Make: The Annotated Build-It-Yourself Science Laboratory (2015)
Part II. Physics
Chapter 2. Astronomy and Light
Purpose: A star chart is used as a map of the sky. It can be set for any hour of any day in the year. With this chart you can predict the position of any star, planet, constellation, comet, or satellite.
Materials: A star chart, either store-bought or you can make one yourself.1
You may make a large-size star chart, if you have one for a pattern, by using the following material: one large piece of black cardboard, a second piece of cardboard of a lighter color, silver or white paint, and the use of an opaque projector.2
What to Do: You can make a direct copy of a star chart by removing the inside black star sheet and tracing with tracing paper. The dots for stars can then be transferred to your black cardboard. You then trace the outer cover. Mount your star chart on a piece of plywood and use a thumbtack in the center of the black star dial so the dial will turn. Your stars will stand out better if you use silver or white paint.
A second way to make a star chart is to use an opaque projector. Place the sample black dial in the projector and project the larger image on the wall. Fasten your cardboard on the wall and mark the spots or stars on your cardboard with a pencil. You can paint them later. Copy the outside cover in the same manner. This enlarged star chart can be mounted on a bulletin board with a single tack through the center of the dial. The chart could also be mounted on plywood.
Operation of Equipment: Your star chart has four corners. Hold the corner marked NORTH up. Notice the time of day right under the word NORTH. To the right of MIDNIGHT is 11 PM, 10 PM, etc. Eight o’clock is a good time to watch the stars, so turn the black dial so that the month and day is exactly over the correct hour. You have now set the chart to show you the position of the heavens at 8 PM this evening
Now turn the whole chart, depending on the direction you wish to look. If you are looking north, place the corner marked NORTH down. The stars you see on the lower edge of your chart are the stars just above the horizon. As you look toward the center of the chart, the stars you see are those higher in the sky. The ones in the center of the chart are those directly overhead. Can you find the Big Dipper (Ursa Major)?
If you wish to locate stars in the southern sky, place the corner marked SOUTH down. Again, the stars near the lower edge of the circle are those just above the horizon. As you look toward the center of the chart, the stars are found higher in the sky.
In the same manner, if you wish to look east, you would place EAST down, and if you wanted to study the western sky, you would place the corner marked WEST down.
The larger dots show you the brighter stars. By using these bright stars as signposts, you can locate all the constellations in the sky. Notice that some of these larger dots have a Greek letter by them.3 If you look on the back of the chart, you will find the name of the star in that constellation and also the brightness or magnitude of the star.
In order to locate planets, look at the bottom on the back of the chart.4 You will see the four planets mentioned: Venus, Mars, Jupiter, and Saturn. Use the chart for the correct year. By using the month of the year and the name of the planet, you will find the name of the constellation that the planet is either in or near. The abbreviation of the constellation is usually given. To find out the full name, look at the list of abbreviations.
In order to locate the planet, look around the outer edge of the circle for the constellation. All planets are found very close to the horizon. If the planet is visible for the hour you set your chart, the constellation will be within the black circle. Notice the direction of the constellation on your star chart. This is the direction in which you would look for the planet.
To help you recognize the planets, here are some tips: Venus is exceptionally bright, the brightest object in the sky except for the sun and the moon. Jupiter is very bright and white. Saturn is dull, greenish-yellow, and found near Jupiter.5 Mars is bright and red.
Can You Work Like a Scientist?
1. Hold the chart over your head. Turn the dial around once. This is what happens to the sky each complete day. Do the stars seem to move? What is the real cause of this movement?
2. Locate the Big Dipper. Hold your chart with NORTH down. Rotate your star chart for one complete day. What happens to the Big Dipper? Does the Big Dipper ever disappear from sight? Can you find other stars that are always in view? Where are these stars located?
3. Where is Polaris, the North Pole star, located on the chart? Why does it seem not to move when all other stars do move?
4. Would your chart be accurate for every place on Earth?
5. Have other stars been our North Pole star during the history of the Earth?
6. Is there a South Pole star for people living in the Southern Hemisphere?
7. Are all stars in the Big Dipper single stars? Look carefully at the stars in the handle of the Big Dipper. You will need either a telescope or a pair of binoculars.
Purpose: A telescope can be used for many purposes. A simple telescope can be used for viewing craters on the moon, the four largest moons of Jupiter, and the rings of Saturn. It is also excellent for observing sunspots. Never look at the sun directly. Never look directly through a telescope at the sun. The light can damage your eyes and perhaps blind you! (See “Sunspot Viewer”.) A telescope can also be used for observing objects in nature, such as birds and animals.
Materials: Two convex lenses,6 a mailing tube or toilet paper roll, cardboard, rubber cement, and paper.7
What to Do: Find the focal length of your lenses. This can be done by focusing the rays of the sun or the light from a ceiling light on a piece of paper. The distance from the lens to the paper is the focal length. This will help you know how long you must make your telescope. The length of each tube should be longer than the focal length of the lens. First, mount the lenses. Cut a round hole in a piece of cardboard. Glue the lens to the cardboard with the cement. You will want to mount the smallest lens8 in the mailing tube. Place the end of the tube on the cardboard. Center the lens and then trace around the end of the tubing. Cut the cardboard just inside the line so the cardboard will just fit in the end of the tubing. Glue the cardboard lens holder in with cement. Now to make the slide tube, wrap one sheet of paper around the tubing, fastening with Scotch tape. Wrap a second sheet over the first sheet and fasten with Scotch tape. Slide both sheets off the tubing and remove the inside sheet. The outside sheet can be used for your slide tube and will just fit. Mount the holder of the second lens in the end of the paper tubing with cement. Slide the two pieces of tubing together, and your telescope is completed. You can shorten the slide tube by cutting the paper with scissors.
Operation of Equipment: The eyepiece of your telescope is the end with the mailing tube. Look through this end and sight on a book or sign at the other end of the room. Move the slide tube back and forth until the object comes in focus.
Can You Work Like a Scientist?
1. Is the object that you see upright or upside down?
2. Turn the telescope around and view from the other end. Is there any change?
3. Refracting means bending. When light goes through glass, the glass is thicker than air, and part of the light is slowed down. Part of the light from the object then is traveling faster than the other part. The object seems bent. Can you test this theory by using water for your lens? Fill a glass with water. Place a pencil in the water. Can you find a position where the pencil seems to be bent? Does the water seem to slow down or speed up light? Can you try other liquids and see if light bends more or less than in water?
4. Light bends more going through some things than others. Does the angle the light enters the object have anything to do with the amount of bend?
5. Could you measure the amount of bend? Could you compare the amount of bend? This is called the refractive index. Can you find out more about different materials bending light?
6. Galileo made a telescope similar to yours and discovered many things. Find out more about the work of Galileo. Perhaps his work will suggest other uses for your telescope.
7. Sir Isaac Newton bent light rays with a prism to find out what the rays of light were made of. Can you break light up by using a mirror and a pan of water?
8. Can you measure the power of your simple telescope? Try to think of a way to tell how many times your telescope enlarges what you see. Galileo’s telescope was only 25 power.
9. Fill a sink or bathtub to a depth of several inches. Make waves by dripping water into the sink or tub. Can you arrange the light so you can see the shadows of the waves? Can you make the waves bend? These rays are very similar to light waves.
10.From the drawing, can you see why a convex lens bends light?
Purpose: This instrument is used to examine light. The light from a star can give us a clue as to what the star is made of. This instrument can also be used to examine light from burning objects on Earth. The colors given off through the spectroscope give a clue as to the make-up (composition) of the object.
Materials: Cardboard mailing tube or roll from toilet tissue, diffraction grating.9
What to Do: Cut a small slit in a piece of cardboard. Glue this piece to the end of the mailing tube. Trim the edges of the cardboard so that the piece just fits. Glue your diffraction grating to the other end. Before you fix the diffraction grating in position, be sure it is turned the way you want it. Read how to operate the spectroscope below. Then you will know if the grating is turned correctly.
Operation of Equipment: Point the end with the slit at a bright light. Look through the end with the grating. Don’t look directly at the slit, but off to the side. If the diffraction grating is turned right, you should see the colors that make up the light.
Can You Work Like a Scientist?
1. Would the spectroscope work if you didn’t have the slit at one end? Why does the slit help? What would happen if you made the slit in the form of an X?
2. What happens to the colors as you turn the grating?
3. What does the grating say about the lines on it? How many are there? How does this help to break up the light?
4. What are the colors of the spectrum of sunlight? Can you see these in your spectroscope? Are the colors always in the same order? Is this the same as in a rainbow? What in a rainbow works as a diffraction grating?
