Lesson video

Hi there, welcome to today's lesson.

My name is Mr. Peters, and in this lesson today, we're gonna be reviewing our understanding of what an angle is and how we can describe it as a measure of turn.

If you're ready to get started, let's get going.

So by the end of this lesson today, you should be able to say that I can recall understanding of angles as a measure of turn.

We've got a couple of key words we're gonna be referring to throughout in this lesson.

I'll have a go at saying them first, and then you can repeat them after me.

Are you ready? The first word is angle.

Your turn.

The second word is rotate.

Your turn.

The third word is clockwise.

Your turn.

And the last one, anti-clockwise.

Your turn.

Let's remind ourselves what these words mean.

An angle is a measure of turn.

It shows how fast something has rotated.

It is often displayed as the rotation between two line segments.

To rotate means to turn something around a fixed point.

It is an action or a movement.

Clockwise is the direction that the hands on an analogue clock take when they move around.

And anti-clockwise is the opposite direction that the hands on a clock travel when they move around.

Our lesson today is broken down to two cycles.

The first cycle is about creating angles and the second cycle is about types of term.

If you're ready, let's get started.

Throughout this lesson today, we're gonna be joined by both Jun and Laura.

They, as always, will share their thinking and any questions that they have throughout the lesson about our learning.

So our lesson begins with both Jun and Laura discussing the planets in our solar system.

Jun has a fact to share.

He says, "Do you know that every planet in our solar system rotates anti-clockwise except for Venus, which actually rotates clockwise?" Laura says, "What do you mean?" Well, let's have a look in a little bit more detail.

Jun says that every planet has an invisible axis that it spins around.

Here we go.

We can see these lines represent the axis, and then the planets rotate around these axes.

Let's take a look at Jupiter here.

This is the view of the planet from side on.

However, if we were to look at the planet from the bottom of its axis, here, it would look a little bit like this.

You can see that the black dot is representing the axis, and now we can see what the planet would look like from the bottom of the axis.

Now that we are looking at the planet from the bottom of the axis, we can see which direction the planet is rotating in.

It helps us to see more easily which direction the planet is rotating in.

Here we go.

Did you see that this planet here was rotating to the left, wasn't it? It was going anti-clockwise.

We can see that in more detail here.

Jupiter and all of the other planets rotate in this direction, they all rotate anti-clockwise.

And you can see that here linking that to the clock.

Here, the hands on the clock are rotating anti-clockwise.

This is not the normal way that the hands on the clock would rotate when we read the time.

However, when something rotates in the opposite direction, rotating round to the right, we can say that it is rotating in a clockwise fashion.

Here is Venus, and Venus is the only planet that rotates in a clockwise direction.

Again, we can relate that back to the clock here and we can see that this is the normal way in which the hands on the clock would rotate around when we're reading the time.

Jun is saying that it takes Venus 243 Earth days for it to spin on its axis in one complete rotation.

Hmm, and I have a great question, Laura, "I wonder how much Venus turns in one day." Well, we know that when we're measuring the amount of turn, we're actually measuring an angle, aren't we? Have a look here at Venus.

We know that where two lines meet, we create a fixed point.

So let's draw one line on here and look carefully at the lightly-colored crescent shape on Venus.

Let's see how it rotates round now.

And we can see now where that shape has now moved to.

So we can draw a second line now to identify the amount of turn that has taken place for Venus.

We know we have now just created an angle at a fixed point.

We know that we can also move these lines around this fixed point to make smaller or larger angles.

We can see here that the amount of turn is larger, so the angle would be larger.

And here, we can see that the amount of turn would be smaller, so the angle is smaller.

Some of the pupils in class have a go at drawing some of their own angles.

Which of these show an angle? Take a moment for yourself to have a think.

Laura's saying that she thinks these two do because they have the same length lines that meet with one level, don't they? Hmm, but she's not so sure on these two here.

They are straight lines that meet, but the length of these lines are slightly different, aren't they? Yep and that's right, Jun.

The length of the lines don't matter, do they? As long as the lines are straight at the point that they meet, it does not matter how long each one of the lines are when they create an angle.

Have a look at this example here again then.

Laura's fairly sure that this isn't an angle as it just looks like one curvy line.

And she's also saying here that these two don't have straight lines where they meet, so these also aren't angles.

