1. The Atmosphere

2. Characteristics of the Atmosphere blanketIt is a blanket of moisture-filled air that surrounds the earth It consists 78% nitrogen, 21% oxygen, 1% other gases (argon, carbon dioxide and water) It has ozone in its upper layers which absorb harmful UV rays from the sun It protects us from meteors (they vaporize due to the friction with the atmosphere) SEE ALBERTA CLIPSEE ALBERTA CLIP It keeps the earth warm enough for us to live BRRRRRR!! DO YOU KNOW JUST HOW COLD SPACE IS!!

3. Layers of Atmosphere

4. Temperature Gradient A change in temperature over a distance ****In the troposphere the temperature gradient if -0.65°/100 m in altitude Example: What is the temperature at the top of an 8000 m mountain if the temperature is 18°C at the foot of the mountain?

5. Layers Again….

6. Layers in Order…(starting from the Earth upwards) 1. Troposphere – up approx 12 km Closest to the Earth’s surface Where all weather takes place Air is in constant motion with both vertical and horizontal currents Pressure decreases as altitude increases Has very small amounts of ozone 2. Tropopause Contains more ozone than troposphere Is warmer than the troposphere because it absorbs UV rays from the sun

7. 3.STRATOSPHERE 12-50 km above the Earth’s surface Higher levels of ozone than any other layer 4.MESOSPHERE Temperatures are very low here 50 to 80 km above the earth Very low density Meteors from space usually burn up in this layer due to air friction Temperatures are very low here

8. 5.Thermosphere AKA –Ionosphere 80 km to 500 km from Earth’s surface Fewest air molecules Also called ionosphere b/c the Sun’s radiation causes particles to become electrically charged ions The Northern and Southern lights (aurora borealis) are produced by these ions These charged particles also reflect radio signals so they can travel around the World

9. 6. Exosphere Outer limits! SPACE The thin, outermost layer Very few particles (few hydrogen particles) spread out very far -DISCOVERY COMMERCIAL