Lesson video

Hello, everybody.

My name is Mrs. Johnson.

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

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

Let's see what we're going to be learning about today.

This lesson is called lines of symmetry.

It comes from the Unit: Shape.

Discuss and compare 2D and 3D shapes.

By the end of this lesson, you will be able to identify shapes and images that have reflective symmetry and explain where the line of symmetry lies.

Don't worry if you haven't heard of a line of symmetry before because this lesson will help you learn all about it.

I am here to help you and we will learn about it together.

There are three important keywords in this lesson that we are going to practise now.

I will say them first and then it will be your turn.

Ready? My turn, line of symmetry.

Your turn.

My turn, reflection.

Your turn.

My turn, symmetrical.

Your turn.

Well done.

Listen out for those words throughout this lesson because they are going to be really important to your learning today.

There are going to be two parts to this lesson.

To begin with, you are going to learn about finding a line of symmetry and then in a little while you are going to learn about drawing lines of symmetry and shapes.

Let's start with finding a line of symmetry.

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

Their names are Sofia and Jun.

Listen carefully to the things that Sofia and Jun have to tell you because they are really helpful for your learning today.

Sofia is making some cards for her family.

She has folded her piece of card in half and drawn a shape to cut out.

She's going to cut her shape out.

It looks like this.

And when she unfolds her shape, this is what it looks like.

She's made a heart shape card.

Here is another card Sofia made.

She drew the shape and then she cut it out and when she unfolded it, this time she'd made a star shape card.

Can you match Sofia's drawings to the cut-out cards? On the top you can see the drawings that Sofia made and at the bottom you can see the shape of the card that she made when she cut it out.

Which drawings and which cut-out cards go together? Pause the video and see you can match them up.

The first shape Sofia drew goes with this card.

The second shape goes with the first card and the last shape Sofia drew goes with the card in the middle.

When a shape can be folded in half and both sides are the same, the line where you folded is called the line of symmetry.

Sofia's cards all have a line of symmetry.

It's the line where Sofia had folded her card and both parts of the card will match up and be the same shape if Sofia folds on the line of symmetry, both sides would be the same.

Jun could use a line of symmetry to make a butterfly painting.

Here is the line of symmetry on the butterfly.

Jun says, "I will only paint on one half of the butterfly." So Jun is going to put his paint on this half, can see he has chosen to put blue and green at the top of his butterfly.

He has got orange in the middle and he has put purple, green and blue paint at the bottom of his butterfly.

He has painted on one half of the butterfly.

Now Jun says, "I can fold my butterfly following the line of symmetry and press it down." So he's going to fold his butterfly on the line of symmetry and press it down.

What do you think is going to happen to the paint? Shall we have a look? Jun says, "When I unfold it, the paint will be on both sides.

What do you think it will look like?" Let's have a look.

Here is Jun's butterfly now.

So we can see now there is paint on both sides and the pattern on one side matches the pattern on the other side, doesn't it? So if you look at the butterfly now, there is blue and green at the top on both sides.

There is an orange dot of paint near the body in the middle on both sides of the butterfly and at the bottom, both sides have purple, green and blue.

The pattern on one side is a reflection of the other side.

That means that when it is folded, the two halves will match so the blue dots at the top of the butterfly, when we fold that butterfly along the line of symmetry, the two blue dots will match up.

The two orange dots will match up, the two green dots at the top and the bottom will match up and they will be in the same place when the butterfly is folded.

When a shape or an image has a line of symmetry like Jun's butterfly, it can be described as symmetrical.

This butterfly is symmetrical.

Sofia's cards are symmetrical.

One half of the shape is a reflection of the other side.

When you fold along a line of symmetry, both halves match.

Let's check if you can see which of these lines are lines of symmetry.

Imagine if you folded along each line, would the two halves match? Pause the video and have a think.

Let's have a look.

The first one is not a line of symmetry.

The line has not been drawn in the middle of the shape, so it is not a line of symmetry.

The second one is a line of symmetry.

If we folded that shape on that line, both parts would match.

The third one is not a line of symmetry.

The line is not down the centre so the two halves would not match if we folded it there.

The fourth one is a line of symmetry.

Those two parts would match if we folded down that line.

The fifth one is a line of symmetry.

The last one is not a line of symmetry.

If we folded on that line, the two parts would not be a match.

They would not be the same shape.

Now, it is time for you to practise finding a line of symmetry.

