colored lights or a colored filter with sunlight. (I)
474. What color ray from sunlight is not absorbed at all by the leaf? Remember the color of the leaf. (I)
475. How much water is used by different plants? Can you think of a way to measure the water consumption? (I)
476. Do plants manufacture proteins? How can you prove this? Do you know a test for proteins? (U)
477. How strongly do the root systems of various plants anchor the plants to the soil? Can you measure the pull required to remove the plant? (I)
478. What effect do different kinds of soil have on the ability of roots to anchor plants in the ground? (I)
479. How do the roots of various plants compare? (P)
480. How does the amount of moisture available affect the length of the root system in various plants? (U)
481. Do all roots grow in the soil? How about air and water roots? (U)
482. How does the size of the root system affect the amount of water evaporated from the leaves of various plants (transpiration)? (U)
483. What is the structure or make-up of roots and root hairs? Examine the roots of young bean or wheat plants. You may start the plants by placing the seeds on damp blotting paper in a dish and then covering the dish. (P)
484. How does soil water enter a root? What is osmosis? Use a carrot for your root. Make a carrot osmometer and experiment with sugar solutions. (I)
485. Why does grass die when a strong solution of salt water is poured on it? (U)
486. Can you experiment and determine the osmotic pressure of various solutions through different membranes? (U) .
487. Can you analyze the soil around you as to composition and percentage of composition? Can you make an artificial soil with chemicals? (U)
488. How are soils kept fertile? Can you experiment with the fertility of different soils? (I)
489. How is nitrogen supplied to the soil naturally? Can you experiment with the bacteria found in legume plants (clover, peas, beans, and alfalfa)? (U)
490. Can you extract nitrogen from the air and make your own fertilizer? (U)
491. Can you experiment by making your own fertilizer and using it on plants? (I)
492. Will fish serve as a good fertilizer? Plant some beans or corn over a buried fish. (P)
493. What foods, animals, or plants make good fertilizer? (I)
494. Can you experiment with crop rotation? (I)
495. Can you grow plants in water (hydroponics)? (P)
496. Can you experiment with different kinds of chemicals in the growing of plants in water? (I)
497. What effect has temperature on the growth rate of plants grown in water? (U)
498. What plants can be grown successfully by the hydroponic method? (U)
499. What is the effect of different amounts of sunlight on plants grown by the hydroponic method? (I)
500. How do stems serve plants? Can you compare the stems of different plants? (I)
501. How do the roots of plants get food material? Where does the food come from? (I)
502. Can stems carry on the process of photosynthesis? (U)
503. How does a cactus plant carry on the process of photosynthesis? (U)
504. Can the cactus plant adapt to a changed environment? (I)
505. How does a cactus plant retain its moisture? (I)
506. How do the stems of dicots and monocots differ? Use a cross-section of a corn stem and a cross-section of a sunflower stem. (U)
507. What plants (dicots) in your region are killed to the ground by frost in the fall? What plants survive frost and are able to grow again in the spring? (P)
508. What plants (herbaceous) in your region live only one year? What plants live two years? What plants live more than two years? What determines the length of life of a plant? (I)
509. How does a tree or shrub grow? Can you observe and record the results over a period of time? (I)
510. Can you take cross-sections of stems of a plant to show the growth and change in the cells? (U)
511. What time of the year do plants (trees, shrubs, flowering plants) show the most growth? Can you measure the growth at different times of the year? (P)
512. How does a tree grow? Does the area of the xylem (water-conducting tubes) increase faster or slower than the area of the phloem (food-conducting tubes)? (U)
513. Why do the cells of the xylem vary in size? Can you compare xylem cells in different plants and trees? (U)
514. Can you determine the age of trees around you from examining the growth rings on stumps? Can you determine what years the tree grew the most and what years it grew the least? How does this compare with the weather cycles? (P)
515. Can you determine the year in which various trees started to grow by comparing growth rings on stumps with the growth rings of a tree whose age is known? (I)
516. Will a tree die if the bark is removed in a ring all around the tree? Try different places on a tree. Try this experiment on branches. (P)
517. What use is the bark to a tree? How much bark is necessary for the tree to keep alive? (I)
518. What effect has the removal of some bark of a tree on the growth rate of the tree? Can you find examples in nature of bark removed from a tree? (U)
519. How do twigs of different kinds of trees differ? (P)
