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 are ready to work hard and have lots of fun.

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

This lesson is called Make different sized angles by rotating two lines around a fixed point.

It comes from the unit Right Angles.

By the end of this lesson, you will be able to create different sized angles by rotating lines around a fixed point.

If you haven't heard of angles or fixed points before, don't worry, this might be some new learning for you, but I will help you and we'll learn about it together.

There are five key words that are going to be really important in this lesson, so I would like you to practise saying them.

I'll have my turn first and then it will be your turn to say each word, ready? My turn, angle, your turn.

My turn, rotate, your turn.

My turn, fixed point, your turn.

My turn, clockwise, your turn.

My turn, anti-clockwise, your turn.

Well done, let's have a look at what some of those words mean.

An angle is a measure of turn.

It shows how far something has rotated.

You are going to be using strips of card, a bit like these, in this lesson to explore angles a little bit more.

Rotate means to turn around a fixed point.

It is an action or a movement.

A fixed point is a point that does not change or move.

That's why it's fixed, because it will stay in one place.

Clockwise is the direction that the hands of an analogue clock travel, like this.

So the hour hand, the minute hand, and the second hand all travel in a clockwise direction.

Anti-clockwise is the opposite direction to the hands on an analogue clock, like this.

To begin with, you are going to learn about turns in real life, and then in a little while, you are going to identify the key features of an angle.

There are two children who are going to help in this lesson, their names are Sofia and Jun.

Look out for them and listen carefully when they appear, because they have some really important information that can help you in this lesson.

Sofia and Jun are watching the hands on the clock.

Jun notices, at 11 o'clock, the hands are quite close together.

Sofia notices, at 10 past 11, the hands are further apart.

At half past 11, they are further apart again.

Sofia says, "I wonder why the hands are getting further apart." Do you know? I think Jun knows too.

The hands are rotating clockwise, the hands are turning around the clock.

The minute hand is rotated more than the hour hand, that's why the hands have got further apart.

Hands on an analogue clock always rotate clockwise, so the hand you can see spinning around now rotating, that is rotating in a clockwise direction, because it's the same direction the hands on a clock travel.

Jun wonders, could he try and rotate clockwise too? Maybe you could try this as well, do you think you would be able to rotate clockwise? Let's see if Jun can do it.

You can see him rotating clockwise, the same direction as the hands on a clock.

When something rotates the opposite way to the hands on an analogue clock, it is called an anti-clockwise turn.

So the hand you can see rotating now, that is in an anti-clockwise direction, the opposite way to the hands on a clock.

Do you think Jun can try and rotate anti-clockwise this time? Maybe you could try it with him.

Now you can see that Jun is turning in an anti-clockwise direction.

Let's check that you can recognise clockwise and anti-clockwise turns.

Who is rotating clockwise, is it A, B, or C? I'll give you a few seconds to watch them before you decide.

Who is rotating clockwise? Well done if you said B, it is B that is rotating clockwise.

Can you say which arrow shows an anti-clockwise turn? Do you think it's A, B, or C? You can pause the video if you need a bit more time.

The anti-clockwise turn is C, well done if you said C.

You can see turns in other places too, not just the clock.

Jun says, "I can rotate the tap clockwise to make it hotter, like this." Sofia says, "I can rotate the tap anti-clockwise, like this, to make it colder." Have you used a tap like this before where you have to turn the handle to change the temperature of the water? If you have, you've been making a clockwise or an anti-clockwise turn each time you change the temperature of your tap.

This car is making turns during its journey.

If you go out in the car, your car will be making turns too.

There is one more turn.

Let's see where else we might see turns.

The door turns when you open and close it.

What turns can you see when moving these objects? What turns would you see in the scissors, the glasses, and the watch? Pause the video and have a think.

The blades on the scissors turn when they cut.

The arms on the glasses turn when they fold in.

And the hands on the watch can turn.

Well done if you noticed those things that can turn too.

Have a look around you, can you see something that completes a turn? What can you see that could rotate clockwise or anti-clockwise? Pause the video and have a look around you, what can you see that can complete a turn? Here are some things that you might have seen.

Jun said, "I can see that the door handle rotates clockwise to open the door." And Sofia said, "I can see that the toilet flush lever rotates clockwise to flush the toilet." Wonder what other things you noticed.

Sofia and Jun are going to use some strips of card to practise making their own turns.

Carefully, they're going to use a split pin to join their strips of card together like this.

Sofia says that Jun's strips are close together, she's going to make hers further apart like this.

When you measure the amount of turn that something has made, you are measuring the angle.

So Jun has made a smaller angle, and Sofia has made a larger angle.

Jun has only turned his strip a small amount, and Sofia has turned her strip a larger amount.

Angles are made when something rotates around a fixed point.