5. Use your spectroscope on a candle, regular light bulb, and on a fluorescent light. Are the spectrums the same? What colors are different?10
6. On a bright moonlight night, find the spectrum of the moon. Is this the same as the sun? Why doesn’t the moon give off a brighter spectrum?
7. What are the problems of examining the spectrums of distant stars?
8. What is the spectrum (colors) of different chemicals when they are burned in the flame of an alcohol burner?
9. You can use the diffraction grating to project the spectrum on a wall or screen. Punch a hole in a piece of 2” × 2” cardboard and then place this cardboard slide in a slide projector. Hold the grating at a 45° angle in front of the beam of light.11
Purpose: The astrolabe is used in navigation and astronomy to sight and record positions of stars. It can be used to find the latitude and the bearing of a star.
Materials: Wooden base, 2” × 2” wood upright, small piece of tin or cardboard for pointer, a protractor, and a soda straw or piece of glass tubing for the sighting tube.
What to Do: Glue the pointer to the bottom of the upright. Use the protractor and draw on the cardboard a circle of 360°. Glue this cardboard on the wood base. Fasten the upright to the base with a screw. Glue the straw or glass tubing to the protractor. Fasten the protractor to the wood upright by means of a screw. Tie a piece of string to the screw and hang a weight on it. This string will help you level the astrolabe and also serve as the pointer to tell you the number of degrees of elevation.
Operation of Equipment: Sight the North Star through the tube. Turn the base so that the base says 0°. Now sight any other star or object in the sky. The protractor and string line show the angle of elevation (how high the object is in the sky). The number of degrees you turn the sighting tube from true north is shown by the number of degrees the pointer moves from 0°. This shows how many degrees east or west the object is from true north.
Can You Work Like a Scientist?
1. Take readings of the North Star at different times and on different days. Are the readings always the same?
2. Take readings of a star in the Big Dipper. Are these readings always the same? Why?
3. Take readings on the moon at a certain time each evening for a week. What can you say about the path of the moon?
4. Can you plot the path of the moon across the sky by your readings? Will it follow this same path one month later?
5. Sight on the North Star. Is this true north as shown on your compass?
6. Take the readings on the sun during a day. Can you plot the path of the sun across the sky? Is it the same as the moon? (Don’t look directly at the bright sun. See “Sunspot Viewer”.)
7. Are the readings of the sun exactly the same at the same times day after day? Why would this be?
8. From some spot in the room take a reading on the clock. Have a classmate who was not in the room try to figure the spot from which you took the reading. Try this on the playground. (Use your compass to find north.) How would this help you to navigate a ship?
Dip Circle Meter
Purpose: This instrument is used to measure the angle of dip or angle of inclination at different places around the Earth. Since the needle points toward the magnetic pole, this instrument can be used to determine latitude. The greater the dip from the horizontal position the farther north a person is located. At the North Pole the needle would dip straight downward.
Materials: Wood for frame as shown, two glass slides, two rubber bands, protractor, two steel knitting needles, and a cork.
What to Do: Build the U-stand as shown. Glue the protractor on one end of the stand. Glue the microscope slides to the wood supports. Magnetize one of the knitting needles either by rubbing the needle with a magnet or by placing the needle in a solenoid coil (see “Solenoid”).
Insert the non-magnetized needle through the cork to serve as an axle. Insert the magnetized needle as shown. Place the axle needle on the ends of the glass slides and let the needle turn freely.
Operation of Equipment: The needle is attracted to the poles of the Earth. In the Northern Hemisphere, the north-seeking end of the needle will point toward the North Magnetic Pole. If you are at the equator (0° latitude), the needle will point horizontally or parallel with the Earth. The angle of dip is zero. As you move farther north, the needle points more and more vertically. When you cross the 45th parallel, the dip circle meter is pointing at a 45° angle as compared with the protractor. Therefore, for every degree north you move, the angle of dip increases one degree.
Can You Work Like a Scientist?
1. If you were over true north, would the dip circle needle point straight down?
2. If the needle did not point straight down, what would you conclude?
3. Where on Earth would the needle point straight down?
4. The Earth’s magnetic poles are constantly moving. At one time the North Magnetic Pole was over the state of Oregon. Scientists can tell this by examining the remains of adobe fireplaces built by Indians12 long ago. The bricks contained bits of iron. When the bricks were fired, the magnetic material became fixed as a permanent magnet pointing toward the Magnetic Pole. How can you account for the fact that these fine compasses don’t point at the Magnetic Poles today?
Purpose: This sundial shows the season of the year, sunrise and sunset, and the hour of the day when the sun is shining. You can use this sundial to show the effect of the sun’s rays on any spot on the Earth.
Materials: Large ball or globe of the Earth, a base to hold the ball or globe.
What to Do: If you are using a large ball, trace on the ball the outline of the continents and other features of the Earth. If you are using a globe, use the type that sets in a round circular base. In order to make such a base, cut the top and bottom off a one-pound coffee can. Set your globe sundial outdoors where the sun will shine directly on it. The globe is an exact copy of our Earth. When lined up properly, the spot where you live will be on the top side of the globe.
In order to line the globe up properly, turn the North Pole of the globe in the direction of North. At twelve noon, notice the angle of the shadow cast by a stick that is straight up and down. The axis of your globe should be set at that same angle.
You can check the position of your globe by setting the axis to point directly at the North Star on a clear night.
After you have set your globe at the correct angle, rotate the globe (east or west) so that the spot on Earth where you live is on the top side of the Earth. The sun should fall directly on the longitude lines that run through your town (or close to it).
Operation of Equipment: After you have set your globe, fix it so that it cannot turn. The globe can be covered at night. If the globe is not disturbed, you can observe the seasons of the year, the changing angle of the sun throughout the year, difference in sun time at any time on the Earth, the speed of rotation of the Earth, and even the light as cast by the different phases of the moon on our model Earth. In order to observe the changes for a complete year, you must make regular observations for that length of time.
Can You Work Like a Scientist?
1. How many degrees does the Earth turn each hour?
2. Could you make a time clock and attach it to the top of your model Earth?
3. What part of the Earth has the longest day? The shortest day? Can you predict sunrise and sunset at different locations around the Earth?
4. Are the seasons of the year the same in the Southern Hemisphere as in the Northern Hemisphere?
5. What days of the year do we have an equal amount of daylight and darkness? Can you predict this? Is this date the same throughout the world?
6. When the sun is shining brightly, use a thermometer and take the temperature at various places on your model Earth. Can you see why the angle of the sun produces the seasons on Earth?
7. Can you tell at what spot the sun is directly overhead on your model Earth? This would be the spot where there would be the shortest shadow.
8. Can you use this idea to plot the path of the sun as it seems to travel around the Earth? Does the sun really move around the Earth?
9. Could you use a flashlight or a light bulb inside a room to demonstrate how the universal sundial works?
10.Make a tripod as shown. You can use this tripod to show the exact spot on Earth where the sun is shining directly overhead. The spot where the pin does not cast a shadow is the part of the Earth that directly faces the sun.
11.Could you use a sundial of this type for navigating a ship?
Planetarium Model of the Solar System
Purpose: This planetarium produces the motion of the planets in their orbits around the sun. The motion of the moons around their host planet, as well as the rotation of the planets, can be shown with this model Solar System.13
Materials: Large wooden rod about two inches in diameter and two feet in length, old playground ball (rubber) about 6” in diameter, wood for the base, a long nail, coat hangers, and clay or styrofoam balls for the planets.
What to Do: Drill a hole into a piece of 2” × 6” wood. The hole should be the same size as the wooden rod. Cut off the top four inches of the wooden rod. Glue the remainder of the rod into the hole. Be sure the rod is straight up and down. Nail the 2 × 6 to the larger wooden base. Drill a small hole into the short piece of rod about an inch deep. Carefully drive the nail into this hole. Cut off the head of the nail.
Drill a hole into the top of the larger upright rod. The hole should be deep enough and large enough so the nail can turn easily in the hole. Next cut a small hole in the top and bottom of the rubber ball and slip the ball over the wooden rod. This represents the sun.
Drill holes in the short top wooden rod and insert coat hanger wires. These wires will be of different lengths depending on a planet’s distance from the sun. These wires should balance each other.
Paint your sun with two or more coats of yellow enamel paint. Make your planets of papier-mâché, styrofoam, or clay. Since Jupiter would be quite heavy, use a ping-pong ball for such a large planet and coat with clay. You may insert dressmaker pins (pins with large colored heads) for the moons of the planets. Hang the planets from the coat hanger with black thread.