520. Can you determine the growth rate of growing trees by measuring the distance between the bud scale scars? How does the growth rate compare with the climate? (U)
521. Do all trees grow at the same rate? Use the method above to determine this. (I)
522. How does water move upward in plants and trees? Is this movement of water due to osmotic pressure of water moving into the roots and forcing the water up? Is it due to capillary action of water being lifted up by the hairlike tubes in the plant? Is it due to the evaporation of the water off the leaves? (U)
523. How does temperature affect the rate the water rises through the capillary tubes of a plant? Use a stalk of celery and colored water. (P)
524. Will plants lift up liquids other than water? How does the rate compare with that of water? (I)
525. How much water is given off by leaves of various plants and trees (transpiration)? (P)
526. How does the rate of transpiration vary with the season? (I)
527. How does the rate of transpiration vary with the humidity of the air? With the temperature? (U)
528. How do various insectivorous plants (Venus flytrap, sundew, and pitcher plant) attract insects? (P)
529. What effect has temperature on the sensitivity of the Venus flytrap? (I)
530. How do insectivorous plants digest and use their food? (U)
531. Do insectivorous plants need sunlight? (P)
532. What kind of insects will various insectivorous plants eat? (I)
533. Can you compare the growth rate of insectivorous plants with the amount of food supply? (U)
534. What effects have various fertilizers on the growth of insectivorous plants? (I)
535. Can you analyze the digestive juices of insectivorous plants? (U)
536. How do various insectivorous plants capture insects? (P)
How Plants and Animals Use Food
537. What foods contain starches? Test by using a few drops of dilute iodine. A resulting color of blue-black indicates starch.37 (P)
538. What foods contain sugars? Test by putting a sample of the food material in a test tube with an equal amount of water. Add a few drops of Benedict’s or Fehling’s solution. The color indicating sugar may be red, orange, or yellow depending on the concentration of sugar. (P)
539. Can you determine the concentration of sugar in various foods? (I)
540. Can you measure the amount of energy produced by various foods? Use a calorimeter, an instrument that consists of a chamber for burning food and a jacket for water surrounding the chamber. Be sure to measure accurately the amount of food and the amount of water used in the test. (U)
541. What type of food (fats, carbohydrates, proteins) contains the largest number of calories? (I)
542. How much heat is a calorie? Does it take the same amount of heat to raise all liquids one degree Celsius? (I)
543. What are fats composed of? Can you analyze various fats for their composition? (U)
544. How much energy do fats produce per gram of weight? (U)
545. What foods contain fats? You can test peanuts by chopping them into small pieces and covering them with carbon tetrachloride in order to dissolve the fatty oil. Remove the nuts and allow the carbon tetrachloride and oil mixture to sit. The carbon tetrachloride will evaporate and leave just the oil. Compare the weight of the oil to the weight of the dried peanuts to determine the composition. Try this method on other food.38 (I)
546. Where is fat stored in the body? Examine and dissect some animal. (U)
547. Can you test various foods for protein? Try the white of an egg. Place some in a test tube and add one drop of a 1% solution of copper sulfate and five drops of a 10% solution of potassium hydroxide. The presence of protein is indicated by a purple color. If you are testing solid foods, crush the food and cover with water in the test tube before adding the chemicals. (U)
548. What element is found in proteins and not in fats and carbohydrates? Can you test to find out? (U)
549. What effect does a lack of proteins have on the body? Run an experiment on white rats. (I)
550. Can you identify the various amino acids in proteins by paper chromatography? (U)
551. Which proteins contain the ten essential amino acids? (U)
552. How much energy does one gram of protein produce? Do all proteins give off the same amount of energy? (U)
553. Can you dehydrate various foods and small animals to determine the amount and percentage of water compared to the total weight? (I)
554. How much water is given off by various animals each day? What factors determine this? (I)
555. How much water do different animals drink in a day? How does this amount compare with their body weight? (P)
556. What factors affect the amount of water an animal drinks in a day? (P)
557. Why must the body have water? (I)
558. Why is iron needed in the body? What is the effect of a lack of iron in the body? Can you carry on this experiment on a white rat? (I)
559. What foods are good sources of iron? Can you test this food for the presence of iron? (U)
560. Why is phosphorus needed in the body? Carry out an experiment using a diet which lacks phosphorus. (U)
561. Why is calcium needed in the body? Carry out an experiment to determine the effect of a lack of calcium in the body. (U)
