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Elephant’s Toothpaste

  • Empty plastic bottle

  • Dry yeast (found in the baking section of the grocery store)

  • Warm water

  • Liquid dish soap

• Measure 1/2 cup of hydrogen peroxide, and carefully pour it into
the bottle.
• Add a big squirt of dish soap into the bottle, and swirl gently to mix.
• If you want to make your foam a single colour, add a few drops of
food colouring directly into the hydrogen peroxide, and swirl the
bottle gently to mix. If you want to give your foam stripes like some
toothpastes, put the drops along the inside rim of the bottle’s mouth.
Let them drip down the inside of the bottle, but do not mix.
• In a measuring cup mix together one tablespoon of yeast and three
tablespoons of warm water. Stir for about 30 seconds.
• Pour the yeast mixture into the bottle then quickly step back,
and watch your reaction go! What happens? How long does the
reaction last?

  • Extra 1: Try the activity without the dish soap. What happens? How was the result diff erent?

  • Extra 2: Try the activity with diff erent-shaped containers. What happens if you use a bottle with a narrower or wider neck—or a cylindrical drinking glass with no neck?