RAISING RAISINS – BAKING SODA INVESTIGATION
1. What
do you think will happen if you put a raisin in a glass of water?
Do you think it’s possible to make raisins
rise to the top and jump around?
WHAT YOU NEED:
• A
pint glass
• Warm
water
• Raisins
or anything else you would like to test.
• Bicarbonate
of Soda (Baking Soda)
• White
Vinegar
INSTRUCTIONS
1. Fill the glass half
full with warm water.
2. Add two heaped teaspoons
of baking soda.
3. Add a few raisins
4. Put the glass in a
tray – it might overflow
5. Top of with white
vinegar
2. WHAT
DO YOU SEE?
3. WHY
DO THE RAISINS DANCE?
The vinegar and bicarbonate of soda react forming carbon dioxide. The carbon
dioxide bubbles collect over the surface of the raisins. As carbon dioxide is lighter than water it rises to the top and takes the raisins with it. As the bubbles pop at the surface the raisins drop again, only to be covered in bubbles again at the bottom
until the reaction finishes.
MORE INVESTIGATION IDEAS
1. Can you find the smallest
amount of baking soda and vinegar that allows the raisins to dance? Try with just one raisin and then investigate to discover if you need more to make 2 raisins dance.
2. Can you think of anything
else this would work with? You could investigate using other dried fruits and record how well each dance.
3. We tried with small
LEGO pieces and found that they sank when they filled with water and once the reaction started,they
jumped to the top, but didn’t dance around.
WHY DO BAKING SODA AND VINEGAR REACT?
If you combine an acid (vinegar) and an alkali (baking soda) they react together
to neutralise each other.
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