1. Bellwork 4/4
1. What is air pressure? 2. Is air pressure being exerted on you right now? How do you know?

2. Can we feel air pressure?
What is air pressure?
Can we feel air pressure?
How do we measure air pressure?
How do we know it exists?

3. Quick Demo Stations: Visit each table and try the short activity
Follow directions, don’t make a mess
Be curious 

4. Atmospheric pressure Force exerted by the weight of the air above
Weight of the air at sea level
1 kilogram per square centimeter (also called “1 atmosphere”)
Decreases with increasing altitude
Units of measurement
Millibar (mb)
1mb = 100 Pascals= 1Newton/m2

5. Wind Horizontal movement of air
Moves from High Pressure Areas to Low Pressure Areas
Pressure differences are a result of the uneven heating of earth.
Solar radiation is the ultimate energy source for wind

6. 3 Factors that Affect Wind
1. Pressure gradient force
Pressure gradient = pressure change over distance
The greater the pressure difference, the greater the wind
Isobars: lines of equal air pressure
Measured in millibars
Bottle/Balloon Demo

7.  Closer the isobars are together, the faster the wind speed
 Faster winds = lower pressure
Bernoulli’s principle (Hair Dryer Demo)

8. Drawing Isobars

9. Wind Joke!

10. 3 Factors that Affect Wind
2. Coriolis Effect
Apparent deflection in the wind direction due to Earth's rotation
Deflection is the right in the Northern Hemisphere and to the left in the Southern Hemisphere

11. The Coriolis effect

12. 3 Factors that Affect Wind
3. Friction
Only important near the Earth’s surface— “Upper Air Winds” are not affected by friction.
Acts to slow the air's movement

13. The geostrophic wind

14. Practice:
Pressure Gradient:
Coriolis:

16. Million Dollar Bet
Take a small piece of the paper and make it into a small ball about the size of a large pea.
2) Set the bottle down on its side laying flat on a counter or table.
3) Place the paper ball in the mouth of the bottle.
4) Try to blow the ball inside the bottle.
What happens?
5) Bet your friends a million dollars if they can do it! (Not really.)

17. Mesh Magic! (no…it’s science)
Take the piece of mesh and cover the mouth of a bottle. Secure tightly with a rubber band.
Fill the bottle up with water.
Invert the bottle over a sink.
What happens?

18. Ping Pong Ball Bottle Fill the bottle up with water.
Place the ping pong ball over the mouth of the bottle.
With one finger on the ping pong ball, invert the bottle over a sink. Make sure no water is leaking from the mouth of the bottle.
Remove your finger from the ping pong ball.
What happens?

19. Funnel Fiasco
Use a large piece of paper to create a funnel. Make sure the small opening is small enough that the ping pong ball will not fall through.
Tape the paper in place.
Place the ping pong ball in the funnel. Hold the funnel completely vertically. Try to blow the ping pong ball out of the funnel.
What happens?
Make a smaller funnel and try the same thing.

20. Skewered Bottle
Fill a plastic cup with water. Stick a straw in the cup. Cover the opening of the straw with your finger. Lift the straw up with your finger still covering the opening. What happens?
Now, stick the skewer through the holes in a bottle.
Fill the bottle with water so that the water level is above the skewer.
Place the bottle in a tray. Slowly & carefully remove the skewer from the water bottle.
What happens?
Now, twist off the bottle cap.