| Air Pressure | The total force exerted on any surface by the molecules in the air. Another term used is Barometric or Atmospheric Pressure. |
| Altitude | Height of an object in relation to a given point such as sea level or the horizon. |
| Atmosphere | A thin envelope of gases that encircle the globe. The atmosphere also contains suspended solid and liquid particles and clouds. |
| Barometer | An instrument used to measure changes in air pressure. |
| Cold Front | A narrow zone of change between relatively cold, dense air that is advancing and relatively warm, less dense air that is retreating. |
| Molecule | Smallest fundamental unit of an element or compound. |
| Tornado | A small but intense cyclonic vortex in which air spirals at tremendous speed. |
Weather definitions taken from:
Morgan, J., Morgan, M., (1989) Meteorology: The Atmosphere and
the Science of Weather, 2nd ed., Macmillan Publishing Company.
