Wednesday, August 30, 2006

The Return of Density - Episode 13

Some things float in water and others sink, but can the same thing both float and sink? Better yet, Dr. Carlson demonstrates water that sinks in water.

Science Theater Episode 13: Density Changes

2 comments:

ch said...

hi dr carlson ...

I realy like this episode ...
of caurse the cold things have more dansity then warm things but why a battle full of water explose if we let it a long time in the freezer?? ...the ice volume supposed to be less then the liquide ...or not ???


and why the air is cold in the high places ?? ...It's supposed to be warm ...like the experience in that video ...

I'm waiting your ansers dr ...

and thank you So much

Dr. Matt J. Carlson said...

A bottle will explode when frozen not because the glass shrinks, but because water expands when frozen. This is very strange, most things do NOT expand when they freeze.

Air is cold as you go away from the earth because you are farther from the earth (which is warm) and closer to space (which can be considered cold). Hot air does rise, but being further from the warm ground has a big effect.