Operation of Equipment: Place a tack in the top of the short wooden rod and tie a piece of thread to it. Wrap the thread around the short rod several times. Pull on the thread, and your model Solar System should revolve around your sun. To make a planet rotate, twist the thread on the planet. The planet then will rotate as the planets orbit the sun.
Can You Work Like a Scientist?
1. Do all of the planets normally move in the same direction and on the same plane?
2. How many times would you wrap the thread around the rod to represent your lifetime? What would happen if all of the planets speeded up in their path?
Purpose: A planetarium projector is made by shining a light through small holes in a round cover that goes over the light. The spots are then shown on a ceiling or dome and resemble the stars at night.
Materials: An old umbrella and a star chart or a book about stars showing star patterns.
What to Do: The cloth of the umbrella represents the dome-like sky. Punch small holes with a pin or nail to represent the stars. Use your star chart so the holes will be in the proper positions to represent various stars and constellations. Perhaps it would be best to layout your sky before you punch the holes by using chalk and placing dots on the umbrella for stars. The center of your umbrella should be the North Star. Small holes should represent faint stars. Larger holes should represent the brighter stars. If possible, paint the inside of the umbrella with flat black paint.
Operation of Equipment: Hold the umbrella over your head. The lights should be out and the shades drawn so the room is dark. There should be a light over the umbrella. As you look up through the umbrella, you should see the stars as they appear overhead. Slowly turn the umbrella. The stars will seem to move across the sky.
Can You Work Like a Scientist?
1. Which way do you turn the umbrella, left to right, or right to left in order to imitate the movement of the stars across the sky?
2. Does the sky really move?
3. If you were turning the umbrella with the movement of the Earth, how long should you take to make one complete turn of the umbrella?
4. Which stars seem to move the most? What is the location of stars that seem to move the least?
5. If you hold the umbrella directly overhead, from what position on Earth would you be viewing the stars?
6. How would you hold the umbrella to show the stars at your latitude?
7. How would you hold the umbrella to show the stars as you would view them from the equator?
8. What does the handle of the umbrella represent?
Purpose: A planetarium projector is used to project spots of light representing stars on a dome or ceiling.
Materials: Large rubber ball, flashlight bulb and socket. As a substitute for the ball, use a large balloon and papier-mâché materials.
What to Do: Cut out a small hole in the bottom of the ball. Drill holes in the ball to represent the stars. Place the ball over the flashlight bulb and socket. Connect the flashlight bulb up to the power supply or battery.
A second type of projector can be made by using a balloon as a form. Inflate the balloon and then cover the balloon with several layers of newspaper strips soaked in wheat paste. After the papier-mâché strips dry on the balloon, remove the balloon by deflating it. Cut out part of the bottom of the papier-mâché ball and insert the bulb. Drill or punch small holes in the ball to represent the major stars and constellations. The bulb is fastened in the bottom of the ball. The North Pole Star should be punched directly over the bulb at the top of the ball.
Operation of Equipment: As you turn the ball, the “stars” seem to move or rotate on the ceiling and side walls. Since you rotate the ball around the North Pole Star, this star seems to stand still while the stars farther down on the ball (south) seem to move very rapidly. When these stars seem to make one complete trip around the North Pole Star, one day and one night is completed.
Can You Work Like a Scientist?
1. Can you turn the ball so as to show the North Pole Star and constellations in the same position as they normally appear at your latitude?
2. As you move farther south, how would the position of the North Star seem to change?
3. Can you find out how the position of the stars can be used for navigating ships and planes?
4. At your latitude, what stars never seem to set, but can be seen throughout the year?
5. Can you use your planetarium to show the stars at the different seasons of the year?
Purpose: The Foucault pendulum is used as a proof that the Earth rotates, or turns on its axis. This model pendulum shows the principle that the French scientist, Foucault, used back in 1851 to prove that the Earth does rotate.
Materials: Three clothes hangers, cork, button, marble, thread, cake tin or metal lid to a round candy tin, and a phonograph.14
What to Do: Cut and straighten the coat hangers so that you have three pieces 18 inches in length. Force a hole through the cork with a nail. Insert a thread through the hole. Fasten a button on the top side of the cork and glue a marble to the other end of the thread. Insert the top ends of the coat hanger wires in the bottom of the cork as shown. Fasten the other end of the coat hanger wires to the edge of the cake tin with Scotch tape. Drill a hole in the center of the cake tin so that the tin will fit on a phonograph turntable in much the same way as a record.
Operation of Equipment: Place the cake tin and pendulum apparatus on a phonograph turntable. Start the pendulum swinging back and forth. Then turn on the phonograph so that the turntable rotates. The rotation of the turntable is similar to the rotation of the Earth except that it is greatly speeded up.
Can You Work Like a Scientist?
1. Start the pendulum moving back and forth before you turn on the phonograph. Does the pendulum seem to follow the same path or does it change directions?
2. Time how long it takes for the pendulum to make one full swing. Does it take longer to make a long swing of the pendulum than it does to make a short swing? Why is this constant time period of a pendulum swing helpful in designing a clock?
3. If you increase the length of the cord or thread, do you increase or decrease the time for one complete swing?
4. If you shorten the thread or cord, do you increase or decrease the time for one complete swing of the pendulum?
5. Can you experiment and determine the length of thread necessary in order for the swing to take exactly one second?
6. Would the time it takes for the pendulum to make one swing be affected by changes in altitude or different positions on Earth?
7. Start the pendulum moving and then turn on the phonograph. Does the pendulum change directions when the platform beneath the ball turns?
8. If the platform represents the turning Earth, how does the Foucault Pendulum prove that the Earth turns? What would happen if the Earth did not turn?
9. Will the pendulum gradually slow up? Why? Could you design an electromagnet that could keep the pendulum moving?
Purpose: The sunspot viewer is used to protect the eyes when looking at the sun. Never look directly at the sun with either a telescope or your eyes alone. The sun is so bright that it can blind you. The effects from looking directly at the sun sometimes show up years later.
Materials: A dark exposed negative (one that was overexposed and is almost completely black) or a smoked piece of glass15 and a shoe box.
What to Do: Cut a square hole in the end of the box. The hole should be smaller than the negative. In the event you are using smoked glass instead of the negative, hold the clear glass over a burning candle. The incomplete burning will deposit carbon on the glass. Tape the negative or smoked glass to the inside of the box over the square hole. Cut a small viewing hole in the other end of the box.
Operation of Equipment: Again, don’t look directly at the sun. Be sure when you view the sun to look through the shoe box filter. The negative or smoked glass should dull the appearance of the sun and enable you to view the sun without harm to your eyes. Caution: If the sun appears bright through your viewer, look away quickly. Your negative or smoked glass is not dark enough. You should be able to see dark spots on the sun. These are called sunspots.
Modern Safety Practice
Protecting your eyes is a serious concern. For directly viewing the sun, you need to use a special type of dark filter—not just smoked glass or sunglasses. Use a #14 (or darker) welding shade or purpose-built solar viewing film. See Note 13 in Appendix E for extended discussion.
Can You Work Like a Scientist?
1. What are these sunspots? What causes them?
2. Are these spots always in the same place from day to day?
3. Could you keep a record of sunspots over a period of time? What relation do the sunspots have to weather conditions?
4. Are sunspots really storms on the sun? Read about what was found out during IGY (International Geophysical Year).
5. Could you use your sunspot viewer to take a picture of the sun with your camera?
6. Does the size of the sunspots change from day to day?
7. Does the sun turn (rotate), or do the sunspots move around the sun?
8. In which direction do the sunspots move? Do all the spots seem to move in the same direction? Why?
9. Are the sunspots related to the “northern lights” and magnetic disturbances that upset radio communication?
Moon Range Finder
Purpose: The moon range finder is used to determine the relative distance of far-off objects, such as the moon, distant buildings, mountain peaks, and ships far out at sea.
Materials: Yardstick, 3” × 5” file card or tin.
What to Do: Cut a slit in the piece of tin or file card large enough so that the tin or cardboard can slide easily back and forth. Cut a second slit about half an inch high and a quarter inch wide.
Operation of Equipment: In order to understand how your moon range finder works, try this simple experiment. Hold out a pencil at arm’s length. Sight a distant object and compare the apparent height of the object with the pencil. Now move the pencil closer to your eye. Notice that the object seems to get smaller as compared with the size of the pencil. The size of the object didn’t change, but its apparent size as compared with movable object (the pencil) did. Your moon range finder works on this principle. The distant object to measure can be the moon. The movable object or point of reference is the hole in the file card.
