1. Warm Up
1. If warm air rises, where on the Earth do you think this process would happen the most?
2. Rising warm air transports heat energy by
Conduction
Convection
Radiation
Condensation

2. Winds
p. 472 – 477 in 6th grade textbook

3. What Causes Wind?
A wind is the horizontal movement of air from an area of high pressure to an area of low pressure.
All winds are caused by differences in air pressure.

4. What Causes Air Pressure Differences?
Caused by uneven heating of the Earth’s surface (direct and indirect light!)

5. Low Air Pressure
Areas that get lots of heat on Earth’s surface (EQUATOR) have hot air with low density  low air pressure

6. High Air Pressure
Areas that do not get a lot of heat (THE POLES) have colder air with high density  high air pressure

7. When Warm Air Meets Cold Air…
Cold air is more dense and has a higher air pressure, so it flows UNDER the warm air. This forces the warm air to rise.

8. Talk About it - Checkpoint!
Winds blow from areas of __________ pressure to areas of ________ pressure.
High pressure - ___________ temperatures
Low pressure - ____________ temperatures

9. Global Convection Currents
Warm air rises at the equator (lower air pressure here!)
Cold air sinks at the poles (higher air pressure here!)
This pattern forms giant convection currents in the atmosphere!

10. Global Winds
Winds at Earth’s surface blow from the poles (HIGH PRESSURE) to the equator (LOW PRESSURE)
Higher in atmosphere, winds blow from the equator to the poles.
The movement of air between the equator and poles produces global winds.

11. This is a Simplified Diagram!

12. Talk About It Why does hot air rise in the atmosphere?
Where does hot air rise on the Earth?

13. Giant Convection Currents

15. The Coriolis Effect
Wind would blow in a straight line if the Earth didn’t rotate
Because the Earth rotates, wind blows in a curved pattern

16. Coriolis Effect
The way Earth’s rotation makes the winds curve is called the Coriolis Effect.

17. The Coriolis Effect
In the Northern Hemisphere, winds turn to the right
In the Southern Hemisphere, winds turn to the left