1. Thunderstorms Chapter 3 Section 2 Pages 83-85 Chapter 3 Section 2 Pages 83-85

2. Stormy Weather StormA Storm is a violent disturbance in the atmosphere –Involve sudden changes in air pressure –Causes rapid movement of air.

3. Heavy rain storms (and sometimes hail), accompanied by thunder and lightning cumulonimbus clouds Form within large cumulonimbus clouds or thunderheads. Thunderstorms

4. How Thunderstorms Form 1.Warm, humid air is forced upward at a cold front –Air rises rapidly 2.Cools and forms a dense cumulonimbus cloud.

5. Lightning Positive and negative charges build up in the storm clouds from friction of ice crystals Lightning is the sudden discharge of this built up energy cloud to cloudcloudtoground. –May occur cloud to cloud OR cloud to ground.

7. Thunder hotter than the sun’s surface! Lightning super-heats the air around it to 30,000°C (hotter than the sun’s surface!) The rapidly heated air expands suddenly and explosively –Thunder is the sound of the explosion –Thunder is heard after lightning because light (299,792,458 m/s) travels faster than sound (340.29 m/s).

8. Thunderstorm Safety If outside: –Avoid touching metal objects because they conduct electricity –Lightning usually strikes the tallest objects Trees, house or flag poles.

9. Thunderstorm Safety If outside in an open area: –Find an area low away from trees, fences and poles –Crouch down with your head down and hands on your knees –If swimming or on a boat, seek shelter away from the water.

10. Thunderstorm Safety If inside: –Avoid touching phones, electrical appliances, or plumbing. They conduct electricity –Cars are safe because they carry electricity around the metal shell, but do not touch metal in the car.

11. Exit Pass How does electric charge build up in clouds? What causes the sound of thunder?