Teacher Talks: Video playlist

[THEME MUSIC]
[SCHOOL BELL RINGS]

Hello, I’m Mr Firth.

And today we’re going to learn all about 3D films.

Oh… sorry. I meant 3D shapes.

I’ll save these for another time.

So, what is a 3D shape?

3D is another way of saying three-dimensional. And three-dimensional means we can pick up the shapes because they have a length, height, and width.

All shapes are made up of either flat surfaces, curved surfaces, or a mixture of both.

We see loads of 3D shapes all around us.

Here’s one. A cereal box.

Let’s see what makes this shape 3D. Watch this.

Here is my cornflake packet. Let’s put lines on the edges of the shape.

Yes, I think that’s all the edges I can see.

Let’s slide the cereal box so we are left with the dark lines.

What do you see? Not just our cereal box, but also what the cereal box would look like without any writing or pictures on it.

Now it looks just like a shape you’d find in your maths books doesn’t it?

Recognise this shape?

That’s right. It’s a cube.

How can we describe this shape? Let’s start with the faces.

Does it have flat or curved faces? A cube has flat faces.

As you can see all the faces our square-shaped and they’re also all the same size.

Now we need to count how many flat faces this cube has.

Count with me.

One, two, three, four, five, six.

It has six square faces. Where the faces meet here, it’s called an edge. This cube has 12 edges.

One, two, three, four, five, six, seven, eight, nine, ten, 11, 12.

The edges are all the same length. And the corners have a special name too. They are called vertices. This cube has eight vertices.

One, two, three, four, five, six, seven, eight.

Did you notice how similar the cube is of a cereal box shape?

Let’s take a closer look at both shapes.

On the top we have a cuboid. And the shape below is a cube.

What’s the same and what’s different about them?

They both have six faces, 12 edges, and eight vertices but the cube has six square faces.

And the cuboid has six rectangular faces which differ in size.

So, they share loads in common. But are also two very different 3D shapes

Remember, all shapes are made up of either flat or curved surfaces, or maybe a mixture of both.

For example, this shape is called a sphere.

Is it a flat or a curved face?

Yes, it’s a curved face.

This shape only has one face.

There aren’t any edges or vertices.

One curved face allows this shape to roll.

I have just one more shape to show you today and it’s probably the trickiest one.

It’s this. Do you know what shape this is called?

It’s a prism. It’s a triangular prism to be precise because it has two triangular faces on either end.

Can you see that there are two different shapes?

This prism has two triangular faces. And three rectangular faces.

Let’s do some counting.

How many faces does a prism have?

One, two, three, four, five.

How many edges?

One, two, three, four, five, six, seven, eight, nine.

How many vertices?

One, two, three, four, five, six.

Well done, guys.

Let’s see how many three-dimensional shape names you can remember from today.

Can you name the shapes?

Let’s start with the orange shape.

The orange shape is a sphere. Did you get it right?

What about the blue shape? What is that called?

That’s right. It’s a cube.

What’s this yellow shape called?

That’s right. It’s a cuboid.

What’s this purple shape called?

Great work! A prism.

Well done. You’re three-dimensional geniuses

There are lots of three-dimensional shapes to be found at home.

Why not take a look and see if you can find any.

Happy 3D hunting, everybody.