562. What effect does a lack of iodine have on the body? Does your soil contain iodine? Can you test to find out? (U)
563. What effect does a lack of sodium have on the body? Can you experiment using a salt-free diet? (I)
564. Is salt given off by the body when we perspire? (P)
565. What other minerals are needed in the body? (I)
566. How can you detect minerals in foods? Burn bread or sugar by heating them in a jar lid. The ashes left are minerals. Can you determine the proportion of minerals to the total weight of various kinds of foods? (I)
567. What is the effect of a lack of vitamin C in our diet? Can you carry on a controlled experiment with a white rat? (P)
568. What is the effect of a lack of vitamin A in our diet? (I)
569. What foods contain vitamin A? Can you test for vitamin A? What does this vitamin look like? (U)
570. How do fats in the diet help prevent vitamin A from being wasted? (U)
571. What symptoms result from a lack of the vitamin B complex? (U)
572. What do the different vitamins look like under the microscope? How can you locate vitamins? (U)
573. How can you detect vitamin C in food? What foods contain vitamin C? Boil about a fifth of a quart of water. Add a teaspoonful of starch. Use about ten drops of this mixture with one drop of iodine. Add this to one-fifth of a quart of water. Then slowly add lemon or orange juice until the blue color disappears. Try apples, pineapples, and other fruits. (U)
574. Are vitamin D deficiencies found more among dark- or light-skinned people? Does sunlight contain vitamin D? (U)
575. What effect has vitamin E on the ability of rats to reproduce? Is this true of other animals? (I)
576. How is vitamin K produced? What help is vitamin K? (U)
577. What effect has temperature on vitamin loss? (I)
578. What vitamins are destroyed by water? (I)
579. Can you determine the basal metabolism (chemical changes going on while the body is at rest) of yourself? Of other animals? Measure the amount of oxygen used and the amount of carbon dioxide given off since chemical action in your body uses up oxygen in its production of energy. (I)
580. How many calories of energy are required to perform various activities? Remember, again figure the amount of oxygen used up. (I)
581. How does age affect the calorie requirement of people? (U)
582. How does the size of the individual affect the calorie requirement? (U)
583. What is a balanced diet? (P)
584. What is the most effective way to lose weight, by exercising or eating less food? (U)
585. Is milk a perfect food? (I)
586. Is fish brain food? Can you get smarter by eating lots of fish? (I)
587. Are tea or coffee harmful to children? (I)
588. How true are advertisements about certain foods on the market? (I)
589. What foods lose their vitamins by canning? (I)
590. Is soda pop harmful to the human body? (I)
591. Is fluorine in drinking water harmful to white rats? (I)
592. Can humans detect fluorine in drinking water? (I)
593. Are you taller in the morning or at night? (P)
594. What effect has good posture on health? (I)
595. Can you keep track of your growth rate during the year? Do you grow more in the winter or the summer? (P)
596. Does the season of the year affect your intelligence? Are you smarter in the winter? (I)
597. Is alcohol harmful to the body? Experiment on rats with an alcoholic diet. (U)
598. What is digestion? What happens to food during digestion? (I)
599. What effect does saliva have on starchy foods? Make a starch solution test for sugar. Add equal amounts of saliva to starch solution. Wait for ten minutes and then test again for sugar. (I)
600. What effect does temperature have on the rate of digestion of starch to sugar by saliva? Carry on the experiment as above, but this time hold one test tube in your hand while leaving a control in a stand. (I)
601. Can you analyze your saliva for the chemical composition? (U)
602. Can you compare human saliva with saliva from other animals? (U)
603. Is the food within seeds stored as a starch? Use the iodine test. (P)
604. Do seeds digest starch? Crush bean seeds and then test for starch and sugar. Place other bean seeds on a wet blotter until they germinate. Test again for starch and sugar. What happens to the starch food in the seed? (I)
605. What effect has temperature on the rate of digestion of starch into sugar by seeds? (I)
606. What effect has light on the rate of digestion of starch into sugar by seeds? (I)
607. How does mold digest its food? Wet a piece of bread. Sprinkle some dust on it. Place the bread in a jar and screw the lid down. What do you observe? (P)
608. What is the effect of temperature on the digestive action of the bread mold? (P)
609. What is the effect of light on the digestive action of the bread mold? (P)
610. Can you trace the digestion of various food elements, such as protein, through the various stages into the end product of digestion? (U)
611. Are the end products of digestion the same in all plants and animals? (U)
612. What is an enzyme? Can you separate various enzymes found or secreted by plants and animals? Can you test these enzymes on various food materials? (U)
