Download Electromagnetic Spectrum

Electromagnetic
Spectrum:
Notes in order of lowest
frequencies to highest
frequencies
• https://www.youtube.com/watch?v=cfXzwh3
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• https://www.youtube.com/watch?v=m4t7gTm
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Electromagnetic Spectrum
• Radio Waves
• Microwaves
• Infrared Rays
• Visible Light
• Ultraviolet Rays
• X Rays
• Gamma Rays
Radio Waves
• Longest wavelengths
• Lowest frequencies
• Broadcast waves: carry signals for both
radio and television programs.
• This includes transforming into electrical
signals in a radio or pictures and sounds
for a TV.
Microwaves
• The radio waves with the shortest
wavelengths and highest frequencies.
• Microwave ovens cook and heat your
food.
• Also used in cellular phone
communications and radar.
• Radar: radio detection and ranging.
• A radar is a system that uses reflected
radio waves to detect objects and measure
their distance and speed.
Infrared Rays
• The invisible heat you feel in infrared
radiation or infrared rays.
• Have shorter wavelengths and higher
frequency than radio waves so they
have more energy.
• Often called heat rays because you feel
infrared rays as heat.
• Most objects give off some infrared
rays.
• Warmer objects give off infrared waves
with more energy and higher
frequencies than cooler objects.
• A thermogram is an image that shows
region of different temperatures in
different colors.
• Infrared cameras are used to see objects
in the dark.(Firefighters use them to
locate victims inside dark or smoky
building)
• Satellites in space use infrared cameras
to study the growth of plants and the
motions of clouds.
Visible Light
• Electromagnetic waves that you can see.
• Shorter wavelengths and higher
frequencies than infrared rays.
• The longest wavelength appear red in
color.
• Visible light that appears white is
actually a mixture of many colors.
• White light from the sun can be
separated by a prism into the colors of
the visible spectrum(ROYGBIV)
• Red light waves refract the least and
Violet light waves refract the most.
Ultraviolet Rays
• Have higher frequencies than visible light.
• Carry more energy.
• This energy is great enough to damage or
kill living cells.
• Small doses of UV rays are useful. They can
cause skin cells to produce Vitamin D.
• To much exposure can be harmful: burn
your skin, cause skin cancer, and damage
your eyes.
X Rays
• Carry more energy than UV rays and can
penetrate most matter.
• Dense matter, such as bone or lead,
absorbs X-rays and does not allow them
to pass through.
• Used to make images of bones inside
the body or teeth.
• To much exposure can cause cancer.
• Dentist use lead aprons to absorb x-rays
from reaching your body.
• Sometimes used in industry and
engineering to examine the internal
structure of buildings.
Gamma Rays
• Shortest wavelengths
• Highest frequencies
• Most penetrating of all electromagnetic
waves.
• Produced by some radioactive
substances and certain nuclear
reactions.
• Have some medical uses: can be used
diagnose and kill cancer cells inside the
body.
• Some objects in space, such as
explosions of stars, give off burst of
gamma rays but they are blocked by the
Earth’s atmosphere.