1. Heat Transfers: Convection
Quick DVD: Weather – Wind Chp 2 8:05
Hot Rises
Cold Sinks
Caused by density differences:
Hot air expands and gets less dense.
Cold air contracts and gets more dense.

2. A Convection Cell
Cool
Hot

3. Lesson 4: Air Pressure
The weight of the air above you. The more air that is above you the more pressure you will feel.
Sinking air pushes down more- cold air is usually high pressure.
Rising air pushes down less- hot air is usually low pressure.

4. Air Pressure

6. A Convection Cell
High
Pressure
Low
Pressure

7. Wind Wind travels from high pressure to low.
The gradient between isobars determines the wind speed.

8. Big Difference in Pressure
(Steep Gradient) H L

9. Small Difference in Pressure
(Gentle Gradient) H L

10. H

11. Isobars
Slowest Wind H
Fastest Wind

12. Low Pressure Sucks! L

13. L
Slowest Wind
Fastest Wind

15. The Coriolis Effect
The Coriolis Effect deflects things to their right in the Northern Hemisphere.
Caused by the rotation of the Earth.

16. H

17. Find where the High Pressure region is.

18. High Pressure flows outward and clockwise (cw) (in the N. Hemisphere)

19. L

20. Low Pressure flows inward and counterclockwise (ccw)(in the N
Low Pressure flows inward and counterclockwise (ccw)(in the N. Hemisphere)