613. How long is the alimentary canal in various animals? What has the length of the alimentary canal to do with the rate of passage of food from mouth to the anus? (U)
614. Why do you chew food? Put a whole piece of bread in a bottle. Add a measured amount of dilute hydrochloric acid. Next break up the bread into smaller pieces. Repeat the experiment. Which took longer? Why? (P)
615. How can enzymes digest solids? Pour Coke on a piece of raw meat. (P)
616. How does reducing a particle’s size affect the total surface area of the material? (I)
617. How do the teeth of various animals compare with those of a human? What can you learn about an animal’s habits from its teeth? (I)
618. Do toothpastes reduce the bacteria content of the mouth? Compare various toothpastes. (I)
619. What effect does fear, excitement, or other stimuli have on the digestive rate of an animal? Try this on rats. (U)
620. Is the saliva in your mouth acid? Test with litmus paper. (P)
621. Does hydrochloric acid help the enzyme pepsin to digest proteins? Coagulate egg white in a piece of glass tubing by heating in boiling water. Break the glass tubing into sections. Use a .4% solution of pepsin on one part. Use a .5% solution on another part. Use both on a third piece. In which tube does the greatest amount of digestion take place? (U)
622. How does bile in the liver help to prepare fats for digestion? Study the process of homogenizing milk. Compare cream and milk fat droplets under the microscope. (U)
623. Is acid formed in the digestion of fat? Add pancreatin to homogenized milk. Test with litmus paper. (U)
624. Can an animal live without a stomach? Use white rats for this experiment. Be sure to try to determine why.39 (U)
625. What is the function of the small intestine? The large intestine? (U)
626. How is the small intestine adapted so that digested food can be absorbed into the blood and lymph stream? Examine some tissue under the microscope. (U)
627. How does the glucose content of the blood affect the sensation known as hunger? Take a sample of blood before and after meals. (U)
628. How do earthworms digest their food? Dissect earthworms to determine how they compare with humans. (I)
629. What foods do earthworms eat? Observations are necessary. (P)
630. How often and how much do earthworms eat? (P)
631. What effect on food material does the saliva have from the mouth of the grasshopper? This saliva is a dark brown juice. (U)
632. What food will the grasshopper eat? How does the grasshopper chew its food? (P)
633. How often must grasshoppers eat? (P)
634. Can grasshoppers do without water or food for the longer period of time? (P)
635. Do fish chew their food? What use are teeth to a fish? (I)
636. Can you compare the teeth of various fish? (U)
637. Can you compare the digestive systems of fish, frogs, and chickens? (I)
638. Why do birds need bits of gravel or sand in their diet? (P)
639. How can you preserve dissected animals? What is the use of formaldehyde? (I)
640. Will alcohol serve to preserve specimens? (I)
641. What radio or television commercials about digestive problems are correct? Which ones are false advertising? (I)
Cell Structure and Development
642. What part of blood is made up of plasma? What part is made up of cells? Add sodium oxalate to the blood to keep it from clotting. Let the cells settle to the bottom of the test tube or bottle. (I)
643. How large are red blood cells? Can you measure the size under the high power of the microscope? How do human red blood cells compare with those of animals? (U)
644. What is hemoglobin? What effect does it have on the red blood cells? (I)
645. What effect do carbon dioxide and oxygen have on the color of blood? Get some blood from a slaughterhouse.40 Find out how much sodium oxalate is necessary to keep the blood from clotting. Check with a doctor. Bubble air or oxygen through the blood. Then bubble carbon dioxide through the blood. (I)
646. How can you determine the hemoglobin content of blood? Get a blood color scale (hemoglobinometer)41 and compare a drop of your blood with the color on scale. (P)
647. How does the hemoglobin content of a human compare with that of different animals? (I)
648. How can you make a microscope slide of blood and stain it? (U)
649. How does blood of cold-blooded animals compare with that of warmblooded animals? (I)
650. How does the liver select only the worn-out corpuscles to destroy? (U)
651. How long do red corpuscles of various animals live? (U)
652. Can you cure anemia in white rats with vitamin B12? (U)
653. How do you count red corpuscles? (U)
654. What effect does exercise have on the number of red corpuscles in the blood? (U)
655. Can you determine the percentage of white corpuscles as compared to red? Make a blood smear on a slide. Stain with Wright’s stain. After two minutes add an equal amount of distilled water. Pour off the mixture after two minutes and rinse. The red cells will be pink. The white cells will appear blue with purple nuclei. (I)
656. How does the white cell compare with the amoeba? (I)
657. What effect do white blood cells have on bacteria in the body? Can you devise a method of observing this? (U)
