Lesson video

Hello everybody, my name is Mrs. Johnson.

I am so happy to be here today to help you with some of your maths learning.

I hope you are ready to work hard and have lots of fun.

Let's have a look at what we're going to be learning about today.

This lesson is called Find Different Ways to Sort 3D Shapes.

It comes from the unit Shape, Discuss and Compare 2D and 3D Shapes.

By the end of this lesson, you will be able to find different ways to sort 3D shapes.

I wonder what you can remember about 3D shapes.

Do you know the names of any 3D shapes? Can you remember any of their properties? Can you remember the things that you can count on a 3D shape to be able to describe it? Don't worry if you can't remember those things because I am here to help you and we'll learn all about it to together.

There are three key words that we are going to practise to get you ready for this lesson.

I'm going to say each word first and then it will be your turn.

Ready? My turn, faces your turn.

My turn, edges, your turn.

My turn, vertices, your turn.

Make sure you listen out for those words today, you are going to be using them lots of times to help you with your learning in this lesson.

There are going to be two parts to this lesson.

To begin with, you are going to learn how to follow the sorting rule and then in a little while you are going to learn how to find the sorting rule.

Let's start by learning about how to follow the sorting rule.

There are going to be two friends in this lesson who help you today.

Their names are Alex and Jacob.

Look out for Alex and Jacob in this lesson because they are going to have lots of helpful things to share with you.

You can sort things into sets by making a rule.

If you have a look at these objects here, they are going to be sorted into two sets and the rule for the sets is has no eyes and has eyes.

Let's watch how each object gets sorted into one of these sets.

The penguin has eyes.

The lollipop has no eyes.

The conquer has no eyes.

The cheese has no eyes.

The rabbit has eyes.

The panda has eyes, the leaf has no eyes and the bird has eyes.

You can look carefully at what each object has or doesn't have to be able to sort it into the correct set.

Let's check if you can sort objects into sets.

For this one, these are your rules for the sets.

Has wheels, has no wheels.

I'm going to show you an object and you are going to say which set it belongs in, ready? A chicken? Well done has no wheels is correct.

A bus? Has wheels.

A car? Has wheels it goes with the bus.

A house? Has no wheels, that's right.

A bike? Has wheels.

A sandwich? Has no wheels.

A car? Has wheels, that's right.

Well done if you were able to sort each object into the correct set.

Now we're going to start thinking about 3D shapes and sorting into sets.

Alex says, I think I could sort these 3D shapes into sets.

Look at the rule that he's chosen.

Has a curved surface, has no curved surface.

Do you think you would be able to sort these shapes into these sets too? Let's watch Alex and you can see if you think that you would do it the same way as him.

Let's have a look.

He says the sphere has a curved surface.

The cuboid has no curved surface.

The cube has no curved surface.

The cylinder has a curved surface.

The square based pyramid has no curved surface.

The triangular prism has no curved surface, and the cone has a curved surface.

He was right, he can sort them into sets.

Now Alex is thinking, how else could I sort these shapes? He wants to think of a different sorting rule.

You could think about the properties of the 3D shapes.

Maybe you can sort 3D shapes by looking at the shape of the faces.

Alex is going to sort these 3D shapes into sets based on the shape of the faces.

Alex says, first I need to read the rule for each set and his rule is, has a circular face, has no circular face.

Alex needs to think about what that rule means.

He says, I know that a circular face is a flat circle shape within a 3D shape.

So he knows what he's looking for.

He's going to start with the first shape.

He needs to look carefully to see if it has a circular face and you can see that the cuboid does not have a circular face, so he's put it in the has no circular face set.

Now Alex says, I will look at the other shapes one at a time and sort them into sets.

Let's see if he can get all of these shapes into the correct set.

The cube has no circular face.

The cylinder does have a circular face.

The square base pyramid does not have a circular face.

The cone does have a circular face.

The triangular prism has no circular face.

The sphere has no circular face.

It has a curved surface.

Remember, that a sphere has no faces because it has no flat part.

It is a curved surface, not a circular face.

Let's check if you know how to sort 3D shapes into sets.

Alex has been sorting some shapes into sets, but he has one shape left.

Could you help him to put the cone into the right set? Pause the video and have a go.

Good thinking.

Did you remember to check what Alex's rules were for his sorting sets before you chose which set to put it in? His rule is has a triangular face, has no triangular face, A cone has no triangular face, so that is the set that it belongs in.

Well done if that's where you put the cone.

Now let's check if you are able to spot mistakes.

Jacob has tried to sort his shapes into sets by looking at the shape of the faces, but he has made a mistake.

Can you help him correct it? Look carefully at his sorting rule and look at where he's placed his shapes.