Sofia and Jun have used a split pin to make a fixed point.

Jun says, "I rotated my strips a smaller amount around my fixed point." Sofia says, "I rotated my strip a larger amount around my fixed point." Sofia and Jun are trying to make small angles, so they will only rotate their strips a small amount.

Can you imagine what those are going to look like? Let's have a look at some.

All of these have only been rotated a small amount, so these are all small angles.

Now, Sofia and Jun want to make larger angles, so they need to rotate their strips a larger amount.

Let's see if they can do that.

Let's rotate the first one, a larger amount, and the second one has been rotated the larger amount.

And the third one, you could rotate both your strips to show a larger amount of turn.

Now they have made larger angles.

Let's check if you can find small and large angles.

Who has made the largest angle here? A, B, or C? The largest angle is B, well done if you said that.

Who has made the smallest angle here? A, B, or C? The smallest angle is B, well done if you said B.

Jun went back to looking at the clock, and he tried to make the angle that he could see on the clock with his strips, and he said, "I can rotate my strips to make the same angle that I can see on the clock." So let's see what he did.

He moved both his strips, and then he says, "I can place it over the clock to check that the angles are the same." So he is gonna place his strips over the clock, and we can see that Jun's angle strips and the hands on the clock are both showing the same angle.

They have both got the same amount of turn.

Later on, Sofia tried to make the angle on the clock.

Sofia can rotate her strips to try and match the angle of the hands on the clock.

She rotated them like this and then she placed her strip over the clock to check, and she can see that the angle of her strips and the angle of the hands on the clock are both the same.

Let's check if you can see who has made the same angle that you can see on the clock.

Do you think it's Jun or Sofia? The person who has made the same angle that you can see on the clock is Jun.

You can check by placing his angle strips over the clock, and we can see that they've both got the same amount of turn, the same angle.

If we place Sofia's, we can see that Sofia has turned too much, hasn't she? Her angle is larger than the angle shown on the clock.

I would like you to go and make your own set of angle strips now, so that you can be like Jun and Sofia and you can use them to make different angles.

You need two strips of card and you need to use a split pin to join them together.

Make sure that you are careful with the pin, because sometimes they can be sharp.

You're going to take your strips of card like this, push your pin through so that you've made a fixed point where you've joined your strips together.

Now you are going to use your angle strips to see if you can match them up to different angles around you.

You could look at the hands on a clock, you could look at the turn of the door, or a pair of scissors when you use them for cutting.

Sofia says, "As you turn your angle strips, say if you are turning them clockwise or anti-clockwise." Once you've done that, I would like you to use your angle strips to follow each instruction that you can see here.

So you're going to use your strips to turn a small amount, turn a large amount, turn halfway, turn all the way, make a small angle, and make a large angle.

After each instruction, compare your angle strips with your partners', do they look the same or do they look different? See if you can explain why.

Are you ready to go and try out having a look at some of these angles? Excellent, off you go.

Well done, let's have a look and see how you have got on.

First, you had to use your angle strips to match them to different angles that you could find around you.

There are so many different things that you might have tried.

Let's have a look at what Jun and Sofia did and see if yours was similar.

Jun matched the angle to a pair of scissors and he made a clockwise turn.

Sofia matched the angle to the tap, she made an anti-clockwise turn.

Did you remember to say if you were turning clockwise or anti-clockwise? Well done if you did.

Then you had to use your strips to follow these instructions.

The first instruction said, turn it a small amount, so it might have looked a little bit like this, but it doesn't have to look exactly the same.

You might have turned it a bit less or a bit more, and you also might have been holding it a different way round.

Maybe your pin was at the top and your strips were pointing down, that doesn't matter, as long as you only turned them a small amount.

The next instruction said, turn it a large amount, so you need to turn it further around than last time, like this.

Turn it halfway round.

Did you notice that that made a straight line? Then the next one said, turn it all the way round.

When you do that, it looks like you only have one strip of card, doesn't it? Because one is right on top of the other one.

If you turn it all the way round, this is what it should look like.

Make a small angle, we are looking for a small amount of turn, a bit like the first instruction.

And finally, make a large angle, we are looking for a larger amount of turn, so perhaps something like this.

Well done if you were able to follow those instructions and make all of those different angles with your angle strips.

Now it's time to move on to the second part of the lesson, and you are going to learn about the key features of an angle.

What does an angle have to have? Let's find out.

Jun and Sofia have made some different angle strips now, can you see how they look different? Jun has some longer strips, doesn't he? And Sofia has shorter strips.

Jun says, "I think that I've made a larger angle because my strips are longer." Let's check if Jun is correct.

Remember, an angle is a measure of how much something has turned.

