Ouch! You went swimming all day and forgot to put on more sunscreen after you got out of the water. Now you have stinging sunburn. How did you get it? Your sunburn came from light, but not from light that you can see.
When all the colours in sunlight are separated, they make a rainbow. The rainbow has a band of red on one edge and a band of violet on the other edge. In between are all the other colours. But beyond the red edge and the violet edge, there are “colours” you do not see.
A suntan or painful sunburn both come from ultraviolet rays. Ultraviolet means “beyond violet”. Ultraviolet rays are just beyond the violet edge of the rainbow. You cannot see these rays. But when your skin gets tanned or burns, you see what ultraviolet energy can do.
The heat you feel when the sun is bright comes from infrared rays. Infrared means “below red”. Infrared rays are just below the red edge of the rainbow. Like ultraviolet rays, these rays can’t be seen either. But you can feel them. When they hit something, the energy they give off makes that object heat up. Pavements get hot in summer because they absorb energy from the sun’s infrared rays.
Picture Credit : Google