5/18/10
Different ways to heat the Earth
Convection
•  Convection
– Transfer of heat in a liquid or a gas due to
movement of currents with in the substance
•  Movement occurs due to change in density
•  Conduction
•  Radiation
Conduction
•  Transfer of heat from one object to another
by direct contact
–  ie) hot glass sitting outside in winter, cools to temp
of atmosphere
• H ot fluid; low density
• R ise to top
• C ool fluid; high density
• Sinks to bottom
Radiation
only way energy can travel through space
•  Transfer of energy through space in form of:
•  Electromagnetic waves
– Ultraviolet rays
– Visible light
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5/18/10
How do Radiation, Convection,
Conduction work together
•  The sun radiates energy to earth which in
turn heats up our atmosphere and water
•  Through this hot air/water rises creating a
circular motion
Heating of the Earth
•  Land and water heat up and cool
down at different rates
Land at different latitudes
•  Farther from equator
– Less energy received (indirect rays)
•  Closer to equator
– Water heats up and cools down at a slower
rate
- Energy warms first few cm of land however
shines down several meters in water
More energy
received
(direct rays)
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