Hold the yardstick up until it touches the cheekbone under your eye. Sight through the slit in the file card on some distant object such as the moon. Move the file card back and forth until the size of the moon just fills the vertical slit in the card. Notice on the yardstick how far the card has to be held from your eye.
Try the experiment again. Does the card have to be held at the same distance from your eye in order to fill the hole in the file card? If the moon were larger, would you have to move the file card toward your eye or farther away? What if the moon were smaller?
You can make a scale of distances on your yardstick by using objects of a known or easily measured distance as a comparison. For objects close by, have a person hold an object a known distance from your eye. Move the file card back and forth until the object just fills the hole in the card. Mark on your moon range finder the distance in feet. Have the person move away. Repeat the operation for the new distance.
Can You Work Like a Scientist?
1. The moon appears to be larger when it first rises and gets smaller as it moves overhead. Does the moon change in size during the evening? Remember, if the distance the card is held away from your eye doesn’t change, the size remains the same. If the moon increases in size, you must move the card closer to your eye in order to fill the hole.
2. Does the moon change in size at different periods of the year such as during the harvest moon?
3. Does the moon change in size during the phases of the moon?
4. Is the moon always the same distance from the viewer? Assume in this case that the moon does not change in size.
Water Faucet Vacuum Pump
Purpose: This vacuum pump is available any place there is a water faucet. With this simple pump you can conduct many experiments requiring a low air pressure.
Materials: Cork glass T tube (see “T Tube”), one-hole rubber stopper to fit opening in faucet, rubber tubing, and a bell jar.16 For the bell jar you can use either the wide-mouth gallon jar or a regular gallon jug.
What to Do: Connect the T tubing to the rubber stopper as shown. Slip the stopper tightly into the faucet. Connect up the vacuum jar to the T tubing with rubber tubing.
Operation of Equipment: Turn the faucet on slowly. Then open the faucet up. Be sure to hold the stopper in place. The pressure of the water going through the T tube will suck the air from the bell jar. In order to close off the bell jar, pinch the rubber tubing.
Vacuum Jar Pressure Gauge
Purpose: This mercury pressure gauge enables you to measure the amount of air pressure remaining in the jar. Since air pressure decreases with altitude, the pressure reading can be compared with altitude by using the chart.17
Materials: Two 3’ pieces of glass tubing, short piece of rubber hose, meter stick or ruler that is marked off in both inches and millimeters, wood for support, and about 2 oz. of mercury.
What to Do: Bend the glass tubing as shown. Connect the bottom pieces together with rubber tubing. Fasten a meter stick to the wood support. The 1000-millimeter mark should be down. If you do not have a meter stick, use a piece of tape for a scale. Mark a scale on the tape using a plastic ruler which is marked in millimeters. Call the weatherman and ask for the barometric pressure reading in millimeters.18 Pour the mercury into the tube until the mercury reaches this mark on the scale. The height probably will be somewhere between 650 and 750 millimeters. In pouring the mercury, be sure that you don’t touch it. It can be a deadly poison if it gets into your body through a scratch or a cut. Use a plastic funnel thistle tube for pouring.
Modern Safety Practice
For health reasons, mercury is no longer considered safe to work with. Please see Note 26 in Appendix E for discussion.
Operation of Equipment: Connect the bent end of the glass tubing to a vacuum jar as shown. As the pump draws the air out of the jar, the normal air pressure pushes down the mercury in the open glass tubing. The mercury rises in the other tube as the air is withdrawn. See how high the mercury climbs and then note the number of millimeters on the scale. Compare with your chart for an altitude reading. (These are approximate readings.)
Millimeters of mercury
Altitude in feet
Can You Work Like a Scientist?
Can you use the principle of the vacuum jar pressure gauge in making a mercury barometer? See the section on meteorology (Chapter 7).
Purpose: The vacuum pump is used to withdraw air from vacuum jars and other containers in order to conduct various experiments concerning air pressure, altitude effects, and various biological research projects.
Materials: Tire pump,19 rubber tape, 5” piece of 7/16” plastic garden hose, 2” piece of glass tubing.
What to Do: Unscrew the cap off the top of the pump. Remove the inside of the pump. Unfasten the screw and turn the rubber plunger over. Tighten the screw and insert the handle and plunger back into the outside case of the pump. Unscrew the hose and valve. You will reverse this valve later.20
Cut off the screw cap at the end of the tire hose with a razor blade. Then cut off about five more inches so you have a short piece of tire hose. Insert a short piece of glass tubing into the longer hose. Wrap rubber tape around the other end of the glass tubing and force the tubing into the hole in the base of the tire pump. Slide a short piece of 7/16” plastic garden hose over the valve and over the rubber tire pump hoses. Insert a short piece of tire hose into the other end of the plastic hose. You can then slip this hose over glass tubing to make connections on a bottle.
Operation of Equipment: When you pull up on the pump, air is drawn into the pump. When you push down, the valve closes in the pump, and the air is pushed out around the sides of the gasket and out the top of the pump. Remember, seal up any leak that shows up in your hose, etc., or air will leak in from the outside.
Modern Safety Practice
Wear safety glasses when working with a vacuum pump. Not every vessel is designed to withstand a vacuum. What happens if you pull a vacuum on an empty 2-liter plastic soda bottle? Can a glass bottle respond the same way?
Can You Work Like a Scientist?
1. How much of a vacuum can you produce? Use a pressure gauge. Be sure you have tested your bell jar with a regular vacuum pump before you try this. Can you improve the efficiency of your pump?
2. What effect on plant growth does altitude have? What plants will grow at higher altitudes? (Reduce the air pressure with your pump.)
3. If the amount of air on Mars is about equal to that present on the top of Mount Everest (altitude about 30,000 feet), what plants might grow on Mars?
4. At what altitudes can clouds form? See your cloud jar (“Cloud Jar”).
5. What animal would be the best space traveler and withstand a drop in air pressure? Try frogs, fish, worms, rats, etc.21
6. What happens to fish in a fishbowl or jar with reduced air pressure?
7. Will your alcohol burner continue to burn in your vacuum jar as air is removed? At what altitude will the burner go out?
Vacuum Jar—Bell Jar
Purpose: A vacuum jar is used for carrying out experiments that require a different atmospheric pressure or much less air than is normally available.
Materials: Block of ¾” wood, rubber sink stopper, wide-mouth gallon jar,22 a one-hole rubber stopper, and glass tubing.
What to Do: The block of wood should be larger than the opening of the jar. Drill a hole in the center of the block to fit the size of your rubber stopper. Glue the rubber stopper to the wood block. Cut a hole in the stopper to match the hole in the wood. Insert the rubber stopper and a short piece of glass tubing as shown.
Operation of Equipment: The bell jar can either be used upright or tipped upside down. Grease the rubber sink stopper with heavy lubrication grease (from a service station). You can try vaseline, but it is sometimes too thin.23 Set the jar on the board base. Connect the glass tubing to a vacuum pump with rubber hose. In order to close off the jar and remove the pump, you can either install a valve in the rubber hose or bend the rubber hose and clamp the end. The clothespin adjustable clamp will also serve as a clamp to seal the hose.
1. Some jars are thicker in one place than another. Therefore, thoroughly test your wide-mouth gallon jar by connecting the jar to the vacuum pump and then completely covering the jar with a metal waste paper basket, or a strong wooden box, etc. The jug might implode if it is weak in one spot. Draw as high a vacuum as your pump will permit in your test. The safest method would be to have the pump (and all people) outside a closet, the jar inside, and the tube running under the closet door.
2. When in use, don’t draw a full vacuum unless you set up adequate safety provisions. Use of a pressure gauge is very helpful (see “Vacuum Jar Pressure Gauge”).
3. Allow the air to return into the bottle before you attempt to open the jar. Otherwise, the air will rush in with tremendous force and this sudden force might break the jar.
Modern Safety Practice
Recall that it only takes a small scratch and some pressure to break glass (“Cutting Glass Tubing”): Don’t scratch the glass of your bell jar.
See Note 2 in Appendix E for additional notes about safety practice around glass that may break.
Purpose: A solar furnace is used to focus the sun’s rays and thus produce a high degree of heat upon a small area.
Materials: A headlight reflector or an old umbrella.24
What to Do: If you use an umbrella for your solar furnace, the inside surface of the umbrella should be covered with aluminum foil. Care should be taken that the foil is spread on as smoothly as possible. The foil can be glued or stitched to the cloth surface of the Umbrella.
An old headlight reflector can also be used to make the solar cooker or furnace. The shiny surface should be polished.
Operation of Equipment: You will need to build some kind of stand to support your furnace. The furnace should be pointed toward the sun or some other source of light. The rays of light strike the curved surface and are reflected to one spot. At this spot all the rays converge or come together. This is the focal point.