Well, that's an interesting one, isn't it? 'Cause Jun's now saying, "If you zoom in really closely on this example, then actually where these two lines meet, the lines are straight, aren't they?" Can you see that here? So we could say that actually these two lines form to make an angle, don't they? Because the lines are straight at the point when they meet.

Okay, time for you to check your understanding now then.

Can you tick the images that show an angle? Well done, it's these two here, isn't it? And again, what'd you notice about those? The length of the lines are different, aren't they? And also the thickness of the lines are different on one of the examples, but it doesn't matter.

They still create angles, don't they? These two here would also create angles, wouldn't they? What do you notice about these two? Again, the length of the lines are different, aren't they? But also on one of them in particular, we've got a dashed line, haven't we? We often use dash lines to represent lines when we're trying to separate them from a normal line.

Often these dash lines can represent a normal line, so we would say here that this also shows an angle as well.

Hmm, so we can create some of our own angles, can't we? And we can use two bits of card and a split pin to create something which will enable us to make our own angles.

Let's have a look.

Here's one piece of card and here's another piece of card.

And if we join both of those with a split pin like so, we can now rotate either one of the strips, can't we? To create an angle.

There we go.

So have a look at these two here.

Laura's saying that her angle is bigger than Jun's.

Do you agree? Well, there's one way to find out, isn't there? We can overlay the angle strips on top of one another to see this.

There we go, that's more clear now, isn't it? We've lined up one of the lines of each of the angle strips on top of each other and now we can see how much of an angle has been created by the other line on our angle strip.

So you were right, Laura, the angle that you created was a large angle than the one that Jun had created.

Okay, time to check your understanding again now then.

Who has made the largest angle? Take a moment to have a think.

That's right, it's C, isn't it? Whoever created angle C has created the largest angle in this example.

Okay, and time for you to practise now.

What I'd like you to do here is to create your own angle strips and to measure as many amounts of turn that you can in the place where you are right now.

An example of that might be a cupboard door.

You could open a cupboard door and measure the amount of turn that takes place as the cupboard door opens.

You could also ask a friend to spin or rotate around ever a slightly, and then measure the size of the angle that may spin or rotate.

I wonder how many turns you could find for yourself.

Good luck with that task and I'll see you back here shortly.

Okay, let's see how you got on them.

Here's an example that Laura found.

She found the door handle and we could see that the door handle has turned, hasn't it? And now we can apply our angle strips to identify the amount of turn that took place for the door handle.

I wonder if you've managed to find that one or something similar for yourself.

Okay, that's the end of cycle one.

Let's move on to cycle two now then.

Let's look at different types of turn.

So the pupils in Year 5 at Oak Academy have gone on a school trip to London.

Jun's saying that he hopes he doesn't get lost on the Tube.

Well, don't worry, Jun, make sure you wear something bright and colourful so you can be easily noticed by your teachers and also stay close to your group at all times.

Laura's wondering if the king will be at home for a cup of tea.

Well, I'm not quite sure, Laura, because the king has many homes across the UK.

And not only that, I'm pretty sure he is got quite a busy diary.

As a part of their trip, the class were able to go on the London Eye.

Let's have a look here.

Jun's saying he started on this capsule here, and that's right.

When you get on the London Eye, you have to start at the bottom obviously.

That's the way you get onto the London Eye.

So they started in this capsule here and he says that he saw Buckingham Palace best when the London Eye rotated and his capsule was in this position here.

How far did he turn? Well, we can draw some lines on to represent the distance of turn that has taken place.

Laura's saying approximately that the distance from the ground view to the view of Buckingham Palace was a quarter turn.

Do you agree with Laura? That's right, I'd agree with you, Laura.

That's a good estimate that because a quarter turn we know creates a square corner and it looks like these two lines have created a square corner where they meet.

Bearing in mind where we started at the bottom, Jun is now saying that he thinks he saw the best view of St.

Paul's Cathedral when his capsule rotated to this position here.

How much of a turn has he done here from the ground view to this position? Well, if we draw our lines on, we can see that they make a straight line, don't they? So the amount of rotation here, we could say, is a half turn.

Approximately, the distance from the ground view to the view of St.

Paul's Cathedral is a half turn.

And here's one more example as well.

Remember where we started from the ground view.

Jun is now saying that he thinks the best view of seeing The Shard was when his capsule rotated around to this position here.

Hmm, I wonder how much he's rotated this time.

Let's draw our lines on to help us.

There we go.

