Earth and Space Science / Unit 7: The Atmosphere and Weather
7.2 Heat Transfer and Energy Balance
Notes
Energy from the Sun heats Earth unevenly.
- Radiation: energy as waves (Sunlight). Conduction: heat through direct contact. Convection: heat carried by moving fluid; warm air rises, cool air sinks.
- Earth reflects about 30% of sunlight (albedo); clouds, ice and snow reflect more, dark ocean and forest reflect less.
- The greenhouse effect: gases like carbon dioxide, methane and water vapor absorb heat radiated by Earth and keep the planet warm. Without it Earth's average would be about -18°C.
- Land heats and cools faster than water.
Practice
Warm air rising and cool air sinking is an example of:
Convection moves heat by fluid motion.
Which surface has the highest albedo?
Snow reflects most sunlight.
The greenhouse effect is:
It is a natural effect that humans have strengthened.
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