1. What gas makes up 78% of our atmosphere?

2. Nitrogen

3. When a candle burns, what happens to the oxygen?

4. It is burned up.

5. The condition of Earth’s atmosphere at a particular time and place is called….

6. Weather

7. T or F
Smoke is made up of solid particles in the air.

8. True

9. What gas makes up 21% of our atmosphere?

10. Oxygen

11. The atmosphere protects us from harmful rays of the sun plus…..

12. meteoroids

13. Water vapor is a liquid and steam is a gas.

14. True

15. The more molecules in a volume of air, the greater it’s …..

16. Density

17. Plants take in carbon dioxide and give off ….

18. Oxygen

19. Air has mass because it is composed of …..

20. Atoms and Molecules

21. Density increases if we put ___ molecules in it.

22. More

23. The amount of oxygen is less at high or low altitudes?

24. High

25. What do we call an instrument used to measure air pressure?

26. Barometer

27. As air pressure decreases, what happens to the column of mercury?

28. It sinks

29. Mercury is one type of barometer. Name another type.

30. Aneroid

31. Inches of mercury is one way we express air pressure. What is another?

32. Millibars

33. What is another word for elevation?

34. Altitude

35. Air pressure is weakest.

36. On a mountain top