Download Radiant Energy

Light Energy
Energy given off by electrons.
It travels in waves, and can travel through
space.
• Light is a form of electromagnetic radiation, a
combination of electrical and magnetic energy
Radio Waves
• Radio waves can be
longer than a football field
or as short as a football
• Used for TVs, radios, and
cell phones to transmit
information
Microwaves
• Wavelengths can be measured in
centimeters
• Microwave ovens use wavelengths
close to a foot in length
• Good for transmitting information
because microwaves can penetrate
haze, light rain, cloud and smoke.
• Used in radars, like doppler radar
for sensing weather forecasts.
Infrared Rays
• Longer infrared rays have wavelengths about
the size of a pinhead; these longer rays are
thermal. Experience everyday in the form of heat!
– Some animals, like vipers, can see infrared
• Shorter rays are about the size of cells. These
aren’t hot; used in TV remotes.
• People, animals, stars, galaxies all emit infrared
Visible Light
• Only radiant energy
we can see
• All wavelengths see
together make white
light
• ROY G BIV
Ultraviolet Light (UV Rays)
• Can’t see with the human eye,
but some insects, like
bumblebees can see them!
• Sun emits light at all
wavelengths. But UV rays are
responsible for sunburns
• Most are blocked from entering
by the ozone layer
• Scientists use UV rays to detect
stars and galaxies
X-rays
• X-rays can travel through
skin
• But things like bone, metal,
or teeth are more dense
than skin, and thus absorb
the X-rays. X-rays show us
a “shadow” of these denser
materials.
• Many things in space emit
X-rays: black holes, stars
(like the Sun and others),
supernova remnants,
comets!
Gamma rays
• Gamma rays have the
smallest wavelengths,
and they have the most
energy
• Generated by
radioactive atoms,
nuclear explosions, or
supernova explosions
• Can kill cells
– Used to kill cancerous
cells or kill bacteria on
fruit
Gamma Ray Gun (NOTE: This is
not real!!!)