week 19: elephant's toothpaste

This has gotten quite popular recently! Make sure you have ample space if you decide to try this one out for yourself. Adult supervision may be required.

Materials: 

• 1/2 cup hydrogen peroxide (6% solution, 3% may be easier to find at your local drugstore but the reaction will be a little toned down)
• Plastic water bottle
• Yeast (one packet)
• Warm water
• Food coloring
• 1/4 cup liquid dish soap
• Funnel
• Cup/bowl

Directions:

1. Pour the hydrogen peroxide and dish soap into the water bottle using the funnel. Add about 5 drops of food coloring as well.
2. Remove the funnel and gently swirl around the bottle's contents.
3. In the cup or bowl, mix the packet of yeast with some water and mix until it is foamy. Leave it to sit for about 5 minutes.
4. Place the funnel back on the bottle and pour the yeast mixture in!

What's Going On?
The hydrogen peroxide (H₂O₂) has oxygen in it, as seen by the O₂ in its formula. Adding the yeast to the hydrogen peroxide took out this oxygen very quickly -- it was a catalyst, meaning it sped up the reaction. This made a lot of bubbles, as you saw.