1. Weather
Part 2
The Air We Breath

2. What three things must all living things have to live?

3. Food to eat, water to drink, and air to breath.

4. With out food we would die in a few weeks...
but without air we would all die in just a few minutes.
without water a few days...

5. Our ATMOSPHERE is the layer of air that surrounds our planet.

6. The atmosphere surrounds the Earth and protects us by blocking out dangerous rays from the sun.

7. The atmosphere is made entirely of gas
The atmosphere is made entirely of gas. It is composed mostly of nitrogen (78%), and oxygen (21%).

8. The last 1% is made of other gases like helium, carbon dioxide, water vapor, and many more.

9. Even though we can’t see air it is there. It even has weight
Even though we can’t see air it is there. It even has weight. As we sit in the room air is pushing down on us at a rate of 15 pounds per square inch.

10. In other words it is like having a 15 pound brick sitting on our heads
In other words it is like having a 15 pound brick sitting on our heads. How is this possible?

11. Less Dense
More Dense
Our atmosphere extends up for many miles. If we were to look at a column of air, the particles on top would be few and far between.

12. The particles on the bottom would be very close together or dense.
Less Dense
More Dense
The particles on the bottom would be very close together or dense.

13. Excuse me Human Teacher
Excuse me Human Teacher... As usual I don’t think they understand what you are talking about.

14. Micro humans, please listen closely and follow my directions...

15. Everyone get in groups of 6 people.

16. Stack your right hands on top of each other.

17. Now add your left hands to the stack in the same order.

18. Humans with their hand on the bottom
Humans with their hand on the bottom... Compare your right hand to your left. What do you observe?

19. Provide input now please...

20. Human who has their hand on the top
Human who has their hand on the top... Compare your right hand to your left. What do you observe?

21. Provide input now please...

22. Now one person at a time, move the hand on the bottom to the top of the stack.

23. Repeat until the bottom hand has returned to the bottom of the stack.

24. Notice how the pressure increases as your hand moves down the stack.

25. Imagine what your hands would feel like if you had a 320 mile stack of hands on top of you.

26. From the ground to the top most extreme of our atmosphere is about 320 miles.

27. Alright human teacher, I believe your students have assimilated the required knowledge. You may teach again...

28. Less Dense
More Dense
Things push down from the top. So the air molecules closest to the ground are very dense and close together.

29. The amount of air pressing down on the surface is called AIR PRESSURE.
Less Dense
More Dense
The amount of air pressing down on the surface is called AIR PRESSURE.

30. Less Dense
More Dense
The lower you are to the ground the higher the air pressure. The higher in the sky you go the lower the air pressure.

31. Exosphere Thermosphere Mesosphere Stratosphere Troposphere
The Earth’s atmosphere is divided into Five layers:.
Thermosphere
Mesosphere
Stratosphere
Troposphere

32. In the Exosphere, the Earth's atmosphere becomes very thin
In the Exosphere, the Earth's atmosphere becomes very thin. At the top of the Earth’s atmosphere, atoms and molecules escape into space.

33. The Thermosphere is the fourth layer of the Earth's atmosphere.

34. It is found above the Mesosphere. The air is really thin that high up.

35. The thermosphere is almost 400 KM thick.

36. During the day temperatures in the thermosphere can get up to 1,500°C or higher!

37. The Mesosphere is the third layer in the atmosphere.

38. In the mesosphere temperatures can get as low as -90º C.

39. If you look at the edge of the planet you can see the mesosphere.

40. The STRATOSPHERE is the second layer of the atmosphere.

41. The stratosphere is about 40 KM thick.

42. Ozone causes the temperature to go up as you climb higher
Ozone causes the temperature to go up as you climb higher. It absorbs dangerous light from the Sun and converts it to heat.

43. The TROPOSPHERE is the lowest layer of the Earth's atmosphere.

44. The TROPOSPHERE extends from the ground to about 10 KM in the sky.

45. The surface of the Earth absorbs energy and heats up faster than the air does.

46. Thus the air in the troposphere is heated from the ground up.

47. The heat is spread throughout the troposphere because the air is slightly unstable.

48. In other words... The wind blows and spreads the heated air around the troposphere.

49. Weather occurs in the Earth's troposphere.

50. The troposphere is where we live!

52. True 1) True or False - We live in the stratosphere.
False - Troposphere
2) True or False - The troposphere has the greatest air pressure of all the layers in our atmosphere.
True
3) The top layer of the atmosphere is called the biosphere.
False – Exosphere
4) The mesosphere is the layer in which where weather occurs.
False - Troposphere

53. Have a good evening students…