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Experiments
provided by Dr Audrey Matthews, Department of Applied Science, De
Montfort University
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| The
humble film canister |
1.
What you need
Denture cleaning tablet, film canister, blue tack or plasticine,
water, towel, lemon juice, paper.
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| Follow
Dr Audrey Matthew's simple instructions |
2.
What to do
Break
the denture cleaning tablet in half and stick to the underside of
the lid of the film canister with blue tack. Half fill the film
canister with water. Put the lid on the canister and turn upside
down onto a towel positioned on the floor. CAUTION - stand well
clear and wait for the pop!
Also use the lemon juice and cocktail stick to write a secret message
on a piece of paper. Reveal the secret message by warming the paper
over a radiator.
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| How
do you make a balloon inflate without blowing? |
3.
What’s happening?
Many chemical reactions take place in our houses. Denture cleaning
tablets are largely made up of sodium bicarbonate, which reacts
with water to form a gas called carbon dioxide. This expands and
causes pressure to build up in the canister. After a few moments
the lid is forced apart by the pressure to create a small rocket.
Lemon juice reacts to form a dark compound when it is heated. This
allows us to see the secret message.
Want
to investigate some more?
Try adding denture tablets or baking powder to half-filled plastic
bottles with balloons over the neck. How many tablets or spoons
of baking powder are needed to inflate the balloon fully? (You might
want to blow up the balloon first to stretch the rubber.)
Look in the kitchen at other things that might involve chemical
reactions. The making of bread, cakes and sweets like honeycomb,
are a few examples.
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