The highest layer in the atmosphere, where atoms absorb solar energy resulting in warming of the air to as high as 3,600 F.

Force that air exerts over a certain area due to it's weight or motion.

atomic mass unit, the unit used to measure the masses of subatomic particles; a proton has a mass of 1 amu.

The smallest part of an element that has all the properties of the element.

A temperature scale where water freezes at 0º C and boils at  100º C.

A visible collection of very fine water droplets or ice crystals suspended in the atmosphere at altitudes from just above the ground to several miles above the sea level.

The process by which a gas or vapor changes to a liquid.

Tiny particles invisible to the human eye, such as dust, dirt, and pollutants, that provide surfaces on which water molecules can condense and gather into water droplets.

The transfer of heat within a substance or from one substance to another as a result of molecular motion. Always from warm to cold areas.

The transfer of energy and mass by motions in a liquid or gas. In the atmosphere, convection usually refers to the vertical interchange of air masses. An example of convection is the rising of warm su [..]