Hmm, how much has he rotated round? That's right.

We have to remember that the London Eye rotates in a clockwise direction.

So it's a rather large angle that he's rotated here, isn't it? Yap, and that would be right, Laura.

We can see that Jun's capsule would've rotated about a three-quarter turn to get all the way around to see The Shard from that point of view.

Well done if you noticed that for yourself too.

Laura is now gonna share some of the other landmarks that she saw on the way round.

She saw Hyde Park best from this angle, she saw Buckingham Palace best from this angle, she saw Wembley Stadium best from this angle and St.

Paul's Cathedral was best seen from the very top.

She saw the Olympic Park from this angle and she saw The Shard best when her capsule was at this point.

And finally, Cutty Sark was best seen from this point as well.

So Laura's asking how much turn did she go through from the best viewing point of Hyde Park to the best viewing point of Wembley Stadium? Well, let's have a look.

Here was the best viewing point of Hyde Park and here was the best viewing point of Wembley Stadium.

Take a moment to have a think for yourself.

How much do you think that her capsule rotated between the view of those two landmarks? Let's draw our lines on.

There we go and we can see.

And again, that to me looks like a quarter turn.

Yap, so you'd be right there, Laura.

That looks like the capsule rotated from the best view of Hyde Park to the best view of Wembley Stadium about one quarter turn.

Jun's now asking, "How much did we turn from the best view of Wembley Stadium to the best view of the Cutty Sark?" Well, let's find Wembley Stadium and the Cutty Sark.

And we can see here that our two lines create a straight line again, don't they? As soon as we create a straight line, we know that we've turned a half turn, haven't we? So the amount of turn that took place from Wembley Stadium to Cutty Sark was a half turn.

Okay, time for you to check for understanding now then.

Something is approximately a half turn from Buckingham Palace.

Take a moment to have a think.

There we go, we can draw on our lines from Buckingham Palace and we can draw on the half turn, which takes us to The Shard.

So the capsule rotating a half turn from the best view of Buckingham Palace would allow us to see The Shard, wouldn't it? Okay, and another quick check, which landmark view is about a quarter turn from St.

Paul's Cathedral? Take a moment to a think.

Well, if we draw on our line from St.

Paul's Cathedral and then draw on a line, which would be a quarter turn, we can see that it would also be The Shard, wouldn't it? The Shard is approximately a quarter turn from St.

Paul's Cathedral.

Okay, time for us to have a go at our task now then.

As the London Eye rotates, it stops at each position and we've given each position a number.

We can see that the positions have been marked on the outside of the wheel.

What I'd like you to do is complete the sentences with approximations.

Identify how much of a turn has taken place from each position.

Once you've done that task, what I'd like you to do is find at least three different solutions for each one of these columns.

So find three turns that are less than a quarter turn, find three turns that are less than a half turn, but more than a quarter turn, and find three turns that are less than a full turn, but more than a three-quarter turn.

Good luck with those two tasks.

And when you're done, come back and we'll go through your answers together.

See you shortly.

Okay, welcome back.

Let's complete these sentences then.

Position six to position 30 is approximately a three-quarter turn.

Position 15 to position 32 is approximately a half turn.

And position nine to position 16 is approximately a quarter turn.

And here are some examples of some of the positions that you could have started in and rotated to in order to fit each of these columns.

So for rotations that were less than a quarter turn, you could have started at position seven and finished at position 11.

You could have started at position 19 and finished at position 20.

You could have also started at position 26 and finished at position 30.

They're just three examples.

You may have some of your own.

Examples that were less than a half turn, but more than a quarter turn could be position 14 to position 26, position 18 to position 29 or position four to position 15.

And finally, more examples that could have been less than a full turn, but more than a three-quarter turn would be, for example, starting at position two and finishing at position 32, starting at position four and finishing at position 31 or starting at position one and finishing at position 27.

Once again, you may have had some of your own examples for those and you might want to check those with a partner or someone nearby you to see if they agree with you.

Okay, that's the end of our learning for today then.

To summarise what we've been thinking about then, we can say that different objects can turn or rotate.

When an object turns or rotates, an angle is created.

An angle is where two lines meet at a fixed point and the length or width or shape of the line doesn't matter as long as the lines are straight at the point at where they meet.

Thanks for joining me for that lesson today.

Hopefully, again, you're feeling more confident about what angles are and how they relate to turns.

Take care and I'll see you again soon.