YEARS K–6 IDEAS FOR THE CLASSROOM
Just Because it Looks like Water, Doesn’t Mean it Is! (continued)
'Elephant's Toothpaste' with 3% hydrogen peroxide
How to take this experiment up a notch:
- Increase the speed and heat produced by using hydrogen
peroxide 6% instead of 3%. This is found at your local
pharmacy.
- Use water instead of hydrogen peroxide to show the difference
in the reactions (nothing should happen).
- If you’re really keen, replace the hydrogen peroxide 3% with
50-80 mL of 35%/30% hydrogen peroxide, replace the yeast
mixture with 8g potassium iodide (KI) dissolved in water,
replace the pop-top bottle with a 2L glass conical flask and
use 10mL of liquid soap. Stand back quickly after you pour
in the potassium iodide because the foam will shoot up very
quickly and fall back down! Make sure you do this experiment
outdoors and don’t let the students know that you are using
the potassium iodide for their own safety in case they decide
to repeat the experiment at home.
Carbon dioxide is produced when white vinegar and
bicarbonate of soda are mixed
3) Elephant’s Toothpaste
In this experiment, you are comparing water with hydrogen
peroxide.
Materials and Method: 120mL of 3% Hydrogen Peroxide, 1
sachet of dry yeast mixed with 4 tablespoons of warm water, a
squirt of liquid detergent, drops of food colouring (optional), pop-
top bottle, funnel.
1. Pour the hydrogen peroxide into the bottle using a funnel.
2. Squirt a few drops of liquid detergent into the bottle.
3. Squirt the food colouring into the bottle.
4. When you’re ready to show the class the chemical reaction,
pour the yeast mixture into the bottle. With the pop-top lid on,
a thick foam should squirt out the pop-top lid.
'Monster's Toothpaste' with a higher percentage of hydrogen
peroxide
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SCIENCE EDUCATIONAL NEWS VOL 67 NO 1