Sect. 2, Ch. 1
How long does it take for the energy from the sun to reach Earth?
Roughly 8 minutes and 20 seconds.
The Earth receives energy from the sun by radiation. Radiation is the transfer of energy as electromagnetic waves. Earth receives only about two-billionths of the energy radiated by the sun. About 50 % of the sun’s energy actually reaches earth’s surface.
Thermal conduction is the transfer of energy through a material. Example is touching a hot pan on a hot stove. Thermal energy is always transferred from warm to cold areas.
Convection is the transfer of thermal energy by the circulation or movement of a liquid or gas (fluids).
The warming of the surface and lower atmosphere of Earth that occurs when water vapor, CO2, and other gases absorb and reradiate thermal energy. Greenhouse gases function like the glass walls of a greenhouse which allow solar energy to enter but prevent thermal energy from escaping.
A gradual increase in average global temperature. Theory that increased greenhouse gases created by humans is increasing the greenhouse effect leading to warmer temperatures world wide. Burning of fossil fuels and deforestation are the main contributors.