# Lesson video

In progress...

Hi, everyone, it's Ms. Mitchell here.

I can't wait for our math lesson today.

Today, we're going to be identifying 2D shapes on the surfaces of 3D shapes.

In today's lesson we'll be looking at the properties of shapes, you will complete a talk task, an independent task, and then a quiz.

For today's lesson you will need a pencil and some paper.

Here we have a picture of a cube.

Now we know that a cube has six faces.

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

We know that a cube has 12 edges.

One, two, three, four, five, six, seven, eight, nine, 10, 11, 12.

And we also know that it has eight vertices.

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

Now, can you describe the cube without using the word edges, vertices or faces? So you can't use those words, but you need to tell me what a cube is.

You could say that the cube has six squares.

Now we know they're six squares because all the sides are the same.

For your talk task, I would like you to please match the sentence to the correct picture.

Make sure you say it out loud.

So let's do the first one together because we just did that.

The sentence says this shape has six square faces.

So you would say out loud, this card says this shape has six square faces so it matches the key.

Could you please pause the video to complete the other sentences? And here are the answers.

So we have already completed the square faces.

The next one says the base of this shape is a circle.

So this here we have the cone.

Now it could have been the cylinder because the cylinder has a circle base.

However, this sentence says the base and top of their shape are circles.

So that's how we knew this one matched the cylinder because the cone only has one circle at the base.

Whereas the cylinder has two circles at the base and at the top.

So this meant this shape has six rectangular faces.

This has two rectangular faces at the end.

And then one, two, three, four.

Well done.

This black shape here is the shadow of a 3D shape.

What shape or shapes might it belong to? How do you know? So is this shape here, the shadow of a cylinder, a cone, a cuboid or a cube? What do you think? So let's do a process of elimination.

So could this shadow here match the cylinder? No, it can't.

And it can't match it because the base and the top of a cylinder is a circle, there is no square in a cylinder.

So you know that this one, it cannot match.

The next shape here is a cone.

Could this shape here? Could this shadow here match the cone? No it can't.

And why not? It can't match the cone because you know the base of a cone again, is a circle, not a square.

The next shape we have is a cuboid.

Now could this shadow here match the shape of a cuboid? Yes, it can because these two ends of a cuboid could be a square or a rectangle.

So yes, it could match this cuboid here because the ends of a cuboid could be a square or a rectangle.

So yes, it could match this shape.

Could the shadow over here match the cube? Yes, it can.

And how do you know that? Because all the faces of cubes are square.

They are all the same.

So therefore this shadow could belong to a cuboid or a cube because they could both have a square face.

Great work.

What I'd like you to do for your independent task is to describe which 3D shape this shadow will belong to.

But more importantly, tell me why.

Tell me the reason why you think that.

Please don't just tell me the shape.

Tell me the reason.

Could any of them belong to more than one shape? And which ones? Pause the video now and then press play when you are ready for the answers.