First, I would like you to see if you can match the folded shapes at the top to the whole shapes at the bottom.

You could draw lines to show which ones you think are a match.

When you finish that, you are going to try and create your own symmetrical butterfly art like Jun.

"Remember that you only need to put paint on one side of your butterfly" and then you are going to fold along the line of symmetry so that the paint can be transferred onto the other side and make a symmetrical pattern.

If you don't have any paints, you could draw a symmetrical pattern instead.

When you have finished creating your symmetrical butterfly art, I would like you to see if you think each line is a line of symmetry, you need to tick or cross each shape to show if the line of symmetry is correct.

Are you ready to go and try that now? Excellent.

Off you go.

Well done.

Let's see how you have got on.

First, you need to match the folded shapes to the whole shapes.

It really helps if you can try and imagine holding a piece of card that would look like this and then imagine if you opened it up, what would the shape be? The first one would be a circle.

The second one would be a square.

The third one would be a rectangle and the fourth one would be an oval.

This is how you should have matched them up correctly.

On your second task, your butterfly might have looked something like this.

Have a look and see "When you fold your butterfly along the line of symmetry, do the two halves match? If they do, your butterfly is symmetrical." You got to this task.

You needed to think really carefully about whether each line is showing a line of symmetry correctly or not.

Let's see how you got on.

The first one is a correct line of symmetry.

If we folded along that line, both parts would match up and be the same.

The second one is a line of symmetry.

The third one is not a line of symmetry.

If you folded that shape, the two sides would not match up and be the same.

On the bottom row, this one is not a line of symmetry.

These two parts wouldn't match if you folded them.

The next one is a line of symmetry and the last one is not a line of symmetry because on the speech bubble, one side has a little extra bit, doesn't it? Sticking out at the bottom and the other side doesn't.

That means if you folded on the line of symmetry, the two parts wouldn't match up because they're not the same shape.

Well done if you were able to say which lines of symmetry were correctly drawn, it shows that your thinking really carefully about finding where the line of symmetry is.

Good job.

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

We are going to be thinking about drawing lines of symmetry and shapes.

Have a look at these shapes.

Do you think there would be a line of symmetry on these shapes or not? Let's have a look.

Jun says, "If I imagine folding these shapes in half, I think both halves would match." "That means that these shapes are symmetrical." If a shape is symmetrical, you can use a ruler to draw the line of symmetry.

That means you can draw a line to show where you would fold the shape to make both parts the same and make sure that they would match up.

You take your ruler and first Jun says, "You need to line up the ruler along the line where you imagined the fold." That's here, isn't it? "Then you need to hold the ruler still while you draw the line.

Keep the pencil against the ruler." So make sure that you hold the ruler still and you keep the pencil touching the ruler all the way down the line like this.

When you lift off your ruler and your pencil, you can see that you've drawn the line of symmetry.

"Let's draw the lines of symmetry on the other shapes." Line up the ruler where you would like the line of symmetry to be.

"Hold the ruler still.

Keep the pencil pressed against the ruler all the way down." There is our line of symmetry and the final shape will do the same thing.

Place the ruler where you would like your line of symmetry.

Hold it still.

Keep the pencil pressed along the ruler all the way down.

There is our line of symmetry.

Jun has drawn a line of symmetry on each shape.

How do you think he could improve his work? What could he do to make it a little bit better? Pause the video and have a think.

Here are some things you might have thought of.

On the first one, Jun could use a ruler to make sure that his line of symmetry is straight.

His line is a little bit wobbly, isn't it? Perhaps he didn't hold his ruler very still.

If he had another try and he holds his ruler really still and he keeps his pencil pressed against the ruler all the way down, his line could look like this instead and that would be a big improvement, wouldn't it? On the second shape, his line is really straight, but there's something that's gone a little bit wrong.

Did you notice Jun's line of symmetry should be exactly down the middle of the shape because of that's where the fold would be to make the two parts the same.

Jun needs to move his line or draw his line right down the middle of the shape like this.

That's how Jun could improve his work on the second shape.

Well done if you said that too.

Now, Jun and Sofia are going to play a game.

We can see they've got a grid with some squares on it and there is a line down the middle which says it's a line of symmetry.

Sofia is going to draw the reflection to finish drawing the symmetrical shape.

This is what Sofia would draw.

Jun and Sofia's game means that when they have finished, they have created a symmetrical shape.

