### Video Transcript

3D Shapes

In this video, we’re going to learn
how to identify some common 3D shapes. And we’re going to learn how to do
this regardless of their size, what color they are, and no matter what position we
put them in. In particular, we’re going to
concentrate on six different shapes. Let’s go through them one by one to
find out more.

This is a sphere. The first thing we can say about a
sphere is that it has a curved surface all around. And it’s this curved surface that
means a sphere can roll. Spheres are ball-shaped. This marble is a sphere, and so is
this beach ball. They may be different sizes, but
they’re both spheres. We know this because they have a
curved surface all around, and we can say that they’re ball-shaped.

How can we recognize a
cylinder? This is a cylinder. The first thing we can say is that
it has a curved surface. But if we look carefully, we can
see that this shape has got two flat surfaces too. They’re opposite each other, one at
each end of the cylinder. This tin of beans is a
cylinder.

We can see that it has a curved
surface all the way around, and the flat surface at each end means it’s perfect for
stacking in the supermarket. These objects may be different
colors, but we can see that they’re both the same 3D shape. They have curved surfaces and two
flat surfaces, one at each end. They’re cylinders.

This shape is a cone. Like a cylinder, it has a curved
surface too. It also has a flat surface, but
only at one end. And we can’t see this in the
picture of the cone that we’ve got. Let’s turn it around. There we go. Now, we can see the flat surface a
lot more clearly, but what’s at the other end of the cone? We can see a point. Cones have a flat surface at one
end and a point at the other.

This is a cone. We can see the curved surface, a
point on one end. And although there isn’t a flat
surface at the other end, we can see that there should be one. This sort of cone has been hollowed
out so that we can fill it with something delicious. It’s an ice cream cone!

So far, we’ve thought about three
shapes that have curved surfaces. Now, let’s identify some shapes
that only have flat surfaces. This is a pyramid. All of its surfaces are flat. It has a flat surface underneath or
on top, depends which way we look at our pyramid. Let’s just say it has a flat
surface at one end, but what’s at the other end? Just like a cone, there’s a point
at the other end.

The ancient Egyptians built huge
pyramids. So, we can identify pyramids by
noticing that all the surfaces are flat, and they have a flat surface at one end and
a point at the other.

Now, it’s helpful to compare our
last two shapes, so let’s look at them at the same time. First of all, the cube. This is a cube. Again, we can see that it has no
curved surfaces; they’re all flat. A dice is a cube, and thinking
about a dice is really helpful. We know that there must be six
surfaces to a cube because our dice goes up to six. Each surface has a different number
on it, but also each surface on a cube is the same shape.

We could turn our cube into
different positions. We could even decorate the surfaces
in different ways. But no matter how we look at our
cube, each of the six flat surfaces is exactly the same shape. That’s really important. And it’s really important because
our next shape, the rectangular prism, also has six flat surfaces.

But if we look carefully at our
rectangular prism, it looks a little bit like a cube that’s been stretched. And if we turn a rectangular prism,
it helps us to see that not all the surfaces are the same shape. Can you see how this surface here
on the end is a lot smaller and thinner than this surface with a white arrow on
it? A rectangular prism has six flat
surfaces, but they’re of different sizes.

A brick is a rectangular prism, as
are many other boxes that we buy when we do our groceries. Another word we may come across is
cuboid. Like we said, a rectangular prism
is a little bit like a stretched or a squashed cube.

Now that we’ve learned about
spheres, cylinders, cones, pyramids, cubes, and rectangular prisms, let’s have a go
at answering some questions where we have to identify these 3D shapes.

Choose another cube.

In this question, we’re shown a
picture of a 3D shape. It’s a cube. And we’re asked to choose another
cube. We need to choose from the three
possible 3D shapes at the bottom, but none of the shapes looks exactly like the cube
in the picture. They’re all different colors. They look like they’re different
sizes. Or maybe, the cube we’re looking
for is in a different position.

Let’s remind ourselves what we know
about cubes to help spot which of the shapes is a cube. One thing we know about cubes is
that all the surfaces on a cube are flat. There’s nothing curved about a cube
at all. But if we look at our first shape,
we can see that it does have a curved surface, goes all the way around. This shape can’t be a cube. It’s a cone.

The second shape also has a curved
surface. And again, we can see it goes all
the way around. This shape isn’t a cube either. We call this shape a cylinder. And so, we know the green shape is
a cube. All of its surfaces are flat. And although it’s a different size,
a different color, and in a different position to the cube in the picture, we know
that this makes no difference at all. It’s still a cube. The green shape is a cube.

Is this a sphere?

We can see a picture of a red 3D
shape here. And we need to find out whether
this shape is a sphere or not. To help us, let’s remind ourselves
what makes a sphere. Firstly, we know that spheres have
a curved surface all around. This shape has a curved surface all
around. Maybe it’s a sphere then.

Something else we know about
spheres, though, is that they’re ball-shaped. Does the red shape look like a
ball? Well, no. It looks like a ball that’s been
squashed. Although our red shape does have a
curved surface all around, it’s not ball-shaped. And so, we can say no, it’s not a
sphere.

How many cylinders are there?

In this problem, we’re shown eight
different 3D shapes, and we need to count the number of cylinders that there
are. But for us to be able to do this,
we need to remind ourselves what makes a cylinder. Firstly, we know that cylinders
have both curved and flat surfaces. These two shapes on the top row
don’t have any curved surfaces at all. Let’s cross them out. They’re not cylinders. And although this shape on the
bottom row does have a curved surface, it doesn’t have any flat surfaces. It’s a sphere.

So, we’re left with five possible
shapes. What do we know about the flat
surfaces on a cylinder? We know that cylinders have two
flat surfaces, one at each end. If we look carefully, we can see
that some of our shapes only have one flat surface. And at the opposite end, they have
a point. We know these shapes are cones.

And if we look at the two shapes we
have left, we can see that they do have two flat surfaces. One, two. There are only two shapes here that
have a curved surface and flat surfaces, one at each end. So, we can say there are two
cylinders.

Now, what have we learned in this
video? We’ve learned that it doesn’t
matter what size, color, or even what position a 3D shape is in. We’ve learned how to identify
different 3D shapes using what we know about their features.