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 identify and describe right angles and it is from the unit, right angles.

By the end of today's lesson, you will be able to identify a square corner as a right angle and you will be able to find and identify right angles in the environment.

There is just one keyword for today's lesson.

Let's practise saying it.

My turn, right angle.

Your turn.

You are going to find out the meaning of right angle, throughout this lesson, so listen carefully.

There are going to be two parts to this lesson.

To begin with, we are going to learn that square corners are right angles and then in a little while, we are going to be creating, finding and identifying right angles.

There are going to be two children who help us in this lesson.

Their names are Jacob and Sam.

Look out for them throughout this lesson because they sometimes have some really useful and helpful things, that they can tell you, that will improve your understanding.

Jacob is using some angle strips to measure the vertices of these shapes.

He can place his angle strips on each vertex, like this.

He has noticed something.

What do you notice about the vertices of these shapes? Let's have a look.

Jacob thinks that all these angles are the same size.

Let's check by placing all of the angle strips together and now let's rotate them so that they're all facing the same direction.

Now you can see that all of these angle strips have made the same type of angle.

Jacob says, these are all square corners.

These shapes all have square corners.

You might have learned about square corners before.

Rectangles and squares always have square corners like this.

Jacob says, if I used my angle strip, these vertices would all be the same size.

He's not going to do that because he can already see, that all of these vertices are the same.

The mathematical name for a square corner like these is a right angle.

Each shape has four right angles.

You can see them here.

One, two, three, four.

Can you use an angle strip to make a right angle? Try to make it look like the corner of a rectangle or the corner of a square.

If you need to go and make some angle strips first, just pause the video and you can go and do that now.

Okay, I hope you've all found your angle strips and you've had a go at making a right angle.

Here are some examples of what it might look like.

All of these are different ways that you can make a right angle with your angle strips.

Jacob says, I can see the square corner in each right angle.

Have a look at yours.

Perhaps you could trace your finger along it.

Can you see the square corner in your right angle? Let's check that you can recognise a right angle.

Who has made a right angle with their angle strip? Do you think it's 'a', 'b', or 'c'? The right angle is 'a'.

Well done if you said 'a'.

You can check which one is a right angle.

Remember, a right angle is a square corner, so let's take a square or a rectangle and place it behind the angle strips to check.

You can see that 'a' is the same as the rectangle.

'B', the angle strips haven't turned enough, that angle is too small, and 'c', that angle is too big.

It is 'a' that shows the right angle.

Now Jacob and Sam have got some different angle strips.

Jacob says, my right angle is larger than yours.

Let's check if Jacob is right.

If we place one on top of the other like this, you can see that Sam is right.

We both made right angles, the angle is the same.

All square corners are right angles.

It doesn't matter if the lines are long, or short, or thick, or thin.

Sometimes the lines might even be different lengths to each other.

Let me show you some right angles so that you can see.

A right angle might look different, but they always have a square corner.

Have a look at these.

Can you see the square corner in each of these right angles? Even though some of the lines are different, some are thick, and some are thin, and some are longer, and some are shorter, these are all right angles.

Let's check if you can spot the right angle this time.

Could it be 'a', 'b', or 'c'? The right angle is 'b'.

Well done, if you said 'b'.

Like before, you could check by taking a square or a rectangle and placing it inside the angle.

So this one, you can see, the angle of the rectangle is the same, so this is a right angle.

On 'a', the angle is too small and on 'c', the angle is too large.

A right angle is the same as a quarter turn.

Watch the hand on the clock to see a right angle or a quarter turn on the clock.

When the hour hand turns from 12 o'clock to 3 o'clock, it is a quarter turn.

Sam says, I could use my angle strip to show that this is a right angle.

If we place Sam's angle strip over the clock, you can see, that between 12 and 3, the turn is a quarter turn, which is the same as a right angle.

Jacob says that he knows another way to find right angles.

Let's have a look, what does he do? He says fold anywhere on a piece of scrap paper.

Fold it again, make sure it lines up along the first fold.

The arrow is pointing to a right angle.

If you fold a piece of scrap paper twice and you make sure the second fold lines up with the first one, you will create your own right angle.

Now Jacob can use his right angle piece of paper to find right angles on the clock.

If he places it here, he can see that the angle lines up with the 9 and the 12, so the turn between 9 and 12 is a right angle.

If he places his right angle here, he can see that it lines up with the 10 and the 1, the turn between 10 and 1 is a right angle.

Could you get a piece of scrap paper and make your own right angle by folding a piece of paper like Jacob? Remember, fold it anywhere on the piece of paper, then fold it again and make sure that your first fold lines up with your second fold.

If it doesn't go right to start with, just get another piece of scrap paper and have another go.

Pause the video if you need a bit of time to do this.

Well done everybody.

Now you are going to go and use your right angle that you've just made, to complete this piece of work.

I would like you to use your right angle from folded paper and place it on the clock to complete the sentence in as many different ways as you can.

The turn between mm and mm is a right angle.

Have your right angle, folded up, piece of paper ready and off you go.

Well done.

Let's have a look at some of the possible ways that you could have completed this sentence.

If you place your right angle here, you can see it lines up with 11 and 2, so you could say the turn between 11 and 2 is a right angle.

If you place it here, you could say that the turn between 2 and 5 is a right angle.

I wonder if you found those ways and I wonder how many different ways you found to complete the sentence.

