"Let the words of my mouth, and the meditations of my heart be acceptable in thy sight, O Lord, my Strength, and my Redeemer." Psalm 19:14

Whale Evolution 1

Whale Evolution 2

Sunday, October 05, 2008

Can Crushing - Air Pressure Demo

From Apologia Physical Science text:
The key to doing this one is speed. Put a small amount of water (SMALL amount, just cover the bottom of the can) in an empty soda can. (Or as we say in the deep South, a Coke can which means any soft drink). Have a bowl of ice water ready nearby. CLOSE BY! And wear heat proof gloves. (I've tried using tongs. Unless you are great with tongs and can move fast with tongs, forget the tongs and go with heat proof gloves!). Put the can on a heat source (as you can see in the photo I just used the eye of a stove. When you see steam coming out of the can (proof of boiling water) you know that the air in the can is HOT HOT HOT. And this is what you want.
The air pressure in the can has now risen and it is pushing against the sides of the
can as hard as it can (of course some is coming out of the hole in the top of the can and that is why you want to move quickly.). Cover the hole with your hand (you are wearing heat proof gloves right. This is important unless you want to treat burns later.). MOVE QUICKLY NOW. I cannot emphasize this enough.
Put the can upside down (HOLE DOWN) into the ice water. QUICKLY. The can will
collapse into itself as the air goes from HOT to COLD quickly - it pulls the sides
of the can in with it. (If you were too slow it won't work and you get to try all
over again.).

It is a "do that again" experiment (as you can see!) I did it 3 times this week
with different results each time but it worked all 3 times.

No comments: