(upbeat music) - Hey, everybody.

Welcome back.

Today, we've got a lot of work going on.

We are talking about three-dimensional shapes.

We've got some sand.

We're working on making some shapes.

I've got some helpers, Chloe and Harper, here with me here today and I'll tell you what, this is going to be some exciting stuff.

In fact, let's just dive into these three-dimensional shapes.

You may be more familiar with two-dimensional shapes.

These are those flat shapes like circles, squares, rectangles, but, today, we're going to look at adding another dimension, things like this shape here, and, Chloe, I think you kind of had one earlier that looked like this.

Do you know what shape this is?

- A rectangular prism.

- It's a rectangular prism, and what you're going to notice about these is that, if I look at just one side of it, it does look like a rectangle, but because it's a three-dimensional shape and not just a flat shape, there's more to it.

So, these flat sides, we call faces, and I can count all of those and I can say, okay, there's one, there's two, three, four, and then on the sides, there's more faces, five and six.

So this one has six faces.

Now, it also has other parts to it that we want to talk about, and those are the edges and vertices.

Now, the edges are those lines that go across.

So we have an edge here.

You can see another one.

Each one of these little rectangles are made up by these edges, and as we count 'em all, we can say one, two, three, four right here, but, remember, we have other parts to it.

So we've already counted that one.

That would be five, six, seven, and we could keep going, and there's more here.

We've got those on the edge here, and so all of those lines, those individual ones are called the edges of this shape.

Now, there's also, another word that I threw out there was vertices.

Now, vertices is like a corner, so it's where those edges come to a point.

So you can see right here on my rectangular prism, one, two, three, four vertices, where they come together right there, but then I have more on the other side.

Five, six, seven, and eight vertices on my rectangular prism.

That was a lot just for one shape.

Let's go ahead and look at another one.

Harper, it looks like you had one and it looks like it's falling apart.

The sand is falling, but it was kind of like this shape, wasn't it?

Do you know what this shape is called?

- A cube.

- It's a cube.

Now, what you're going to notice about cubes is that cubes are made up of squares on every face, those flat sides.

So we can see one, two, three, four, five, six faces to the cube, but all the sides are squares.

That's what makes this different from just a rectangular prism.

I'm talking about cubes.

Now, there's one more I want to get to, and, Chloe, you kind of have one that looks like it.

It looks like kind of an ancient structure.

What would this one be called, Chloe?

What do you think?

- A pyramid.

- A pyramid, and this is a square-based pyramid, because, on the bottom, you're going to see that this is a square, it's a perfect square, but then these sides, which are made up of triangles, go to a point at the top, and so this is our square-based pyramid.

There's a lot to learn about three-dimensional shapes, and we're going to keep building, keep playing, and I hope you do too.

Thank you so much for joining us today.

(upbeat music)