Can you find the mistake? Pause the video and have a go.

Jacob has put this shape in the has no square face set, but this shape does have a square face, so it needs to move into the other set with the cube.

Both those shapes have a square face.

Now Alex is thinking, how else could I sort these shapes? He doesn't want to think about the shape of the faces anymore.

He wonders if there is a different way that he could sort these shapes.

You could think about the properties of 3D shapes.

You know that 3D shapes have faces, vertices, and edges.

You could sort the 3D shapes by looking at the number of faces, the number of vertices, or the number of edges that a shape has.

Alex is going to sort these 3D shapes into sets based on the number of faces.

First, he needs to look at the sorting rule.

He needs to read the rule carefully for each set, five or more faces, fewer than five faces.

Alex can remember that a face is a flat surface on a 3D shape, so that's good.

He understands what a face is, so he understands the sorting rule.

He's going to start with the first shape.

He needs to imagine rotating the shape to make sure that he counts all the faces.

You know when you look at a picture of a 3D shape, you can't see all of its faces, can you? Some of them might be behind or underneath and you need to imagine picking the shape up and rotating it.

If you have any 3D shapes near you, perhaps you could go and get them and then you could hold the shape and rotate it so that you could count the faces.

A cuboid has six faces, so Alex is going to put it in the five or more faces set.

Now he's going to look at the other shapes one at a time and sort them into sets.

A cube has six faces, so it belongs in the five or more faces set.

A cylinder only has two faces, that's fewer than five.

A square base pyramid has five faces, so it belongs in the five or more faces set.

A cone only has one face, that's fewer than five.

A triangular prism has five faces, it belongs in the five or more faces set and a sphere has no faces, so that is fewer than five.

That's how Alex would be able to sort his 3D shapes by following this sorting rule.

Now, Jacob is going to sort the 3D shapes based on the number of vertices.

Jacob isn't thinking about faces, he is thinking about vertices.

First, he needs to read the rule for each set, six or more vertices, fewer than six vertices.

He needs to make sure he understands the rule.

Jacob can remember that a vertex is a corner on a 3D shape, so he knows if he's counting the vertices, he's counting the corners.

That's good.

He knows what that means.

He's going to start with the first shape.

Jacob says, I need to imagine rotating the shape so I can count all the vertices.

Just like when you count the faces, if you are looking at a picture, it's quite tricky to count them all because you can't see all of them, so again, if you have some 3D shapes, you could use those to help you or try to visualise.

That means try to make a picture in your mind of you picking up the shape and turning it around so that you can count all of the vertices.

The cuboid has eight vertices.

There are four at one end and four at the other end, so that is six or more.

Now, Jacob is going to look at the other shapes one at a time to decide which set they belong in.

The cube has eight vertices, the same as the cuboid.

Remember, a cube is a special type of cuboid, so they both have eight vertices.

It belongs in the six or more vertices set.

A cylinder has no vertices, that's fewer than six.

A square based pyramid has five vertices that's fewer than six.

A cone has one vertex that's fewer than six.

The triangular prism has six vertices, that belongs in the six or more set and a sphere has no vertices, so that belongs in the fewer than six vertices set.

Now, Alex is going to sort these 3D shapes into sets based on the number of edges.

First, he needs to read the sorting rule.

Fewer than eight edges, eight or more edges.

He needs to check he understands the rule.

He says, I know that an edge is a straight line where two faces meet.

That's good.

He understands what an edge is.

He's going to start with the first shape.

He needs to count all of the edges, so again, he needs to imagine that he's rotating the shape so that he can count all of those edges.

The cuboid has 12 edges, which is eight or more, so it belongs in the eight or more edges set.

Now, he's going to do the rest of the shapes one at a time and look really carefully to see how many edges they have.

The cube also has 12 edges, so it belongs in the eight or more edges set.

A cylinder has no edges, that's fewer than eight.

A square base pyramid has eight edges, so that belongs in the eight or more edges set.

A cone has no edges, that's fewer than eight.

A triangular prism has nine edges, so that belongs in the eight or more edges set.

And a sphere has no edges, that's going to join the cylinder and the cone in the fewer than eight edges set.

Now that you've seen Alex and Jacob sort their shapes based on edges, vertices, and faces, let's see if you can have a go at that.

Alex has sorted some different shapes into sets.

He has one shape left to sort.

Can you help him put the pentagonal pyramid into the correct set? Remember to look carefully at the rules and then decide which set that shape belongs in.

Pause the video and have a go now.

Let's have a look.

Alex's sorting rule was fewer than seven faces, seven or more faces, so you need to look at this pyramid and find out how many faces it has.

I can see that there is one face on the bottom, which is a pentagon.

