Same family, different size
Is Radio Really a Kind of Light?
Radio waves are light with very long waves, which is why they behave so differently from what we see.
-
Step 1 of 5
Light is a wave of electricity and magnetism.
Visible light is a ripple in electric and magnetic fields travelling through space, and nothing about it requires a material to carry it.
-
Step 2 of 5
Our eyes only respond to a narrow slice.
The waves we can see span less than a thousandth of a millimetre in length. Everything outside that band exists but is invisible to us.
-
Step 3 of 5
Radio is the same wave, enormously stretched.
Stretch the wave from a fraction of a millimetre out to metres and you have radio. It is not a different thing, only a different size.
-
Step 4 of 5
Long waves pass through things easily.
A wave much larger than an obstacle tends to flow around it, which is why radio reaches through walls that stop visible light completely.
-
Step 5 of 5
The whole family is one continuous range.
Radio, microwave, infrared, visible, ultraviolet, X-ray and gamma are all the same wave at different lengths, with no gaps between them.
An FM radio wave is about three metres long, while green light is around half a millionth of a metre.
The short version
Radio is genuinely light, stretched to waves metres long, and that length is why it passes through walls that stop what we can see.
Try it yourself
Notice that a radio keeps working inside a building but a torch beam cannot get through the wall. Same family, different wave length.
Topics