Physical Science, Module 3, The Atmosphere

•What we did 2010
•Videos for this module


In learning about the atmosphere, I wanted to do a few more things about air this time as well as the experiments we did in 2010.  This post is only about the new ones.  =)
Air presses on us from all sides.  We don't feel it, but it is there.  That is why if you take a large, thin board and wave it in the air, you feel resistance.

Flatten an Index Card
I had the kids fold an index card in half and flex it a few times, then place it on the table so that it made a low "tent."  They could blow under it to make the tent flatten.
This was because blowing some air molecules from under the index card temporarily allowed the air above the card to have more pressure than the air under the card.

Rising Paper
I also had them place a short strip of paper on their chin and blow, causing air molecules above the strip to be temporarily displaced, making the strip of paper to rise.  This is also like air blowing over the wing of a plane.

Straw Fountain
The boys loved this one!
And as you may have guessed by now, this is because of pushing air molecules out of the way, allowing the air pressure that is pushing down on the water in the cup to be temporarily greater than the air pressure pushing down at the top of the straw.
(We taped the inside straws in place before adding water.)







Rebellious Paper Wad (p. 14)
This works if you tell the kids to blow HARD! =D




We also did the can crusher experiment from the 2nd edition, but we're using the first edition and had no directions except for things I found online, so maybe that was why this one didn't work like it was intended?
No crushing.

But... the can did suck up the icy water.
How?
Since the molecules in the can were hot, they were more spread out.
When we inverted the can into icy water, this cooled the molecules in the can, causing them to take up less space.  Since they took up less space, it drew the water up into the can.

LOL, the hot stove eye looks PINK!  How funny.


►Video of how it is supposed to work.
(You'll see my name under a comment, but my comment was apparently deleted... In case you're wondering what my name is doing there!)

►Find more air pressure experiments here.


sMiLeS,