I want you to imagine standing on a beach watching the waves just roll on it.

Why? Well, one, because I could really use a beach vacation,

and I hope you take me with you in this imagined world of ours,

and so we can enjoy it together.

And two, it's a metaphor.

But not really a metaphor, because it's a real thing in and of itself,

but it will also help us understand something that we can't imagine when

we're standing around and watching waves roll in on the beach. So does that count as a half metaphor?

I'm not exactly good, but it doesn't matter. Anyway, you're on the beach. It's a gorgeous day

out. It's sunny and warm. Like I said, you're watching these waves roll in. You can hear it. Maybe there's a seagull or two. You got a drink in your hand. The sun is beating down. It's just amazing. And because you're you, and this is my metaphor, you decide to run a little physics measurement.

You know, I'm the one in charge of this fantasy, all right?

So we're just going to go with it.

It's part of the deal.

You get to go on a beach vacation, but you have to do some physics experiments.

You decide you want to measure the wavelength of the waves.

Wave length, if you think of a wave, this roly upy-downy thing, and I'll describe waves in a little

bit more detail in a little bit, but generally waves are these upy-downy things, and the distance

between any two upy parts is the wavelength, or the distance between any two downy parts,

is the waves repeat themselves, and then the distance a wave has to go before it repeats

itself is the wavelength and you're going to measure the wavelength of these ocean waves

washing onto the shore. To do this you're going to stand right on the shore and you're going

to watch as the waves roll over you. So the water might start at ankle deep and then you'll watch it rise up to your thighs

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