If you are using an umbrella, the handle can be cut off just before this focal point. Objects to be heated can then be placed near or attached to the remaining part of the handle.
Modern Safety Practice
1. Keep your eyes (and other body parts) away from the focal point at all times.
2. A solar furnace can potentially start a fire. Just in case, keep a fire extinguisher handy, and don’t leave the furnace unattended in sunlight.
Can You Work Like a Scientist?
1. Can you determine the focal point of your umbrella furnace? Move a thermometer back and forth until you find the point where the most heat is generated. You may have to use a candy thermometer if the heat is greater than that which can be measured with a regular household thermometer. Be careful that the heat doesn’t cause the liquid in the thermometer to break it.
2. You can use your solar furnace to determine the degree of heat given off by the light from the sun. How does this heat vary throughout the year?
3. Can you boil liquids and melt certain solids with your furnace?
4. Can you design a furnace in which you use a lens to focus the rays on a very small area? How hot can you get the point?
5. If you had a larger surface from which you could reflect the sun’s rays, could you increase the temperature at the focal point?
Solar Distillation Apparatus
Purpose: One of the greatest problems scientists face is that of securing enough fresh water for drinking and irrigation purposes. The solar distiller uses the energy of the sun to remove the salt from sea water and thus provide fresh water.
Materials: Cake tin, one pane of glass slightly longer than the cake tin, a second pane of glass several inches longer than the first (you can determine this length when you start to build your distiller), black paint, and a tray to collect the distilled water.
What to Do: Paint the inside of the cake tin with black paint. Also paint the shorter of the two pieces of glass black on one side. Support the glass as shown in the drawing by cementing the glass to a block of wood with rubber cement. The longer piece of glass is fastened to the top of the short piece with masking tape so that the two pieces of glass will hinge and fold together. When the apparatus is set up, the long piece of glass is raised slightly above the cake tin by gluing matchsticks25 to the glass. A tray is placed under the edge of glass that projects beyond the cake tin. This tray is used to collect the distilled water.
Operation of Equipment: Salt water (mix salt and water in a quart jar) is added to the cake tin. As the sun’s rays pass through the glass pane, the water is heated and begins to evaporate. The vapor strikes the bottom of the slanted pane and condenses. The drops of water flow down the inside of the glass into the tray.
Modern Safety Practice
1. You can cut the glass to shape for this project; see “Glass Cutter”. Whether or not you cut your own glass, remember that glass edges are very sharp. As described in that project, you can sand the edges off glass under water.
Can You Work Like a Scientist?
1. Why should you paint the inside of the cake tin and the vertical glass pane with black paint?
2. Can you determine the rate (pints per hour) at which your solar distiller produces fresh water?
3. Is the water collected really free of salt?
4. What areas of the Earth would be helped if a cheap method of distilling sea water could be developed? Could crops be grown in an irrigated desert?
5. How can you speed up the rate of distillation?
6. If you closed in the sides of the still, would this increase the rate of distillation?
7. Could you design a portable distillation apparatus that could be used by people stranded on life rafts in the ocean?
8. Can you distill sea water? Is sea-water salt the same as the salt we buy in stores?
9. Is the salt in your tears the same as the salt from the ocean?
Purpose: A constellarium is used for projecting the image of constellations so that the shape of the constellation can be studied.
Materials: Wood for box, base for light bulb, 60-watt bulb,26 cord, and cardboard blanks.
What to Do: Build a long box with slots so that pieces of cardboard can be inserted in the slots. At the far end of the box, a base for a light bulb should be fastened. A small hole should be cut in the near end of the box so that the viewer can look toward the card and the light on the other side of the card.
Operation of Equipment: Black art paper is glued on one side of the cards. Holes are then punched with various sized nails, pins, etc. to represent the stars in a particular constellation.
The card is placed in the slot in the box. The viewer looks through one end of the box and sees the pinpoints of light coming through the holes punched in the card. These pinpoints of light represent the stars in a particular constellation.
Can You Work Like a Scientist?
1. Stars are rated according to brightness or magnitude. The lower the number of magnitude the brighter the star. Can you select a nail to represent each order of magnitude?
2. If you rule off each card into small squares, these squares could represent distances in the sky. As an example, one square could represent the distance in the sky covered by the width of one thumb held at an arm’s length away from you. Using such a scale, could you accurately place the stars in a constellation on a constellation card? You will have to record the distances at night by using your thumb and measuring the apparent distances between the stars in the constellation. Perhaps your thumb might be too large as a measuring unit. Could you use something smaller?27
3. Ancient people imagined the constellations formed pictures in the sky. Can you trace around the holes in the card and form the imaginary figures for each constellation?
Problems to Investigate in the Study of Astronomy and Light
1. Can you determine the time it takes for each of the moons of Jupiter to make one complete revolution around it? Observe the moons through a telescope.28 Make drawings of the positions of the moons each night. (I)
2. Can you classify the major stars in the sky as to their color? How can you tell a red star from a white star? (U)
3. How do the position of the stars vary from night to night? Can you measure the change in position of certain stars over a period of a month? (I)
4. Do sunspots all move at the same rate of speed across the sun? WARNING-Be sure you do not look directly into the sun. See “Sunspot Viewer”. (I)
5. Can you take pictures of falling meteorites? Set your camera on time lapse.29 You should be able to catch the streaks of the meteorites on your camera. (U)
6. If a nut were loose on the outside of your spaceship, could you leave the ship in a spacesuit and tighten the nut with a normal wrench? (I)
7. How close to the different planets could you get and still remain weightless? (U)
8. What would be the weights of different objects around you if these objects were sent to the various planets and other solar bodies? (I)
9. Can you measure how far an object falls in one second? (I)
10.Can you measure how long it takes an object to fall different distances from a tall building? How does the time seem to be related to the distance an object falls? (U)
11.Is there any such thing as a micrometeorite? Can you find one? (U)
12.Can you measure the speed sound travels? (U)
13.How does temperature affect the speed of sound? (U)
14.Can you take a picture of the moon through a pinhole camera? (I)
15.What is Kepler’s Law? Can you draw to scale the orbit of various planets and the time it takes each planet to reach particular spots in the orbit? (U)
16.From your drawings can you predict when the Earth will be closest to each of the other planets in the Solar System? (U)
17.How does the amount of humidity in the air affect the rate at which a person will sunburn? You might focus the sun’s rays a certain distance from a piece of paper and see how long it takes before the paper is set on fire. Does this depend on the humidity?30 (I)
18.Does land cool off more rapidly than water? How would this affect the climate for cities on the coast and inland? Can you compare the winter temperatures for Portland, Oregon, and Minneapolis, Minnesota? (I)
19.How do the temperatures vary around the world? Get a pen pal in the Southern Hemisphere who is about the same distance from the equator. Compare temperatures and other weather conditions.31 (I)
20.What planets experience winter and summer? Are there any planets that have more than four seasons? (U)
21.What are some ways we could communicate to one another if we were on the different members of the Solar System? (I)
22.What causes a sonic “boom?” Can you experiment with such “booms?” Try snapping a towel or cracking a whip. What causes the pop? (I)
23.As an object increases its speed when moving through a fluid such as water or air, it encounters a greater resistance or drag. If a measured amount of air (say in a balloon) blows against an object, the force it takes to hold the object from moving is the drag on the object. Can you devise a way to measure the drag on differently shaped objects? (U)
24.What effect does the weight of the object have on the drag? (U)
25.What effect does the surface of an object have on the drag? (U)
26.What is the effect of different shaped nose cones? (U)
27.Will a liquid evaporate faster in a vacuum? (I)
28.If you observe and measure the angle to a star at the same time as a friend does who is several miles away, can you figure the distance you and your friend are apart? (U)
29.You can make exact constellation slides. Use very fast film.32 Attach your camera to a tripod and aim the camera at the constellation you wish. Focus the camera at infinity and then expose it about fifteen to twenty seconds. After the negative is developed, punch holes with a pin for each star.33 The size of the hole should match the apparent brightness of the star. Use the slide in a constellarium. (I)
30.What is the effect of the shock of “landing” on various animals? How fast can one safely approach Earth? (U)
