Chapter 12 - Earth's Atmosphere - Part 2

Conduction

Conduction is the transfer of thermal energy by particles that are touching. Conduction usually occurs where the atmosphere touches the Earth. Roasting marshmallows over a fire and the heat going up your hand from the stick is an example of conduction.

Convection

Convection is the transfer of thermal energy by the movement of particles within matter. When the air molecules close to the Earth's surface are heated by conduction, they spread apart and the air becomes less dense. The less dense air then soon rises, transferring thermal energy to higher altitudes.

Radiation

Radiation is the transfer of energy by electromagnetic waves through space, from the Sun to the Earth.

Temperature Inversion

Temperature occurs in the troposphere, where temperatures increase, as altitude increases. This occurs when ground level air is almost the same temperature as higher-altitude air. The air is also more stable and convection currents are weak. The layer of warmer air is trapped by a layer of warmer air above it, which prevents air from mixing and trapping pollution in the air close to Earth's surface.

Greenhouse Effect

The Greenhouse Effect is the process where gases in the atmosphere absorb and reradiate thermal energy from the Sun. The land, water, plants, and other organisms absorb solar radiation, reaching Earth's surface. The radiation is absorbed by Earth and bounces back, into the atmosphere, which is in the form of Infrared Radiation (IR), where it heats up the atmosphere. Greenhouse gases prevent some of the Earth's IR energy from escaping, it traps it and directs it back to Earth's surface, which causes a buildup of thermal energy at Earth's surface.