658. Do all animals have blood? (P)
659. What is pus composed of? What causes pus? (I)
660. How does an infection affect the number of white corpuscles in the blood stream? Can you take blood counts of the white corpuscles? (U)
661. Does the white corpuscle count go up during a virus infection? (U)
662. How long do white corpuscles live? Where are they produced? (I)
663. What are platelets? What is their function in the blood? Can you devise a way of observing platelets? (U)
664. What percent of plasma is water? Can you collect animal plasma and boil off the water? (U)
665. Is there salt in plasma? After you boil the water off, observe under the microscope. (U)
666. Does calcium aid in the clotting of blood? Add calcium to a sample of blood. (I)
667. What causes blood to clot? How does vitamin K affect blood clotting? (I)
668. How can you determine blood clotting time? Heat a piece of glass tubing. Pull the ends apart so you have a length of fine tubing. Sterilize the tip of your finger with alcohol. Prick with a sterilized needle. Pack the fine glass tubing over the drop of blood. The blood will rush up the tubing. Examine a small bit of tubing each 15 seconds. When you observe fine threads being formed, this is the blood clotting time. (I)
669. How does the blood clotting time of various animals compare with humans? (I)
670. What factors (temperature, humidity, exercise, etc.) affect the blood clotting time? (U)
671. What do you observe when blood clots from a cut? Examine under a microscope or a magnifying glass. (P)
672. Can you keep blood from clotting? Investigate the substance dicoumarol, a substance made from spoiled sweet clove. (U)
673. How is blood typed? Can you type the blood of members of your class?42 (I)
674. What is the most common blood type in your class? Among the boys? The girls? (U)
675. What is a universal donor? A universal receiver? What percentages of each do you find? (U)
676. Do animals have the same types of blood as humans? Can you type animal blood? (U)
677. Can animals (white rats, etc.) receive transfusions? (U)
678. How can you determine the Rh factor in blood? (U)
679. How long can whole blood be stored? What effect does temperature have on the storage of blood? (U)
680. Why is plasma given instead of whole blood? How can plasma be stored? (I)
681. What is dextran? How can it replace plasma for transfusions? (U)
682. What does the heart really sound like when it is pumping blood? Make or borrow a stethoscope and listen to heart beats of various people. (P)
683. What is the average heartbeat of students in your room? (P)
684. Does the average heartbeat change with age? (I)
685. What effect do different amounts of activity have on the heartbeat? (P)
686. What is the average heartbeat of different animals? (P)
687. What is the difference between the auricles and ventricles in a heart? Dissect a beef or sheep heart obtained from a butcher. (I)
688. Can you design an artificial heart? (U)
689. Can you observe blood circulating through capillaries? Place the head of a goldfish in a wet handkerchief. Lay the tail of the fish on a black microscope slide. Can you see the lines of corpuscles moving? (P)
690. Can you locate the valves in your veins? Pump your fist open and closed for several minutes in order to make the veins in your arm stand out. Start at your elbow and move your finger along the vein toward the wrist. You will force the blood out of the vein. The vein will be empty from your finger to the valve. (I)
691. How does blood circulate through the body? Can you trace the route? How does blood circulate through different animals? (I)
692. What material is added to the blood, and what material is removed from the blood at different locations throughout the body? (U)
693. Does the heartbeat rate of different animals increase with fear? (I)
694. Does lymph contain white blood corpuscles? Examine the fluid from a blister under the microscope. (U)
695. Why is the circulation of lymph important to the body? (U)
696. What causes swollen ankles if you stand a lot? Why are your hands sometimes swollen in the morning? (I)
697. What part do lymph nodes play in getting rid of bacteria? Can you examine lymph nodes of small animals? What do these contain? (U)
698. Does grasshopper blood contain corpuscles or just lymph? How do grasshoppers get their oxygen? (I)
699. How many hearts does an earthworm have? Are all earthworms constructed the same? (I)
700. Does the blood of earthworms contain red corpuscles? Is the blood red? (U)
701. Can you observe the flow of blood in an earthworm through a microscope? (I)
702. Can you take the pulse rate of a fish? What does the heartbeat sound like? (U)
703. Can you observe the circulation of blood in the frog’s foot? What conditions affect the circulation of the blood? (I)
704. How does a frog’s circulation system operate? (U)
1 If you purchase a microscope, it may already have a plug-in or battery-powered light source. This light source is for microscopes that only have a mirror below the stage. Can you design a modern LED-based apparatus that will work the same way?
