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Terry Casey

In article ,
lid says...

My stepfather used to teach me science through, say, explaining why
popcorn popped.

EXPLAIN

A favourite trick was to get an old-fashioned tin with a replacable
lid, like a syrup or treacle tin, and punch one hole with a nail
through each of the base and the lid. You then:
1) Remove the lid
2) Seal the hole in the base of the tin with a finger
3) Turn it upside down
4) Fill it with gas from the cooker (gas is lighter than air, so it
goes up into the tin). Er, turn the gas off once you smell gas! That
means it's full!
5) Replace the lid
6) Seal the hole in the lid with another finger (so you're now
sealing both)
7) Turn it the right way up
8) Run out into the garden and place it on something like a brick
9) Light the gas at the lid hole, and stand well back.
After a few seconds the lid goes about 15 feet in the air.

EXPLAIN

Another was to get an old can, not one that contained anything highly
flammable, something like olive oil would do. Put a centimetre or two
of water in the tin, and boil it until steam is coming out of the top.
Then turn off the gas, and quickly, using oven gloves, replace the lid
making sure it's tight. Stand back and wait. After a while, the can
crumples.

EXPLAIN

Why do flour mills explode?

Connect a funnel to a (longish) length of tubing.
Block the bottom of the funnel with a loose plug of tissue and pour
flour into the funnel.
Place a lighted candle on the top of a wall or similar, a couple of
inches from the edge.
Hold funnel against wall and place 7lb biscuit tin or similar over both
candle and funnel, so that funnel is held in place btween tin and wall.
Blow sharply down tubing.
The tin may travel some considerable distance, so stand well clear!

EXPLAIN

--

Terry