Well done for thinking about that really carefully.

Now you are going to move on to the second part of this lesson and you are going to be thinking about creating, finding and identifying right angles in different places.

Jacob has been looking around and he has found some more right angles in other objects around him.

He found a right angle in a card, from a game, in the door, and in the ruler, and Jacob says there are so many right angles all around us.

I bet if you look around you could find some.

I can see a box in the corner of my room that has a right angle and I can see a book next to me that has a right angle.

Which object do you think has at least one right angle? Do you think it's 'a', 'b', or 'c'? The object with at least one right angle is 'b'.

It actually has one, two, three, four right angles.

You could use your right angle folded up piece of paper to check that the others don't have a right angle.

If you place your folded up piece of paper, under the slice of pizza, you can see that the angles are not the same and if you place it under the scissors you can also see that the angles are not the same.

Now, I would like you to be like Jacob.

Can you use your folded up piece of paper to see if you can find some right angles on some of the objects that are around you? I talked about the box in the corner of my room, I wonder what you are going to find.

Pause the video and start having a look for those right angles, off you go.

Well done.

Let's have a look at a couple of examples, but I'm sure you have found lots and lots of right angles around you.

Jacob found a right angle in this sheet of paper.

Sam found a right angle in this building brick.

Now we can see some capital letters.

Jacob thinks that he can see right angles in some capital letters too.

He's going to use his right angle checker to show where they are.

You can see a right angle here.

You can see a right angle at the bottom of the capital E.

You can see one on this side of the I.

You could see one on the other side of the I and I bet you can see even more than the ones Jacob has just shown you.

There are lots of right angles in capital letters.

Can you find which capital letter has at least one right angle here? Is it 'a' the H, is it 'b' the W, or is it 'c' the A? Pause the video and have a think.

The capital letter with at least one right angle is H.

You can see that there's one here.

If we use our right angle checker on the other letters, we can see, the W, doesn't have a right angle and the A doesn't have a right angle.

Now I would like you to see if you can think of your own capital letters that have at least one right angle.

You might want to work your way through the alphabet and see if you can think of which capital letters would have a right angle.

You can write them down and use your folded paper to check.

Pause the video and have a think.

Which capital letters have at least one right angle in them, off you go.

Well done everybody.

There are so many capital letters that have right angles aren't there? Here are a few of them.

You could have had the letter L or the letter T.

You can see the right angle is here, in the L, and the T has two.

I bet you found lots more as well.

Well done.

Now it's time for you to go and do your next piece of work.

You are going to fill in this table by using your folded up piece of paper to check if each object has a right angle or not.

If it does, you're going to put a tick, in the 'has a right angle' column, and if it doesn't you can put a cross in the 'has no right angles' column.

First, I want you to go and check a table, a book, and a leaf, and then for the last two rows, I want you to choose your own object and show if it had a right angle or not.

Once you've finished completing the table, you're going to have a go at doing some sorting.

This table has a column for right angle and a column for not a right angle, and at the side there are six drawings labelled, A, B, C, D, E, and F.

I would like you to write the letters, so that you put each drawing into the correct part of the table.

Then I would like you to draw your own examples.

The first box says typical.

That means I want you to draw, what you think is a normal looking right angle.

The second box says unusual, so in this one I want you to draw a right angle that you think looks a little bit different to the typical right angles that you are used to seeing.

In the last box, I want you to draw something that is not a right angle.

Are you ready to go and do some sorting into the table? Excellent, off you go.

Well done everyone.

Let's have a look first at these objects and whether they have a right angle or not.

You should have found that a table has at least one right angle and a book has at least one right angle.

A leaf does not have a right angle.

The last two rows, you were allowed to choose your own object.

I chose the laptop screen and I could see that that does have a right angle on it and then I chose a star shaped sticker and I could see that the star shaped sticker does not have a right angle.

I wonder if you managed to find something that does have a right angle and something that doesn't, or if both of your items had right angles in or maybe both of your items had no right angles.

Well done for using your folded up paper to check.

Now let's have a look at the second task.

You needed to sort the drawings into right angle or not a right angle.

So let's start with A.

A is a right angle.

B is not a right angle.

C is not a right angle.

D is a right angle.

E is not a right angle, and F is not a right angle.

Then you have to have a go at drawing your own.

Now your drawings might look the same as these or they could look different, but listen carefully because your reason for drawing them should be the same.

A typical right angle, I've said, looks like this.

I've got one line pointing straight up and one line pointing across.

I've drawn a square corner, like you would expect to see on a rectangle.

For my unusual right angle, I've drawn one where one of the lines is longer and one of the lines is shorter.

I also chose to draw it so it looks like it's been rotated rather than one line pointing straight down and one line pointing straight across.

For my 'not a right angle' drawing, I drew this, so I drew something that has no fixed point.

Perhaps you drew something with no fixed point or you might have drawn something that was smaller, a bit like the angle in B, or you might have drawn something that was bigger, a bit like the angle in C or you could have drawn something that's not an angle at all like I have.

Now that you are at the end of the lesson, you know that square corners are known as right angles.

You know that a right angle is a quarter turn.

You've learned that right angles can be found in lots of objects all around us.

You know that the lines can be different lengths or different thicknesses and they can be different orientations.

If it is a square corner, it is a right angle.

You have thought really carefully about right angles in this lesson.

Well done for all your hard work today.

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

Bye, everyone.