31.How large should the parachutes be in order to safely lower objects of different weight? (I)
32.Can you plan a “moon” vacation resort? (I)
33.Can you disprove by experimentation Ptolemy’s theory of the universe? (I)
34.Can you measure the distance to the moon? (U)
35.Can you weigh the Earth? You might want to try the method used by the German scientist, von Jolly, in 1881. (U)
36.How long would it take a Foucault pendulum to make one complete turn at the equator? (See “Foucault Pendulum”.) (I)
37.How is a gyrocompass used in navigation? Can you build a gyrocompass? (U)
1. How often do full moons occur? (Keep a chart of your observations from month to month.) (P)
2. Does the moon always travel the same path through the sky? Use an astrolabe to take readings as to elevation (how high up in the sky) and declination (how many degrees from true north). (I)
3. Does the size of the moon change? (Use a moon stick and “measure” the size of the moon at various heights. See “Moon Range Finder”.) (P)
4. Does the size of the moon change from season to season? (I)
5. What are the dark spots on the moon? (Use a telescope.) (P)
6. Are there mountains on the moon? (Use a telescope.) (P)
7. What causes an eclipse of the moon? (Experiment with models of the sun, Earth, and moon to see how the light given off by the moon can be shut off.) (I)
8. What causes the phases or different shapes of the moon? (Darken a room and then use a projector and a large rubber ball or basketball.) (P)
9. What effect does the shape of the moon have on tides? (Keep a record of the phases of the moon and compare with tide charts.) (I)
10.Will plants grow by moonlight? (Try bean plants.) (U)
11.What kind of light is given off by the moon? (Use a diffraction grating spectroscope.) (U)
12.What is the intensity of moonlight? (Use a light meter or radiometer.) (U)
13.Can you use photographic paper to measure the intensity of the light of the moon? (U)
14.What animals are more active at night? Does this activity depend on moonlight? (I)
15.Can you make a map of the moon through your observations? (telescope) (U)
16.What causes a harvest moon? (I)
17.What causes a hunter’s moon? (I)
18.What would be the weight of various objects in your room if these objects were up on the moon? (I)
19.What is the difference between weight and mass? Would your weight change if measured on the moon? Would your mass change? (U)
20.Has the moon ever been to the same spot in the universe more than once? (U)
21.Could plants grow in soil found on the moon? (I)
22.Can you determine the size of various physical features on the moon? (U)
23.Does the moon revolve? (Note the positions of various features on the moon.) (U)
24.What would happen to the orbit of the moon if the moon should speed up in its path around the Earth? (Whirl a ball on a rubber band.) (I)
25.Can you tell time by the moon? (U)
26.Is the moon always the same distance from the Earth? Can you determine this experimentally? (U)
27.What is the average number of craters per surface area on the moon? Determine this with a telescope. Can you determine the depth by the shadows? (U)
28.What is the best time of the month to study the appearance of the moon? (I)
29.What effect does the shape of the moon have upon success in fishing? (I)
30.Can you make a material with about the same density as the moon? Will this material float in water? (U)
31.Do people all over the world see the same moon as we do? (I)
32.How was the moon formed? (theories of the moon’s origin) (U)
33.Does a full moon affect your ability to think and reason? (I)
34.Are there more babies born during a full moon? (Check hospital records.34) (U)
35.Does the moon always seem to rise from the same place? Does this position vary with the season? (P)
36.How good a mirror is the moon? What part of light does it reflect? (Measure the light from the sun and then from the moon.) (U)
37.How does the surface of the moon compare with that of the Earth? (P)
38.How long would various insects, plants, and animals continue to live if exposed to an atmosphere similar to that of the moon? (I)
39.What plants and animals could live in the temperature extremes of the moon? (U)
40.Are there different kinds of tides? What causes these? Compare a tide chart with a calendar showing phases of the moon. Be sure to figure in the position of the sun at the times shown on the tide chart. (I)
41.Does the moon always look the same? (observations) (P)
42.What happens to the moon the nights we don’t see it? (P)
43.Is the moon larger than the sun? Why does it appear larger? (P)
44.Can you see the stars as well during a full moon as when there is no moon? (P)
45.What are some early legends about the moon? (P)
46.What do we know about the make-up of the moon? (I)
47.Why is the moon yellow? (P)
48.What are the problems in taking a trip to the moon? (I)
49.Could you eat on the moon? (I)
50.What kind of weather is there on the moon? (I)
51.Could man live on the moon? (I)
52.What makes the moon move across the sky? (P)
53.Is there only one moon in our Solar System? (P)
54.If you approached the moon, would the light be brighter? (I)
55.Could bacteria live under conditions similar to those found on the moon? (U)
56.Could we mine different minerals from the moon? (U)
57.Could you plan a summer resort on the moon? What are the problems? (U)
58.Are there volcanoes on the moon? Any moonquakes? (I)
59.What is the man-in-the-moon? Has man ever reached the moon? (I)
60.What experiments could scientists do on the moon? (U)
61.How could you talk on the moon? (Can you experiment with talking through solids, radio in a vacuum, etc.?) (I)
62.What kind of telescope did Galileo use to first view the moon? Can you make one of the same power? (I)
63.How can we find out what the back side of the moon looks like? (I)
64.How can you measure the height of the mountains on the moon? (U)
65.Is the moon gradually moving toward or away from the Earth? (U)
66.Are all the craters on the moon alike? (I)
67.Why do the craters on the moon seem to run in a straight line? (What is your theory?) (U)
68.What is the difference between the volcano and the meteor theory as to the cause of the craters on the moon? What is the bubble theory? (U)
69.What causes the “seas” on the moon? Can you measure some of these “seas?” (U)
70.Why are the mountains on the moon taller and more jagged than those on Earth? (Try some experiments with erosion and weathering.) (I)
71.Can you locate domes on the moon? (U)
72.Can you find rays on the moon? (Use binoculars or a telescope. Look for white craters.) ( U)
73.Can you find clefts or deep cracks in the moon? (U)
74.Would the temperature change very much inside the caves on the moon? (Experiment with caves found on the earth.) (U)
75.Can lichens live on the moon? Experiment by growing lichens under different conditions. (I)
76.Could we get oxygen from the rocks on the moon? Can you get oxygen from rocks found on Earth? (U)
77.Would you see more stars from the moon than from the Earth? (I)
78.How would the Earth appear from the moon? (I)
79.Is the moon round? What causes its strange shape? (I)
80.What causes the strange moving shadows on the moon? (U)
81.What causes a “mist” in the crater Plato? (U)
82.Can weather predictions be made accurately from the appearance of the moon? (I)
Heat, Light, and Color
1. Is heat matter? Weigh different objects. Then heat the objects. Do the objects gain weight? (P)
2. Can you disprove the theory that heat is a fluid that flows in and out of objects? (I)
3. Is heat produced when you bore a hole with a drill? What effect does the sharpness of the drill have on the amount of heat produced? Can you measure this heat with a thermometer? (I)
4. What objects become hot when rubbed together? Can you rub various objects and measure the amount of heat given off? Try rubbing a coin on a piece of wood. (P)
5. Is heat kinetic or potential energy? Put a few eyedroppers of ink35 in cold water. Try the same experiment with hot water. What do you observe? (I)
6. Can you determine the amount of energy in different liquids at various temperatures? (U)
7. Can you determine the amount of energy possessed by different gases at various temperatures? (U)
8. What is the effect of heat energy on the movement of molecules? Heat water containing a few drops of food coloring. (P)
9. Can you detect the movement of molecules? Observe the Brownian movement through a microscope. (U)
10.Is the Brownian movement the same in all liquids and gases? (U)
11.What effect does added heat energy have upon the Brownian movement? (U)
12.Is temperature the same as heat? Place a pan of boiling water in the refrigerator. Place alongside the water a pan of sand heated to the same temperature. Place in the same refrigerator a kettle of lukewarm water. Which one reaches 45 °F first? (I)
13.What factors affect the heat content of an object? What effect does temperature, mass, and kind of substance have on the heat content? (U)
14.Can heat exist as potential energy? (U)
15.Does the temperature of ice change while the ice is melting? (P)
16.How hot can water become in the liquid state? Can water become hotter as vapor? (I)
17.Do all solids melt at the same temperature? Try ice, butter, grease, various crystals, and other solids. (P)
18.How accurate are your senses in determining temperature? Place a finger of one hand in ice water. Place your other hand in hot water. Then place both fingers in lukewarm water. (P)
19.What parts of your body are the most sensitive to changes in temperature? (I)
20.Are girls or boys better detectors of temperature? Try some experiments to see which students are best at detecting changes of temperature. (U)
21.How do various forms of matter change when heat is given off or absorbed? Can you detect and measure these changes? (I)
22.How did Galileo make the first thermometer? Can you make one using the same principle? How accurate is this type of thermometer? (I)
23.Can you make a thermometer using a glass tube and water? How accurate is your thermometer? (U)