That means that there will be five triangular faces, so if there are five triangular faces and one pentagon, five plus one is equal to six, so this pyramid has six faces, that is fewer than seven, so that is the set that it belongs in.

Fewer than seven faces.

Well done if you were able to choose the correct set for that pyramid.

Now, let's check if you can spot the mistake.

Jacob has tried to sort his shapes by counting the edges, but he got something wrong.

One of these shapes is not in the right set.

Can you help him find it? Let's look carefully at the rule before you have a go.

Jacob's sorting rule was odd number of edges, even number of edges, so you need to count the edges and decide if it's an odd number or an even number.

Pause the video and see if you can find which shape is in the wrong set.

Well done for thinking carefully about that one.

You needed to do a lot of checking and a lot of counting, didn't you to look at these edges.

The shape that you might have noticed in the wrong place is this one here, this cube.

You might remember that a cube has 12 edges.

It has four on the top, four on the bottom, and four around the middle.

12 is an even number, so the cube should have been in the even number of edges set.

Well done if you spotted that.

Now it's time for you to practise following the sorting rule.

First, you are going to choose what you would like your sorting rule to be.

You can use some of the words in the box to help you.

Once you've chosen your sorting rule, you are going to sort the shapes into the correct set.

You can use your own 3D shapes or you can use the cards that come with this lesson.

I wonder how many different ways will you be able to sort the shapes? How many different sorting rules do you think you will be able to try? Pause the video and have a go at that now.

Excellent sorting.

Let's have a look and see how you got on.

There are lots and lots of different ways that you could have chosen to sort your shapes.

I will show you a few different ones.

You could have sorted them like this, fewer than eight faces, which would include all of these shapes here.

Eight or more faces that would include these shapes.

Maybe you chose a different sorting rule.

Maybe you chose to look at vertices.

Fewer than eight vertices would have all of these shapes in that set.

Eight or more vertices would include all of these shapes.

I wonder what you chose to sort your shapes by.

Did you look at faces, or vertices, or edges? Maybe you did all three because you chose lots of different sorting rules.

Well done for thinking really carefully about how you could sort these 3D shapes into sets by looking carefully at their properties.

Good work.

Now it's time for the second part of this lesson.

Now that you've learned about following the sorting rule, you are going to find out how to find the sorting rule.

Let's have a look at that now.

Alex is going to sort these 3D shapes into sets by looking at the shape of the faces, but this time Alex is not going to tell you his rule.

He wants you to try and think about what his rule might be.

Let's watch carefully.

How is Alex going to sort his shapes? He's going to place them into sets.

Alex knows his rule, but we don't know Alex's rule yet, do we? If you look carefully at the shapes in each set, you can work out the rule.

You know Alex told you he was looking at the shape of the faces.

Let's think about the shapes in the first set.

Look at the shape of the faces.

Are there any faces that they all have that are the same shape? Then look at the 3D shapes in the second set.

Do you notice that there are any faces that are not the same shape that the 3D shapes in the first set do have? Hmm, I wonder what it could be.

Let's have a look.

Alex's rule was, has a triangular face, has no triangular face.

Look at the shapes Alex put in the first set, they all have a triangular face, don't they? All the shapes in the second set do not have a triangular face.

That was Alex's sorting rule.

When you look carefully at the shapes in each set, you can work out what his sorting rule was.

Now Jacob is going to sort these 3D shapes into sets by looking at the vertices.

Again, Jacob's not going to tell us his rule.

We have got to try and work it out, so let's watch how Jacob sorts these sets.

He is looking at the vertices.

Let's see where the rest of these go.

Okay, Jacob has finished sorting his shapes.

He's looked at the vertices.

I wonder what could the rule be this time? Do you notice anything about the number of vertices in the first set compared to the second set? I am thinking that Jacob's rule must be something to do with having four or less and five or more vertices because the triangular based pyramid has four vertices and that's in the first set.

The square based pyramid has five vertices and that belongs in the second set.

Let's have a look.

Jacob's rule four or fewer vertices more than four vertices.

It was to do with number four, wasn't it? We could find the rule by looking carefully at which shapes belong in each set.

Let's check if you can find the sorting rule.

This time, Jacob has sorted his shapes by counting the edges.

What could his sorting rule be? You are going to pause the video and have a think about what Jacob's sorting rule could be this time.

Okay, let's have a look.

Now, you might have found that it's really helpful to start by counting the edges of each shape.

If you did that, you would find that in the first set, the first shape has six edges.

The second shape has nine edges, and the third shape has eight edges.

In the second set, the shapes have 18, 12, and 15 edges.

Did you notice that the shapes in the second set have a greater number of edges than the shapes in the first set? Now that you know how many edges are on each shape, you can decide what the sorting rule might be.

