MAKING OXYGEN - Things That Catch Fire or Go Bang - Why Is Milk White?: & 200 Other Curious Chemistry Questions (2013)

Why Is Milk White?: & 200 Other Curious Chemistry Questions (2013)

5. Things That Catch Fire or Go Bang




Protective goggles

1 packet active dry yeast (available at grocery stores)

2-liter soda bottle, empty and clean

Hydrogen peroxide, 3 percent solution (available at drugstores and pharmacies)



Bamboo skewer (optional)

Matches (optional)


You probably have everything you need to fill a balloon with pure oxygen. All it takes is some hydrogen peroxide from the medicine cabinet and some yeast from the kitchen.

All oxygen-breathing creatures make hydrogen peroxide as an inevitable byproduct of respiration. Since it can damage the cell if it is not destroyed, most cells have an enzyme called catalase that breaks hydrogen peroxide down into water and oxygen. That is why hydrogen peroxide bubbles when you put it on a cut or scrape. Your own body has produced catalase, and that is breaking up the peroxide.

Yeast cells also breathe air and use the oxygen to burn sugar to get their energy. So they also produce hydrogen peroxide that they need to get rid of by using the catalase enzyme. So if you put some yeast in a bottle and pour in some hydrogen peroxide, you get bubbles of oxygen. The reaction is exothermic, meaning it generates heat, and you can feel the bottle get warm in your hand as the reaction takes place.

Pour the contents of a packet of active dry yeast into an empty two-liter soda bottle. Pour up to a couple inches of the hydrogen peroxide into the bottle. Three percent hydrogen peroxide, the kind you use for first aid, works fine. Be sure not to fill the bottle too high.


Place a balloon over the top of the bottle and watch it inflate as it fills with oxygen. The reason you had to be careful not to fill the bottle too high was so the bubbles won’t flow over of the top and into the balloon. You may still have to shake or tap the bottle to prevent the bubbles from rising too high.

Once you have a balloon full of oxygen, you can start to have fun. For safety reasons, always wear protective goggles for this next part of the experiment.

First, see what happens when you blow up a balloon the normal way, using air from your lungs, and then aim it at a lit candle. Just like what happens on a birthday cake, the candle simply goes out. Now see what happens when you try to blow the candle out using the balloon full of pure oxygen.


See the video at

The candle doesn’t go out. Instead, it gets brighter. Look at how the camera adjusted to the extra brightness by making the rest of the picture dimmer.

You can use the same technique to make oxygen in a water glass, and then try to pop a bubble of oxygen with a hot coal on the end of a stick. (You can create one easily by lighting a bamboo skewer on fire then blowing it out, turning the end into a glowing-red coal.) When the bubble pops, a small explosion happens as the oxygen causes the hot coal to burst into flames. Of course, you’ll need protective goggles for this experiment as well.


See the video at