Actually we have 14 p.s.i. (pounds per square inch.) That means every square (with sides only equal to one inch) on our body has almost 15 lbs pushing on it! Fifteen pounds is pretty heavy, just ask the bucket holder of the day!
When air pressure changes, amazing things can happen! It can make your Pringles lid bulge, prevent or cause storms, cause people to need oxygen masks, vacuum your carpet, make a plane fly, and squish a can.
Here are some ways to decrease air pressure:
- Get air moving quickly in one direction. This causes lift which allows planes to fly and us to lift a paper by blowing on top!
We moved air with a balloon pump. What will happen in this experiment?
-Heat air up. This causes the particles to spread out so there are less particles to push.
-Take a hike! The higher above see level you are, the less particles there are to push on you (and to breathe in.)
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| I can't breathe well on top of this mountain! |
Today we used air pressure to smash a can.
First we got a can, put a little water in it.
Then, we heated the can on a hot plate.
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| The molecules heat up and move faster. They have more pushing power moving faster, so the pressure is equal inside the can and out. |
Next we took tongs and turned it upside down cold water sealing off the opening.
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| Because the few molecules left in the can quit moving quickly (because they got cold), they didn't push on the can as strongly. The pressure inside the can was less then the outside air pressure. The outside air pressure crunched the can! |
Watch a video of our demonstration!
Now watch Steve Spangler crush a 55 gallon drum!
Here is an easy experiment from Science With Kids you can try at home. It is similar to the one of the wet tub experiments we did at school today.
Air pressure experiment
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