If you folded on that line of symmetry, you can see that the part that Jun drew and the part that Sofia drew would match up, wouldn't they? They would be the same, so they have drawn a symmetrical shape.

Let's watch them play again.

This time Jun's going to draw a different shape next to the line of symmetry.

And Sofia is going to draw the reflection.

Here it is.

And now they have created another symmetrical shape.

Let's watch them again.

Jun is going to draw one half like this and Sofia is going to draw the reflection like this.

Ooh, something doesn't look quite right, does it? If you folded on that line of symmetry now, I don't think that the part that Jun has drawn and the part that Sofia has drawn would match up.

They're not quite the same, are they? Jun says, "The part that I drew was three squares across.

Yours is only one square across." Have a look at this.

Jun's part is 1, 2, 3 squares along.

Sofia's part is only 1.

They're not the same.

Sofia says, "I will draw it again so that the shape we have made is symmetrical." Sofia is going to have another go so that the line of symmetry is in the correct place to create a symmetrical shape on this grid.

This time Sofia's going to draw it here and she can check by counting the squares, 1, 2, 3.

Now Sofia's part is three squares across and Jun's part is three squares across.

That means that now they have created a symmetrical shape.

Sofia and Jun played the game two more times.

We can see them here.

Did they create symmetrical shapes each time they played? How do you know? Look really carefully at the first game and the second game.

Have they created symmetrical shapes? Pause the video and have a little think.

They did create a symmetrical shape.

This is symmetrical because if you folded it on the line of symmetry, both parts would match, both sides are the same.

On the second game, this is not symmetrical.

If you folded this shape, the two parts wouldn't match because one part is bigger than the other.

We can check by looking at how many squares.

On Jun's side, it's 1, 2, 3 squares.

On Sofia's side, it's 1, 2, 3, 4, 5 squares.

Sofia would need to draw hers again and make sure that she only draws three squares along the bottom so that her drawing is the same size as Jun's drawing and then they would create a symmetrical shape.

Now, it's time for you to practise drawing some lines of symmetry and shapes.

I would like you to use a ruler to draw a line of symmetry on each of these shapes.

Sofia says, "Remember to use a ruler, hold it still and keep your pencil against it while you are drawing your line." When you have finished that, you are going to have a go at drawing the other parts of these shapes to make them symmetrical.

You will be drawing the reflection.

There are four different shapes for you to try.

Jun says, "Remember that each part should be the same size.

Counting the squares could help." If you notice that the parts that you are looking at is two squares across, you need to make sure that you draw your parts two squares across so that it is the same.

When you finish, you can use this space to design your own symmetrical shape.

Make sure you have a pencil and a rule already.

Off you go.

Well done.

Let's see how you have got on.

You should have drawn your lines of symmetry like this.

We want them to be a straight line down the middle of the shape, making sure that it goes all the way from the top to the bottom.

Imagine if you folded your shape on that line, would both parts match? If both parts would match, you have drawn your line of symmetry in the correct place.

Sofia says, "Did you try hard to hold your ruler still and draw a straight line?" Well done if you did.

It's quite tricky to use a ruler to draw a straight line, but it's really good to keep practising.

I think you've done a good job with that.

Let's see how you got on with drawing the reflections.

This is how you should have completed each symmetrical shape.

Here is the first one.

It ends up looking like a square.

The second one finishes with a rectangle.

The next one gives you a triangle, and the fourth one, perhaps you might have found this one, the most difficult should have looked like this.

The finished shape is a pentagon because it has five sides.

If you folded this shape on the line of symmetry, you can see that the two parts would match, so you have created a symmetrical shape.

"Did you remember to count the squares to help you make sure that both the sides were the same?" Well done if you did.

In this space, you might have drawn your own symmetrical shape a bit like this.

I drew this side first and then I drew the reflection afterwards.

I wonder if you were able to try and draw some different shapes that were symmetrical too.

Well done for thinking so carefully about how you might be able to do that.

Now that we are at the end of the lesson, you know that when a shape can be folded in half and both sides are the same, the line where you folded is called the line of symmetry.

One side is a reflection of the other side.

That means that when it is folded, the two halves will match.

When a shape or an image has a line of symmetry, we can say that it is symmetrical.

You have found lines of symmetry in different shapes and in patterns, and you have even created some symmetrical artwork of your own.

Well done for thinking so carefully about lines of symmetry today and for all your really hard work.

I hope that I will see you again soon for some more maths learning.

Bye, everyone.