28 August 2002 1637 BST The
burp in a pot experiment
James gets ready to hear some rude noises
Welcome to the burp in a pot experiment! This is
one you can try at home, and it has a dramatic result.
Get an adult to help you. Be safe and stay well back when you've
set it up.
You will need:
Half a soluble tablet
An empty film canister
Water
First put a small amount
of water in the film canister (just enough to cover the bottom).
Then drop in the half-tablet.
Quickly
put the lid on the canister and turn it upside down so it
rests on the lid. Then stand back!!
It’s best to do this outdoors, or at least
not near anything breakable. It might take a while but don't
go back to it once you have set it up - stay well back! What
do you think will happen?
The flying canister moves so fast, it is just
a blur in the picture below. Check out the video to see it for
real. Try doing a whole lot of them together and seeing which
ones go first.
Why does this happen?
Water-soluble indigestion tablets are made up of
powdered acid and base bound together.
The grey blurry mark is the film canister shooting into the
air. James makes sure he stays well back
When dry they don’t react, but when dissolved in
water the acid reacts violently with the base to make carbon dioxide
gas – this is what makes it fizz.
When this happens inside a film canister the gas
can’t escape like it does in a glass, so the pressure builds up
until it is enough to blow the canister violently up into the air.