If we place Sofia's angle strips on top of Jun's like this, we can see that they have turned the same amount.

The angle is the amount of turn around a fixed point, not the length of the line.

If they have turned the same amount of turn, that means that the angle is the same.

An angle is the amount of turn around a fixed point.

The lines could be longer or shorter, they could be wider or narrower like this, the important thing is how much has it turned? The length of the line does not affect the amount of turn.

If we place these two on top of each other, you can see that the amount of turn is the same, so these two angle strips show the same angle even though the lines are different.

Let's check if you understand that.

Have a look at this first angle, and now look at the second angle.

Can you complete this sentence? In the second angle, the lines are mm, and the angle is, mm.

You can use these words to help you, pause the video and have a think, how could you complete that sentence? Let's have a look, in the second angle, the lines are shorter and the angle is the same.

Well done if you spotted that.

Let's try another one.

Have a look at the first angle.

Now have a look at the second angle.

And now have a go at completing this sentence.

In the second angle, the lines are mm, and the angle is mm.

Here are the words to choose from, pause the video and have a go at completing that sentence.

This time, in the second angle, the lines are the same and the angle is smaller.

Well done if you completed that sentence correctly.

These strips of card look a bit different to the angle strips we saw before.

Can you see what's missing this time? Oh, Jun says, "I've lost my pin, can I still make an angle?" What do you think? Do you think that Jun can still make an angle if he's lost his pin? Let's see what Sofia says.

She says, No, an angle needs to rotate around a fixed point." The pin was the fixed point, wasn't it? So if you have no pin, you have no fixed point, and so you won't be able to make an angle.

Oh, this one looks a bit different too.

Sofia says, "My card is bent, can I still make an angle?" What do you think this time? Let's see what Jun says.

"No, the lines in an angle should be straight." So if the card has been bent like Sofia's, you'll need to make a new one, because you can't make an angle with lines that are bent, they need to be straight.

Let's check that you understand those points by having a go at a true or false quiz.

I'm going to show you five sentences, and I would like you to decide if each one is true or false, and then after you have seen all five, I will tell you which ones are true and which ones are false.

I'll give you a few seconds to answer each one, ready? True or false, angles need to have two straight lines? Remember, I will tell you the answers after we have done all five.

A smaller angle always has shorter lines.

An angle is a measure of length.

The length of the line does not affect the angle.

Angles rotate around a fixed point.

You were thinking really carefully about those, well done.

Let's have a look and see which ones are true and which ones are false.

A, angles need to have two straight lines, that is true.

B, a smaller angle always has shorter lines, that is false.

An angle is a measure of length, false.

The length of the line does not affect the angle, true.

Angles rotate around a fixed point, true.

Well done if you were able to say that those were true or false.

Now it's time for you to do a bit of practise.

I would like you first of all to look at the angles on the top row and the bottom row and see if you can match the ones that are the same.

If you would like to, you could use the angle strip that you've made to help you match them.

When you've done that, you're going to have a go at this second task.

Look carefully at what is drawn inside each box.

I would like you to tick the boxes that have an angle inside.

You need to think really carefully about the important things that an angle must have.

Then I would like you to explain to a partner why you didn't tick some of them.

Can you explain your reasons? How do you know that some of these are not angles? You can go and start that work now, off you go.

Well done everyone.

Let's have a look at how we can match these angles together.

The first angle is the same as the second one on the bottom row, and the second angle is the same as the first one on the bottom row.

The third angle is the same as the last one on the bottom row, and the last angle on the top is the same as the third angle on the bottom.

Did you look really carefully at the amount of turn that you could see? Well done if you did, that's really important when we are thinking about angles.

Let's have a look at the second task.

First, you needed to tick all the boxes that have an angle inside.

These are the boxes you should have ticked.

There is 1, 2, 3, 4.

Four of these boxes had an angle drawn inside.

The rest are not angles.

Did you manage to explain why these are not angles? Let's have a look and see if you said something similar.

First, let's focus on these ones, these all have curved lines, that's why they are not angles, remember, an angle needs to have two straight lines.

These ones have no fixed point, they're not joined together, there's a gap.

If they don't have a fixed point where they are joined together, it is not an angle.

Well done if you remembered both of those points and you were able to explain to a partner.

Now that you are at the end of the lesson, you have learned that an angle is a measure of turn.

You know that a turn can be clockwise or anti-clockwise, and you know that you can see turns all around you in lots of objects.

Things like a door, a clock, scissors, and glasses, and probably lots more that you can think of too.

You know that the length of the line does not affect the amount of turn, and you also know that an angle is made when two straight lines rotate around a fixed point.

You have thought so carefully about angles today and looked around you to find objects that can complete a turn.

You've thought about clockwise and anti-clockwise.

Well done everybody.

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