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Unit 9: Light Page 12
In our own atmosphere, light Are radio waves sound
travels slower than it does in waves?
space.
Radio waves are not
How do I study light? the same thing as
sound waves. Radio
Most light we can’t see with our
waves are low-energy
eyes, and that makes it hard to
light waves. Think
study.
about this: you can’t
hear the stuff coming off a radio
If you place your hand above
station antenna – you need a way
(carefully!) a burner on an electric
to transform the light waves into
stove as it heats up, you can
sound waves (which is exactly
detect the light coming from the
what your radio does). The sounds
stove long before it starts to glow
from a scream are vibrating air
red. You are detecting the infrared
molecules, while radio waves are
light using your skin.
actually light beams moving much,
much faster.
After a day at the beach, your
sunburn is the result of absorbing
How does a microwave
UV light.
work?
How do I detect light?
Your microwave
Your eyeballs are photon detectors. heats your dinner
These photons move at the speed by aiming very
of light and can have all different specific light
wavelengths, which correspond to beams at your food. The light
the colors we see. Red light has a beams excite the water molecule
longer wavelength (lower energy (which is present is nearly all
and lower frequency) that blue foods), and this energy makes the
light. water molecules jiggling around
faster (called heat). The energy
If you have a low-energy photon, from the light gets pumped into
you might perceive it as a radio your food. Which is why you never
wave by turning on your radio in want to run a microwave without
the car and ‘seeing’ what signals food inside, as it will ‘cook itself’
you can pick up. and blow up.
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