It could be that Jacob's sorting rule was nine or fewer edges and more than nine edges.

It could be that Jacob's sorting rule was fewer than 10 edges, 10 or more edges.

There are quite a few different answers for this.

The most important thing was that you thought about how many edges each shape had to be able to work out what the sorting rule might be.

Alex sorted these 3D shapes into sets, this time Alex is not going to tell you what he looked at.

He might have looked at the faces, he might have looked at the vertices, and he might have looked at the edges.

You need to try and work out Alex's rule.

That means that you need to look really carefully at the shapes in each set.

If Alex chose to look at the faces, what could the rule be? Let's look at faces first.

You can see that the shapes in the first set have six faces on the cuboid, six faces on the cube, five faces on the triangular prism, so five and six.

The shapes in the second set definitely have more than five faces, don't they? So perhaps his sorting rule was six or fewer faces, more than six faces.

He could word that a different way.

He could say, fewer than seven faces, seven or more faces.

Maybe Alex's rule wasn't about faces.

Maybe it was about vertices.

If Alex's rule was about vertices, then maybe this could be his sorting rule, eight or fewer vertices, more than eight vertices, or he could phrase that a different way.

He could say fewer than nine vertices, nine or more vertices.

Maybe Alex didn't look at faces or vertices, maybe Alex chose edges.

If Alex chose to look at edges, then his sorting rule could be 12 or fewer edges, more than 12 edges, or it could be fewer than 13 edges, 13 or more edges.

You can see how it is really important to look at the properties of the shapes in each set so that you can decide what the sorting rule might be.

Let's check if you can decide what the sorting rule should be for these sets.

Jacob thinks that the sorting rule is eight or fewer edges and more than eight edges.

Alex thinks the sorting rule is eight or fewer vertices and more than eight vertices.

Have a really close look at the shapes in each set and see if you can decide who has chosen the right sorting rule for these sets.

Do you think it's Jacob or Alex? Pause the video and have a go now.

Well done for thinking carefully about that.

If we did choose Alex's rule, have a look at these three shapes here.

Would these shapes be in the right set if we chose Alex's sorting rule, eight or fewer vertices and more than eight vertices? We know that a cuboid and a cube have eight vertices, don't we? So if we chose Alex's sorting rule, all of these shapes would belong in the eight or fewer vertices.

That means Alex's sorting rule can't be correct.

The correct sorting rule was Jacobs, eight or fewer edges and more than eight edges.

Now, it's time for you to do a little bit more practise.

This time, you are going to have a look at the shapes that have already been sorted into sets, and you need to choose a sorting rule for each set that will be correct for the shapes that are already in there.

Again, you can use the words in the box to help you to write to your rule.

Once you've decided on your sorting rule, then you need to find more shapes that belong in each set.

You can use your own real 3D shapes that you might have, or you can use the pictures on the cards from earlier on in this lesson.

See if you can find more than one sorting rule.

Perhaps you could choose to look at the faces, and then the vertices, and then the edges and see how many different sorting rules you can think of for these shapes.

Pause the video and have a go at that now.

Let's have a look.

It's really helpful to start by counting how many faces, and vertices, and edges each shape has.

So the triangular prism has five faces, six vertices, and nine edges.

The square base pyramid has five faces, five vertices, and eight edges.

In the other set, the first shape has eight faces, six vertices and 12 edges, and the second shape has eight faces, 12 vertices, and 18 edges.

Once you know the properties of each shape, then you can choose a sorting rule.

You can choose if you want your rule to be about faces, or vertices, or edges.

If you chose faces, you could have this rule, fewer than six faces, six or more faces.

You could choose vertices.

Maybe you could have the rule fewer than eight vertices, eight or more vertices.

You might choose edges.

You could have fewer than 10 edges, 10 or more edges.

Once you've chosen your sorting rule, then you can find more shapes that belong in each set.

If you chose this sorting rule, fewer than 10 edges, 10 or more edges, these are the shapes that you could have in the first set because these all have fewer than 10 edges, and these are some of the shapes that you could have in the second set because these all have 10 or more edges.

Well done if you were able to find different sorting rules for these sets, and if you could find more shapes that belong in each set.

Now that you're at the end of the lesson, you know that you can sort 3D shapes by looking carefully at their properties.

You can sort by the shape of the faces, you can sort by the number of faces, or the number of vertices, or the number of edges.

You have also learned that you can look carefully at how shapes have been sorted to be able to find the sorting rule.

You have thought really carefully in this lesson.

Done lots of really good thinking about the properties of 3D shapes.

Well done.

I hope that I'm going to see you again soon for some more maths learning, bye.