Longer Wavelength
Gamma
Rays
X-Rays
Ultraviolet
Waves
Visible Light
Infrared
Waves
Microwaves
Radio
Waves
The Electromagnetic Spectrum KEY
Shorter Wavelength
Lower Frequency
Higher Frequency
LOW ENERGY
HIGH ENERGY
R
O
Y
G
B
I
V
Light travels in waves. There are many more types of light than what we can see;
everything besides visible light is invisible to the naked eye.
Radio Waves
Radio waves have the longest wavelengths in the electromagnetic spectrum. These waves can
be longer than a football field or as short as a football. Radio waves do more than just bring
music to your radio; they also carry signals for your television and cellular phones.
Microwaves
Microwaves have wavelengths that can be measured in centimeters! These are the waves that
heat our food in a microwave oven – they are easily absorbed by water. Water particles in food
quickly absorb the microwaves and vibrate, which causes our food to heat up.
Infrared
Visible Light
Ultraviolet
X-Rays
Gamma Rays
The warmth that we feel from sunlight, a fire, a radiator, or a warm sidewalk is infrared – heat
radiation. Motion detectors (burglar alarms) use changes in heat to detect movement. Short
infrared waves are used in your TV’s remote control.
Visible light waves are the only electromagnetic waves we can see. We see these waves as the
colors of the rainbow (ROYGBIV). Each color has a different wavelength. Red has the longest
wavelength and violet has the shortest wavelength. When all the waves are seen together, they
make white light.
Ultraviolet (UV) light has shorter wavelengths (higher energy) than visible light. Though these
waves are invisible to the human eye, some insects, like bumblebees, can see them! UV is
emitted by our sun and can be harmful to our cells – the ozone layer of our atmosphere helps
protect us from these.
X-rays have extremely high energy and can easily penetrate through skin and muscle. This is
how medical professionals are able to take pictures of the inside of your body!
Gamma rays have the smallest wavelengths and the most energy of any other wave in the
electromagnetic spectrum. These waves are generated in nuclear explosions. Gamma rays can
kill living cells, a fact which medicine uses to its advantage, using gamma-rays to kill cancerous
cells.