Movie Review

1
Movie Review
2
What is a barometer?

• A barometer is a device that measures atmospheric
  pressure remember the atmosphere has pressure
  because air has weight.
• This is just like water pressure!
• Why do we use barometers?
• Weather forecasting
• Measuring altitude
• How do barometers work?
• Atmospheric pressure pushes the liquid up the
  tube
• A straw is very similar to a barometer.

3
How does a straw work?

• Could you drink from a straw on the moon?

4
What is this 10.3m?

• In yesterdays video, Paul Hewitt constantly
  referred to 10.3 m. Why is this number
  important?
• A barometer made of water would need to be at
  least 10.3 m tall for normal atmospheric
  pressure.
• The longest straw you could use to drink water is
  also 10.3 m.
• If any object is 10.3 meter below the surface of
  water, the total pressure has doubled on the
  object.
• And, under Boyles law the volume would be cut in
  ½.

5
Ideal Gas Law Boyles Law

• Boyles Law P1V1 P2V2
• temperature is constant
• Ideal Gas Law
• temperature must be in Kelvins
• http//phet.colorado.edu/simulations/sims.php?sim
  Gas_Properties