What is the atmosphere? What is the composition of the atmosphere? Why is Earth’s atmosphere important? How does the Earth’s atmosphere exist? How was Earth’s atmosphere created? Why does Mercury not have an atmosphere? How does Venus’ atmosphere make it the hottest planet? How does oxygen get into the atmosphere?

Do Now 1/21/14 A ________ is a steep walled, pointy, extinct volcano found on the ocean floor. What is the name of the warm ocean current off our coast? The Mid-Atlantic Ridge is an example of a ___________ boundary. Name 3 examples of mass wasting.

1) What is the atmosphere? A very thin layer of gases that surrounds the planet. Atmosphere comes from 2 Greek words Atmos - means vapor sphaira - means ball or globe atmos sphaira

2) What is the composition of atmosphere? Nitrogen Oxygen Water Vapor Other Gases

3) Why is the Earth’s atmosphere important? Gives us oxygen and other gases Traps Sun’s energy and keeps Earth warm enough for water to exist as a liquid Protects us from dangerous radiation from the Sun Prevents us from being hit by meteorites and asteroids.

4) Why does the Earth’s atmosphere exist 4) Why does the Earth’s atmosphere exist? Earth’s atmosphere exists because Earth has the right mass and distance from the sun.

5) How was the Earth’s atmosphere created? Sun’s heat blew away light gases. Earth cooled and volcanoes spewed out steam, carbon dioxide, nitrogen. Earth’s gravitational pull held gases and early life forms began to make oxygen. Atmosphere was created.

6) Why does Mercury not have an atmosphere? Mercury is too close to the sun (too warm) and too small (not enough gravity) to have an atmosphere

7) How does Venus’ atmosphere make it the hottest planet? Venus is the hottest planet because its atmosphere is made of mostly carbon dioxide and heat is trapped.

8) How does oxygen get into the atmosphere? Oxygen gets into the atmosphere through photosynthesis Plants take in carbon dioxide and release oxygen