20 Minute Labs: Elephant Toothpaste

MAKE TOOTHPASTE FIT FOR AN ELEPHANT!

Have you ever seen an elephant at the zoo or in the movies? Did you notice those big tusks? Those are actually two very large teeth.

Imagine if elephants had to brush those teeth? They'd need a very large tube of toothpaste!

In this month's 20 Minute Lab, we'll be using some household items to produce an exothermic chemical reaction. The result is a fun oozing foam - big enough to use as elephant's toothpaste!

The main ingredient for this experiment is hydrogen peroxide - a common first aid supply. The hydrogen peroxide in your cabinet is probably a 3% solution, which will work just fine for the experiment. If you want a more powerful reaction, you can use 12% hydrogen peroxide, which you can find at beauty supply stores, but make sure you ask an adult to handle it. The adult should wear gloves, since 12% hydrogen peroxide can irritate the skin.

WHAT YOU’LL NEED

• tray, plastic tub, or washable mat (You can use the one from your Foundation Chemistry kit if you have one!)
  
• bottle with narrow neck
• measuring cup
• measuring spoons
• hydrogen peroxide (standard 3% works, but 12% works even better)
• food coloring (optional, but fun!)
• dish soap
• package of dry yeast (we used the measuring spoons, as we had bulk yeast)
• water

LET'S GET STARTED

1. First, if you want to make it really seem like an elephant's toothpaste, you can cut a piece of paper to fit around your bottle and decorate it with markers or crayons to make it look like a toothpaste bottle! This isn't required for the experiment though, it's just for fun.
2. Place your bottle on the mat or whatever you're using to catch the excess foam.
3. Pour 1/2 cup of hydrogen peroxide into the bottle. (If you're using 12% hydrogen peroxide, have an adult do the pouring with gloves on, and perhaps using a funnel.)
4. Add 8 drops of your favorite color food coloring.
5. Add a good squirt of dish soap. Swirl to mix.
6. Rinse out your measuring cup. Add 1 tablespoon of yeast and 3 tablespoons of warm water. Stir gently for about 15 seconds.
7. Pour the yeast mixture into the bottle.
8. Observe what happens!

The red toothpaste was made using the standard 3% hydrogen peroxide.

The blue toothpaste was made using 12% hydrogen peroxide! If you decide to use 12%, make sure to have an adult help and use gloves! (Note: We propped up the bottle a bit so the "toothpaste" squirted out to one side!)

CONCLUSION

What's going on?

Did you make an oozing foam? Why did this happen?

The chemical formula for hydrogen peroxide is H₂O₂. This means it is made up of two hydrogen atoms and two oxygen atoms. Can you see how similar hydrogen peroxide, H₂O_2, is to water, H₂O?

If you left a bottle of hydrogen peroxide open to the air, over time it would slowly break down into water (H₂O) and oxygen (O₂). The oxygen would be released as tiny bubbles of gas that would dissolve into the air.  Eventually you would just be left with a bottle of water - but this would take a long time!

Adding yeast dramatically speeds up this process. This is because a package of yeast contains "catalase". Catalase is an enzyme that speeds up the breakdown of hydrogen peroxide into water and oxygen.

Note: When something speeds up a reaction it's called a catalyst. There are lots of different types of catalysts, but this one's easy to remember: catalase the catalyst!

In our experiment, the dish soap traps the oxygen gas (O₂), which creates lots and lots of bubbles! All this bubbling makes the substance quickly expand and shoot out of the bottle.

You might notice that your bottle is now a bit warm! That's because this chemical reaction produces heat. This type of reaction is called an exothermic reaction ('exo' means outside or external and 'therm' means heat).

At this point what's left in your bottle in just soap, water and oxygen, so you can pour the remains of your experiment safely down the sink!

Let us know what you did. Share your photos and results with us on Facebook, Twitter, Instagram, or send us an email to info@yellow-scope.com. We love getting your messages!

For more exciting experiments, check out our Yellow Scope Science Kits on the Shop tab of our website!