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VISIBLE LIGHT
The Sun emits most of its
energy as visible light, which
can be split into the colours
of the rainbow. Earth’s
atmosphere allows visible light
through, while blocking more
harmful wavelengths. Visible
light is vital for life. Without
it, plants could not grow.
INFRARED RAYS
Just beyond the visible red in
the spectrum is infrared, which
can be felt as heat. Often,
when heat energy moves
it is transported by infrared
waves. Infrared satellite images
of Earth’s surface are used
by weather forecasters to
determine temperatures.MICROWAVES
These have much longer
wavelengths than visible
light. Longer wavelength
microwaves are used in a
microwave oven. Shorter
wavelength microwaves are
used in radar systems that help
ships and planes navigate by
locating traffic and obstacles.RADIO WAVES
These are the longest in
the spectrum. Many forms of
communication, such as TV, mobile
phones, and radio, use radio
waves, with different wavelengths
carrying different signals. Radio
waves from outer space are picked
up by radio telescopes and used in
studies of the Universe.112_113_electromagnetic.indd 113 10/01/19 2:26 PM