2 Possibly. Silver nitrate is still available at some drugstores. See Appendix A for additional material sources.
3 Model cement, Duco cement, or five-minute epoxy.
4 Small glass kitchen prep bowls or ramekins will work well.
5 More commonly at grocery stores, especially Asian or health food stores.
6 Question: What advantages and disadvantages does this micrograph have over a modern USB microscope?
7 Most often, this material is called “Linear polarizing film.”
8 It would be more correct to say that there is a lot to say about how light travels; our understanding of how light travels is not controversial.
10 See Note 1 in Appendix E about working with animals.
11 Originally “acetamine.” Pure acetaminophen may come as powder or crystals. Acetaminophen tablets (and other forms for human consumption) are not suitable for this project.
12 In modern scientific usage, the terms “plant” and “animal” refer strictly to multicellular organisms.
13 And other micro-organisms.
14 Protozoa is a historical classification, no longer in use, that refers to “animal-like” single-cell organisms.
15 Brine shrimp eggs come in a jar of dry granules. They are about the size of sand grains.
16 See “Microscope Slide Making” for more about well slides. Take care not to leave your living specimens on a well-lit microscope stage for too long; they may not be able to handle the heat.
17 It is kinder to use a small transparent pillbox or petri dish with a lid on the microscope so that the animal can be set free later.
18 Alternative method: Melt a small amount of paraffin, in a small beaker in a microwave.
19 If you were to follow these directions as written—and please do not—you might observe that what begins as a simple “harmless” experiment (to see how rats navigate mazes) quickly turns into what could be called an experiment in animal cruelty. This is an excellent illustration of why even “informal” research with animals needs guidelines and oversight. In this and other cases where animals are involved, please carefully read and understand Note 1 in Appendix E.
20 Can you find a way to test this that does not involve starving the animal?
21 Tread carefully here (if at all) and work within animal research guidelines.
22 Under no circumstance go hotter than an electronic “heat stone” from a pet store (the kind designed for reptiles to bask upon).
23 Most fabric stores sell lightweight mosquito netting, which would be perfect for this project.
24 Ethyl acetate is also widely used. Avoid carbon tetrachloride; see Note 21 in Appendix E about it.
25 Many major grocery stores and ice cream shops carry dry ice; you may need to ask for it.
26 Obviously, it cannot burn but instead freezes skin causing frostbite, which is a serious injury.
27 The safest way to perform this experiment is to use a glass-encapsulated mercury switch.
28 You may be able to predict the results. But also think about the cleanup afterwards!
29 Once again, please read Note 1 in Appendix E.
30 Is this a reasonable thing to do to a small animal? One might argue either way. See Note 1 in Appendix E.
31 As we have noted repeatedly, much more care must be taken with animal experiments than in the era when this book was originally published. See Note 1 in Appendix E.
32 Saltwater aquariums are now common. Pet stores that sell them can show you how to build a sustainable environment. What (other than the salt) is different in a saltwater aquarium?
33 This is only enough room for a very small animal. A terrarium should provide ample moving space for the animals within. Consider starting with a 10-gallon aquarium, for all but the very smallest animals.
34 See Note 45 in Appendix E about dissections.
35 A common hobby knife (X-Acto, for example) will also work well.
36 Many mushrooms—even some that look very similar to edible mushrooms—can sicken or kill you. Learn safe mushroom collecting practice from guides or a mushroom club before starting. Never test your results while collecting mushrooms without a 100% positive identification, preferably from more than one source. Consult with an expert (a researcher or professional who works in the field of mycology) when necessary.
37 It should go without saying, but once you begin testing a piece of food with chemicals, you should no longer consider it to be food.
38 Don’t use carbon tetrachloride. See Note 21 in Appendix E.
39 There are several experiments here that seem very hard to justify (this among them). Can you learn what happens in this case by looking up other people’s research on the subject?
40 Many butchers and supermarkets sell blood.
41 This chart is called the Tallquist Hemoglobin scale.
42 Blood typing a classroom of students was once a common activity. Do not attempt to collect biological data or samples from your classmates or colleagues without informed consent (and for minors, parental permission).