Science

3. A push or pull; something that changes the motion of an object.
7. Clear, dry layer; contains ozone layer.
9. A gas molecule that consists of three oxygen atoms.
10. A force that resists the motion between two surfaces in contact.
14. Energy that travels across distances as certain types of waves.
15. The resistance of an object to a change in the speed or the direction of its motion.
16. We live here; weather occurs here; contains 80% of the atmosphere's mass.
17. A colorless, odorless, tasteless nonflammable gas; 21% of atmosphere.

1. A tropical low-pressure system with winds of 74 mph or more.
2. Coldest layer; meteors burn up here.
4. Basic unit of matter; smallest component of an element.
5. Hottest layer of the atmosphere where the air is very thin, but can feel cold.
6. The force that objects exert on each other because of their masses.
8. The transfer of energy from place to place by the motion of heated gas or
11. The transfer of heat energy from one substance to another through direct contact.
12. The amount of water vapor in the air.
13. A colorless, odorless, tasteless gas; 78% of atmosphere.