1. atmosphere

2. Earth’s atmosphere reaches from Earth’s surface to 40,000 miles from Earth’s surface. The farther you travel from Earth’s surface the less and less air there is and therefore less and less air pressure. The farther you travel from Earth’s surface the sun’s radiation is more intense. Scientists have separated Earth’s atmosphere into layers based on temperature changes as you travel from one layer to the next.

4. THE ATMOSPHERE’S LAYERS ARE BASED ON TEMPERATURE CHANGES TROPOSHERE- lowest layer and most dense contains > 75% of atmosphere’s total mass where weather is found STRATOSPHERE- very thin and cold layer contains ozone layer which protects us from UV rays MESOSPHERE- coldest layer where meteors burn up THERMOSPHERE- warmest layer of atmosphere because it absorbs a great deal of solar radiation EXOSPHERE- layer where a few gas molecules have escaped earth’s gravity

5. LAYERS OF THE ATMOSPHERE Troposphere– highest content of oxygen, contains 75% of gases of the atmosphere, great amount of breathable air, water cycle, weather, meteors, sun’s radiation is absorbed, traps in heat Stratosphere– very cold, ozone layer absorbs dangerous UV radiation, sun’s radiation is absorbed, meteors, no breathable air Mesosphere– coldest layer, sun’s radiation is absorbed, most meteors burn up in this layer, no breathable air Thermosphere– warmest layer because it absorbs a great deal of the sun’s radiation, the sun’s very dangerous gamma and X rays are absorbed here, meteors, no breathable air Exosphere– a few gas molecules drift this far away from earth’s surface, meteors, sun’s radiation, no breathable air

8. Many materials can block gamma, x and UV rays. The denser the material the more effectively the rays will be blocked. Concrete, metals and even paper can block these rays. The most effective of these is metal because of its high density. The most effective metal is lead.

9. OZONE LAYER DOES NOT WARM UP THE PLANET OZONE LAYER  LOCATED IN STRATOSPHERE  BLOCKS HARMFUL ULTRAVIOLET RAYS  A THINNER OZONE LAYER, ALLOWS UV RAYS TO DAMAGE LIFE ON OUR PLANET  NO OZONE LAYER = DEATH OF LIFE GREENHOUSE EFFECT  GASES ( WATER VAPOR, OXYGEN, METHANE, CO2, ETC.) IN THE TROPOSPHERE TRAP IN HEAT  GREENHOUSE GASES ACT LIKE A BLANKET