1. Pop quizzes 1.The sun’s heat travels to Earth by _________. 2.What percent of our atmosphere is made of oxygen? 3.What percent of our atmosphere is made of nitrogen? 4.What happens to the air on Earth when it heats up? 5.What powers all of our weather on Earth?

2. WEATHER UNIT

3. I. WEATHER AND ATMOSPHERE

4. A. What is weather? Weather is the condition of the atmosphere at a certain time and place.

5. B. What drives our weather? 1. The heat from the SUN is the driving force of our weather!! HOW? 2.As the sun’s solar energy heats the ground by radiation, the ground heats the air closest to the ground by conduction. As the air heats up, it becomes less dense and rises creating convection currents. Then cooler more dense air from elsewhere flows in to replace it. It’s like a giant Ferris wheel!

6. What happens to all of the sun’s radiation… 35% - reflected back into space 65% - absorbed by the atmosphere or surface.

7. 3. Due to convection currents… -warm air near the ground (that has been heated from the Sun’s energy) rises creating an area of low pressure. It’s called low because the air is not pushing down on the surface of the Earth…it’s rising. -When cooler more dense air sinks or falls to fill the area, it pushes down on the Earth’s surface pressing on the air beneath it. This is called a high pressure.

8. Sun heats up ground LOW PRESSURE LOW PRESSURE LOW PRESSURE Air heated by contact with ground expands; becomes less dense and rises Denser air drawn in at low level to replace rising, less dense air Draw This!!! How Convection Currents Occur

9. Hot Air Rises, Cool Air Sinks..…it’s a constant cycle!!

10. C. What is the atmosphere? -mixture of gases that surround the Earth -made of nitrogen (78%), oxygen (21%), and other gases(1%)

11. D. Layers of the Atmosphere 1. Troposphere -this is where all plants and animals live and breathe -where all weather takes place

12. 2. Stratosphere – the ozone in this layer stops many of the sun's harmful rays from reaching the earth - people can not breathe in this layer.

13. 3. Mesosphere -this is where we see meteors burning up as they fall to Earth (sometimes called shooting stars)

14. 4.Thermosphere (includes Ionosphere) 5.Exosphere

16. Let’s look at an animation:  http://earthguide.ucsd.edu/earthg uide/diagrams/atmosphere/index. html http://earthguide.ucsd.edu/earthg uide/diagrams/atmosphere/index. html http://earthguide.ucsd.edu/earthg uide/diagrams/atmosphere/index. html