24.Can you determine the freezing point of water? Is it the same as the melting point of ice? (P)
25.Does salt water freeze at the same temperature as fresh water? What effect does the amount of salt have on the temperature at which the liquid freezes? (I)
26.Can you determine the freezing point of various liquids? (U)
27.Can you determine the boiling point of water? (I)
28.What effect does adding salt to water have on the temperature at which the salt water boils? (I)
29.How was the Fahrenheit thermometer developed? Can you make a thermometer and scale using Fahrenheit’s methods? Why is the freezing point of water 32° on a Fahrenheit scale? (U)
30.Can you make a mercury thermometer?36 What is the freezing and boiling point of mercury? How can you determine and measure this? (U)
31.How can you change (convert) the readings of a Fahrenheit scale to those of a Celsius scale? Can you make a thermometer of each type and make the conversion by an experimental method? (U)
32.What are the advantages and disadvantages of mercury and alcohol thermometers? (I)
33.How does a clinical thermometer work? Is the mouth temperature of all animals the same? (I)
34.What is the difference in temperature between mouth and rectal temperature of various animals? (U)
35.How are thermometers calibrated by using hydrogen and helium gas? Can you devise a means to do this? (U)
36.Can you determine experimentally the accuracy of various thermometers sold in stores? (I)
37.Can you set up an experiment to change mechanical energy into heat energy? Can you measure the amount of mechanical energy necessary to produce a certain amount of heat energy? (I)
38.Does all matter expand when heated? (I)
39.Can you detect and measure the expansion of different metals? (I)
40.In which directions do different kinds of matter expand? Is this expansion uniform in all directions? (U)
41.What effect does temperature have on the expansion of different metals? (P)
42.Can you determine the coefficient of linear expansion of various metals? (U)
43.Can you determine the distance certain metals should be separated at various temperatures in order to allow for expansion? Why is the maximum and minimum temperature of an area important in laying metal lengths such as railroad rails? (U)
44.Can you identify metals by determining their coefficient of linear expansion? (U)
45.What is the total seasonal change in the length of steel cables used to support bridges in your area? Can you determine this? (U)
46.Can you determine the expansion rate of various non-metals such as glass, ice, cement, plastic, etc.? (I)
47.What effect does heat have on a bimetallic bar? Can you make a bimetallic bar by riveting strips of two different metals together? (I)
48.What effect does cooling have on different bimetallic bars? (I)
49.How does a thermostat work? Can you make a bimetallic bar by using aluminum foil and paper fastened together for the two strips? (P)
50.Can you make an operating thermostat? How accurate is it compared to a regular thermostat? (I)
51.Can you devise a thermostat to control the temperature inside an incubator so you can hatch eggs? (U)
52.How does expansion of metals affect the accuracy of a pendulum clock? How can you compensate for this expansion? (U)
53.What effect does temperature change have on the expansion of water? Place a thermometer (preferably Celsius) in a bottle of water. Insert a long piece of glass tubing in a one-hole stopper. Have the glass tubing stick up about two feet above the top of the jar. Push the stopper into the bottle until the water is forced quite high up the glass tube. Place the jar in packed ice. Note the height of the water in the tubing and compare this with the temperature reading. Keep a graph if you can. (U)
54.Does salt water cooled below 32 °F expand or contract as the temperature decreases?37 (U)
55.Why does ice float on the top of the water? (P)
56.What is the temperature of water at different depths in ponds and lakes? (I)
57.What effect does the temperature of air have on the temperature of the water at different depths? (U)
58.What is the temperature of salt water (ocean or bay) at different depths? Does this vary with the season of the year? (I)
59.Why does a pond freeze over only on top and not on the bottom? (I)
60.What effect does the freezing over of a pond have on the life underneath the surface of the ice? (U)
61.What is the effect on different gases if the volume is the same but the temperature changes? Can you use the size of a balloon as a measure of gas pressure? Now vary the temperature by using a refrigerator, outside temperatures, and heating. (I)
62.Can you determine the pressure coefficient of different gases? (U)
63.Can you devise and convert the different temperature scales to a standard scale? You must find out about Celsius, absolute or Kelvin, and perhaps other scales. (U)
64.What is the relation between the absolute (Kelvin) temperature and the pressure of a gas? Try changing temperatures and recording the pressure. Change your findings to the absolute scale. (I)
65.What is the relationship between the volume of a gas and its temperature? If you hold the pressure the same (by using a standard weight to push on the gas in a container), what happens to the volume as you increase the temperature? Keep a graph of the change and the temperature. (U)
66.Why might the surfaces of large rocks chip during hot summer days? (I)
67.Why are concrete sidewalks made with spaces between the sections? (P)
68.What materials would be better than steel to use for surveyors’ tapes? (U)
69.Why do fountain pens which are nearly empty tend to leak while being used? (U)
70.Why is a thick glass less likely to crack than a thin glass when hot water is poured into it? (P)
71.Can Pyrex glass stand the shock of a sudden temperature change? Why? (I)
72.Why does bread dough rise? What effect does the amount of kneading have on the volume of bread dough expansion? Check for carbon dioxide. (P)
73.Will balloons rise if filled with hot air? Why? (P)
74.Why should the moving engine parts be made of the same material? (I)
75.What effect does the size of the bulb and the diameter of the tube have on the amount of liquid that rises inside a thermometer? How can you make a thermometer more accurate? Experiment with glass tubing inserted in a bottle of water and sealed with a rubber stopper. (P)
76.Why should wires sealed in glass have the same coefficient of expansion as the glass?38 (I)
77.Why does the level of liquid in a thermometer suddenly dip when the bulb is placed in cold water? (I)
78.Can you use a hydrometer and a thermometer to determine the temperature at which water has its greatest density? (U)
79.Can you determine experimentally the heat lost or gained by water? What effect does changing the amount of water (mass) have on the heat loss or gain at a given temperature change? (I)
80.Can you experiment with mixing varying amounts of water at different temperatures? What is the resultant temperature of the mixture? An example might be mixing 50 cc of water at 20 °C with 30 cc of water at 40 °C. Can you predict the resulting temperature? (I)
81.Can you determine the specific heat of various metals, air, steam, ice, and water? (U)
82.Does metal gain and lose heat at the same rate as water? Measure the temperature of a piece of metal. Measure the temperature of very hot water, and drop the metal into an equal volume of water. Remove the metal and record the temperature of the metal and the water. (I)
83.Does it take more heat, weight for weight, to heat water or earth? Place samples of each in containers. Heat for the same period of time and take the temperatures. (P)
84.Why does a shallow lake warm up quicker in the spring than a deep lake? (I)
85.What effect does a large body of water in the area have on the growing season? (I)
86.If water contains ice, does the water start to heat immediately when heat is applied? What happens to the heat energy? (P)
87.Can you determine the heat of fusion (extra heat required to change a substance from a solid to a liquid) of ice and other solids? Mix equal amounts of ice (0 °C) and hot water (90 °C). The temperature should be 45 °C. The actual temperature is much less. The difference changed to calories is the heat of fusion. (I)
88.Can you determine the fusing point (temperature at which substance turns from a solid to a liquid) of different solids such as ice, frozen salt water, beeswax, mercury,39 butter, and tin? (I)
89.Why is ice a good refrigerant? (P)
90.Does wrapping ice in paper or burlap help or prevent refrigeration? (I)
91.What is the temperature of dry ice? What is the heat of fusion of dry ice?40 (P)
92.What does dry ice consist of? Test the gas given off with a burning match. Test the gas with lime water. (P)
93.What effect on the melting rate of ice does the exertion of pressure on the ice have? Attach two weights to a wire. Hang the weights over the block of ice so the wire presses against the ice. Try different weights and kinds of wire. (I)
94.Why does a snowball pack? Why does some snow pack easier than other snow? (I)
95.If you stand on ice, why do the skates freeze to the ice? (U)
96.Do liquids evaporate more rapidly when hot or cold? Can you keep a chart on the rate of evaporation of different liquids and varying temperatures? (P)
97.Do wet clothes dry more quickly on a calm or windy day? (P)
98.Do liquids evaporate more quickly in open pans or pans with a small opening? (I)
99.Do all liquids evaporate at the same rate? (P)
100. Does evaporation cause cooling? What is the effect of the rate of evaporation on the temperature of the object? Place alcohol and water on your wrist. (P)
101. Why doesn’t a liquid evaporate in a closed container? (U)
102. How does a vacuum affect the normal rate of evaporation of a liquid? (U)
103. Can you determine the rate of sublimation (solid changing directly to a gas) of various substances such as ice, moth crystals, dry ice, and sulfur?41 (I)
