| A | B |
|---|
| atmosphere | A blanket of gases that surrounds Earth |
| troposphere | The densest layer of the atmosphere, closest to Earth's surface; most of the gas in this layer is nitrogen and oxygen; layer in which most of our weather takes place |
| stratosphere | The layer of the atmosphere that lies above the troposphere; protective ozone layer is located in this layer |
| ozone | A molecule containing three atoms of oxygen |
| ozone layer | A layer in the atmosphere that contains a hight concentration of ozone molecules that protects life on Earth by absorbing UV rays from the Sun |
| mesosphere | The layer of the atmosphere that lies above the stratosphere; extremely cold; meteors burn in this layer |
| thermosphere | The layer of the atmosphere that lies above the mesosphere; contains charged particles (ions); auroras occur here |
| exosphere | The layer of the atmosphere that forms the outer edges of the atmosphere; extremely thin; mainly hydrogen and helium |
| pollutants | A substance or material that is harmful to the ecosystem |
| air pressure | The downward force exerted by air |
| barometer | An instrument that measures changes in air pressure from day to day |
| cyanobacteria | Photosynthetic organisms that produce oxygen. According to the big bang theory these organisms introduced oxygen into the Earth's atmosphere, allowing evolution to occur. |
| particular matter | Tiny pieces of solid matter, including dust, ash, pollen, and salts, in Earth's atmosphere |
| altitude | The height above sea level |
