Light waves, visible and invisible - Lucianne Walkowicz

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Each kind of light has a unique wavelength, but human eyes can only perceive a tiny slice of the full spectrum -- the very narrow range from red to violet. Microwaves, radio waves, x-rays and more are hiding, invisible, just beyond our perception. Lucianne Walkowicz shows us the waves we can't see.

Lesson by Lucianne Walkowicz, animation by Pew36 Animation Studios.

What if you could only see one color?

Imagine, for instance,

that you could only see things that are red

and that everything else

is completely invisible to you.

As it turns out,

that's how you live your life all the time

because your eyes can only see

a minuscule part of the full spectrum of light.

Different kinds of light are all around you everyday

but are invisible to the human eye,

from the radio waves that carry your favorite songs,

to the x-rays doctors use to see inside of you,

to the microwaves that heat up your food.

In order to understand

how these can all be light,

we'll need to know a thing or two

about what light is.

Light is electromagnetic radiation

that acts like both a wave and a particle.

Light waves are kind of like waves in the ocean.

There are big waves and small waves,

waves that crash on the shore

one right after another,

and waves that only roll in every so often.

The size of a wave is called its wave length,

and how often it comes by

is called its frequency.

Imagine being a boat in that ocean,

bobbing up and down as the waves go by.

If the waves that day have long wave lengths,

they'll make you bob only so often,

or at a low frequency.

If the waves, instead, have short wave lengths,

they'll be close together,

and you'll bob up and down much more often,

at a high frequency.

Different kinds of light are all waves,

they just have different wave lengths and frequencies.

If you know the wave length or frequency

of a wave of light,

you could also figure out its energy.

Long wave lengths have low energies,

while short wave lengths have high energies.

It's easy to remember

if you think about being in that boat.

If you were out sailing on a day

with short, choppy waves,