104. What happens when water boils? What are the first bubbles that rise? Do the bubbles get larger or smaller as they rise in the liquid? Why do bubbles form? (I)
105. Can you determine the heat of vaporization (the quantity of heat per gram required to vaporize the liquid without changing its temperature) of various liquids? (U)
106. What is the heat of condensation and how can you measure it? How does this affect weather conditions, particularly hurricanes? (U)
107. What effect does the pressure on a liquid have on the temperature at which the water will boil? Boil water in a flask. Remove from the heat and insert a stopper. Turn the flask over and run cold water on the bottom.42 (I)
1. Are all lenses the same shape? (Collect lenses from eyeglasses, old cameras, viewfinders, flashlights, etc.) (P)
2. How do objects look through different kinds of lenses? (P)
3. What are lenses made out of? (I)
4. Can a drop of water serve as a lens? Place a drop of water on some Saran Wrap that is covering a page from a newspaper. (I)
5. What has the size of the drop to do with the amount of magnification? (I)
6. Can you determine the focal length of the various lenses? How far do you hold a lens above a piece of paper in order to focus the light to one point? (P)
7. What is the temperature of various lights focused to a point? Try sunlight, artificial light, candle, and match. (I)
8. How far from the lens does the image form? How far away do you hold the lens from your eye in order to focus on a distant object? (I)
9. Is this distance the same as the focal point or greater? (I)
10.How does the image distance (distance from the lens to where the image is in focus) change as the object distance (distance from the object to the lens) changes? Does this formula help solve the problem: l/Do+1/Di= 1/F? (U)
11.Can you build a smoke box to study the rays of light entering a lens? Cut out part of a cardboard box and cover the hole with Saran Wrap. Burn incense for your smoke. Mount your lens in a hole at one end of the box. Use a small pencil flashlight43 for a source of light. (I)
12.Can you use other liquids besides water as a lens? (U)
13.Does a clear marble work as a lens? (P)
14.Does a lens have more than one focal point? Try both sides of the lens. (U)
15.How does the diameter of the lens affect the amount of light admitted? (U)
16.Try using lenses in combinations. How does this affect the focal point, image, and object distance? (I)
17.Why are some objects upside down when seen through a lens? How can you make the objects right side up? (U)
18.Can you measure the power of different lenses? Make a series of parallel lines about 1/16 inch apart. Focus the lens on these lines. If you see three lines outside the lens for everyone line seen through the lens, the lens would be rated three power. (I)
19.Can you use a mirror to reflect light through a lens? Do you get more or less light this way? (U)
20.Can you use a concave shaving or vanity mirror to focus light to a point? Hold a pencil in front of the mirror. Move the end of the pencil slowly away from the shaving mirror. The point where the image turns upside down is near the focal point. Use the mirror to focus light or rays on a sheet of paper. Measure the distance from the lens to the point. (P)
21.Do concave mirrors act the same as concave lenses? Try experiments mentioned above. (I)
22.Can bottles be used for lenses? Are bottles thrown from cars a forest fire hazard? (I)
23.Can you measure the amount light bends in different liquids and solids? (This bending is the refractive index.) (U)
24.Can you focus moonlight? How does the temperature from moonlight compare with temperature from sunlight when focused through a lens? (I)
25.Can you make a sample reflecting type of telescope by using a shaving or vanity mirror, plain mirror, and a small concave lens? Find out how a reflecting telescope works. (U)
26.What is the difference between a refracting and a reflecting telescope. (I)
27.How are lenses made? Can you make a lens? (U)
1. What is black light? How was it first “discovered?” (I)
2. What rocks and minerals fluoresce when exposed to black light in a darkened room? (P)
3. What rocks and minerals retain this fluorescence after the light is removed? (P)
4. Can you determine the color certain minerals in rocks will fluoresce under black light? (I)
5. What effect does the length of time a material is exposed to black light have on the length of time it will retain this ability to fluoresce after the light has been removed? (I)
6. What effect does black light have on plant growth? (I)
7. Why will certain articles of clothing fluoresce under black light? Try a T-shirt. (I)
8. What soap powders fluoresce? What is the “magic blue whitener?” (U)
9. Can you paint a picture with fluorescent or phosphorescent paint? Try novelty stores or hardware stores for the paint. This is an excellent project to use around Halloween. (P)
10.Can you detect the difference between fresh and old eggs with black light? How old do the eggs have to be before their age can be detected? (I)
11.What kind of uses can you devise for black light in crime detection? Can you test your theories? (I)
12.How do laundries use black light for identifying clothing? (I)
13.Can you use black light to trace the growth of plants and certain animals? (U)
14.Can you devise a way of measuring the wave length of different black lights? (U)
15.Can a person get a “suntan” from black light? (P)
16.Can you experiment with black light on the movement of different animals? (P)
17.What effect do color filters have on black light? (I)
18.Do plants exhibit a negative or positive tropism (attraction) to black light? (P)
19.Are plants more attracted to black light or natural light? (I)
20.What effect does black light have on a radiometer? (I)
21.What spectrum is cast by black light? Use your spectroscope. (I)
22.Can you focus black light rays with a lens? What is the temperature of such focused rays? (U)
23.Can you use black light to operate a photoelectric bulb? (U)
24.What is the effect of black light on the growth of bacteria, mold, and protozoa? (U)
25.Can black light be used to kill germs? (I)
26.Does black light travel in a straight line? (P)
27.What causes certain minerals to fluoresce? Can you change this property in these materials? (U)
28.Can you experiment with different foods such as nuts, butter, meats, and vegetables to determine the effect black light has on them and also to determine if this effect changes with the age of the food? (I)
1 See Note 22 in Appendix E about getting a star chart like this. Download-and-print is a good method!
2 E.g., a document camera plus digital projector.
3 Notations vary by star chart.
4 See Note 23 in Appendix E if yours does not have an up-to-date planet chart.
5 This was the case at the time that the original book was written but is not true in general. We can expect Jupiter and Saturn to be close to each other again in the years 2020 and 2040.
6 See Note 24 in Appendix E for some sources of lenses.
7 Rather than starting with paper and paper tubes, can you design a version of this that could be 3D printed?
8 The one with the shorter focal length.
9 See Note 25 in Appendix E about gratings.
10 Also interesting to look at: a white LED, colored LEDs, light from a laser pointer, and different types of streetlights.
11 The 2” × 2” size is that of a traditional photographic slide, and the hole is to make a small beam of light with a traditional slide projector. How can you make a similar narrow beam of light with a modern computer projector?
12 Native Americans.
13 While “planetarium” is correct in this context, the term “Orrery” is more common.
14 Steel music wire may be used as a substitute for the coat hangers. You can find a used phonograph (record player) at a thrift store or substitute a hardware store lazy susan, rotated by hand.
15 This is actually not quite good enough for the job. See “Modern Safety Practice”.
16 A bell jar is a glass vessel designed to hold a vacuum.
17 Using mercury—and building this project as described—is not advised. Please read Note 26 in Appendix E for alternatives and discussion.
18 Rather, visit weather.gov and look up the current barometer reading for your zip code!
19 Preferably, an old bicycle pump that you don’t mind destroying
20 Your tire pump may have a different type of valve mechanism. If so, can you figure out how to reverse it?
21 Important: Read Note 1 in Appendix E about working with animals.
22 Some people suggest using a solid Nalgene container as a bell jar. The same safety precautions should be used with plastic as with glass.
23 See Vacuum Grease in Appendix A.
24 An old satellite dish may also be used like an umbrella.
25 or toothpicks
26 Could you design a version of this that uses LEDs (Light-Emitting Diodes) instead?
27 The moon range finder (“Moon Range Finder”) comes to mind!
28 See Note 27 in Appendix E for telescope suggestions.
29 Really, you want a long exposure, not time lapse. What is the difference?
30 Related question: What is sunburn, and how does it relate to paper burning?
31 Modern interpretation: Check worldwide weather at worldweather.org or forecast.io, and compare weather conditions at similar lattitudes to your own, both north and south .
32 That is, a high ISO number on your digital camera!
33 With a digital camera, print your image and use it the same way.
34 You may be able to look up Vital records statistics online.
35 Food coloring.
36 Working with mercury is not recommended, due to its toxicity. Here is a real challenge: Can you make a mercury-free liquid-metal thermometer?
37 Is this the same as supercooled water? If not, how is it different?
38 What is Kovar?
39 Is it safe to use a sealed mercury switch to do this experiment?
40 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 further discussion.
41 See Note 20 in Appendix E about mothballs and Note 14 in Appendix E about dry ice.
42 Glass can shatter during rapid temperature changes; take appropriate precautions.
43 Or a laser pointer.