| A | B |
|---|
| Humidity | the moisture content of air |
| Absolute humidity | the mass of water vapor contained in a certain volume of air |
| Relative humidity | the ratio of the mass of water vapor in the air at a given temperature to the maximum mass of water vapor the air could hold at that temperature; expressed as a percentage |
| Greenhouse effect | the process by which certain gases (water vapor, carbon dioxide & methane) trap heat that radiates from earth |
| Parts per million | The number of molecules (or atoms) of a substance in a mixture for every 1 million molecules (or atoms) in that mixture |
| Nitrogen | What makes up the majority of the air we exhale |
| Oxygen | Do we exhale more carbon dioxide or more oxygen? |
| Ozone | Although this is poison and we don't want to breathe it, we need it to block the ultraviolet light coming from the sun |
