http://www.youtube.com/watch?v=DOAqECd70Ww&safe=active
3:35 The Earth’s Energy Balance
The Earth’s Radiation Budget
The Earth’s Radiation Budget is how much of the
sun’s energy is absorbed by the earth versus
how much of it is reflected back out to space.
Approximately 71% is absorbed in total (23 + 48)
• If the Earth and it’s atmosphere keep more
solar energy than it sends back to space, the
Earth will warm up.
• If more energy is sent back to space than is
kept by the Earth and it’s atmosphere, the
Earth will cool down.
• Scientists think of the
Radiation Budget in
terms of a see-saw or
balance.
• When absorbed sunlight
and reflected energy
balance each other, the
Earth's temperature
doesn't change - the
radiation budget is in
balance.
30%330%
30%
The Ozone layer filters out/reflects many of
the sun’s harmful rays and prevents some
sunlight from reaching the earth.
OZONE LAYER
EARTH
Greenhouse effect
http://www.youtube.com/watch?v=3JX-ioSmNW8&safe=active
2:03 Greenhouse Gases: Climate Change, Lines of Evidence
Climate Change
• The temperature of the planet depends on the balance between how
much of the sun’s radiation is absorbed by the earth vs. how much is
reflected.
• The trapped heat keeps the planet warm and the heating process is called
the greenhouse effect. The greenhouse effect has been crucial to
maintaining earth’s energy balance and temperature throughout its
history, making the planet habitable.
• Recently, scientists have concluded that earth’s energy system is out of
balance, as increasing concentrations of greenhouse gases are causing
additional heat to be absorbed.
• As of 2007, scientists are over 90% certain that human-caused greenhouse
gas emissions have caused the global increase in average temperature by
about 1oC since the mid-20th century.
The Electromagnetic Spectrum
• The heat produced by the Sun travels to the
Earth as waves known as electromagnetic
waves.
• The electromagnetic waves come in a variety
of lengths.
• The name given to the full range of all the
wavelength is the electromagnetic spectrum.
ROYGBIV
The EM Spectrum
http://www.youtube.com/watch?v=cfXzwh3KadE&safe=active
The Electronmagnetic Spectrum 5:20
Interactive Worksheet
• “Reading Comprehension Pages” p 43
•
(http://education.jlab.org/reading/energy_budget.html) link to above