Lesson video

Hey everybody, I'm Miss Miles.

And over the next few weeks, we're going to be doing some maths together.

Maths is my favourite subject, because I love reasoning and looking at problems together.

And hopefully you'll have nice time doing that with me over the next few weeks.

Every day, I'm going to start with digging out fact.

Today's fact is, did you know that in a room of 23 people, there's a 50% chance that two of those people will have the same birthday, but you didn't know that one.

So, today, we're going to start a new unit and we're going to be looking at 2D and 3D shapes.

For today's lesson, you need to make sure that you have got a pencil, a piece of paper and the clear workspace.

And you also need to make sure that you have done the pre-lesson quiz.

So let's have a look at what we're learning today.

In today's lesson We are learning to identify, compare and classify shapes.

So, if you're ready, let's get started.

So, you will see on your screen now there are two questions that I would like you to have a think about.

The first question is, we talk about 2-D shapes, and we talk about 3-D shapes.

But what does the 'D' in 2-D and 3-D actually mean? Also, can something be 1-D or 4-D? Pause your video there and have a think about that, and then we'll discuss it together.

So, in 2-D shapes and 3-D shapes, the 'D' in both of those terms means dimension or dimensional.

And we can have something nice one day and we can have something that's 4-D.

So let's go through them together.

So something with no dimensions at all is a point.

Something that is 1-1D is a straight line, because it has one dimension, it has length or height.

Something that is 2-D is a flat plane or a flat shape, because it has two dimensions.

It has length and width or length and breadth.

A three dimensional shape is something that you can pick up in your hands, it's things that we see in the real world, may have three dimension.

They have length, width, and height, or they have length, width, and depth.

And 4-D is when we have all of those things, but we have an extra dimension added.

This could be time or something else.

You might have even been to a 4-D cinema and experienced that for yourself.

Just to show that a little further.

here is an image of a cube that has got the three different dimensions marked on with three different coloured arrows.

So we can see that one dimension is measured with a blue arrow, it is height, we have a green arrow showing width, and a red arrow showing depth.

The real world that we live in has three dimensions.

If we can pick something up, it is three dimensional.

So, let's have a look at some mathematical vocabulary now.

These words on screen are words that we would use when we're describing different shapes.

These words are sides, edges, vertex or vertices, and faces.

I would like you to pause the video there and have a think about what those words mean and how you might use them.

And then when you're ready, press play and we'll look at the definitions together.

Here is the definitions for those pieces of mathematical vocabulary.

So, side this is the line segment that joins two vertices in a 2-D shape.

Vertex or vertices, the point where two lines meet together.

A vertex is one point, and vertices is when we have multiple points.

Face is a flat surface, which ones part of a 3-D shape.

An edge.

this is the line where two faces meet in a 3-D shape.

It's similar to sides in a 2-D shape, but you must be careful because when we're talking about 2-D shapes, we use the word side, and when we're talking about 3-D shapes, we use the word edges.

So, here on screen now you can see two different shapes, and I'm going to show you how I would describe them using the terminology that we have just discussed.

So, I can say that shape number one is a 2-D shape.

It is a fact plane.

It is a Pentagon, and this is a regular pentagon, because it has five sides that are all of equal length.

It also has five vertices or five points, which means that it also has five angles.

My second shape is a 3-D shape, and it's hard to show that on a screen.

So I have a little cylinder here with me.

Empties.

So I will describe this one to you now.

Now this is 3-D cos I can pick it up in my hands.

It has a third dimension to it.

I can see that it has one, two, three faces.

The two faces one at either end are both circular and it has a curved face between.

It has two edges hit one here, and one here where the faces meet one another, and it has no vertices, because there are no points.

So that's how I would describe those shapes.

Now it's your turn, on the screen, you can see two more checks.

I would like you to pause the video there and have a think about how you would describe them using those pieces of terminology.

And then we'll go through them together.

Pause the video there.

So, shape number one again is 2-D, it is a flat plane, I can see that it is a hexagon as it has got six sides, and it is also got to six vertices or six points.

My second shape is a cube and it is 3-D.

Again, I've got a little cube with me to show you.

I know that my cube has got one, two, three, four, five, six faces and all of the faces are square.

I can see that it has got one, two, three, four five, six, seven, eight, nine, 10, 11, 12 edges and it has one, two, three, four, five, six, seven, eight vertices, Did you get the same answers as me? Now to practise that a little further, there is a table on screen, I would like you to draw in your books and I would like you to fill it in.

So down on the left hand column are the different names of the shape.

So those square, a heptagon, an octagon, square based pyramid, sphere and the cone.

And across the top are the different properties.

So the number of dimensions, the number of edges or sides, the number of vertices and the number of faces.

If it's a 3-D shape.

I would like you to pause the video, draw out the table and fill it in correctly.

Okay, here are your answers.

Have a look at the table on screen and have a look at the table you have drawn and see how you got on.

Did you get the same answers? If not don't worry edit it and correct yourself, and then we'll move on.

So we've had a look at the different properties of shapes now and how we can describe them, and now we're going to have a look at lines.

Now, in year four, you will have learnt about lines then and the different terminology for them.

So this is a little bit of revision, a little bit of extra practise.

So, right angles.

A right angle is an angle of exactly 90 degrees, and that is the same as a quarter turn.

I can show one with my arms. So I start here, which is flat and then I will move it a quarter turn to show a right angle.

I have drawn a right angle here, and I have shown you how to mark a right angle on.

So here are my two lines here that meet a right angle.

And I've drawn a little box here, to show how you mark a right angle on.

If drawing one, this is how you would show it.

So, I would like you to have a look at the different sets of lines on screen now, and I would like to pause the video and identify any right angles in the sets of lines on screen.

Pause the video now.

Okay, hopefully you notice that the sets of lines two and three both show right angles shape.

So in lines number one don't show a right angle because it is not directly a quarter turn.

Next, so perpendicular lines.

Perpendicular lines are a pair of lines that meet at a right angle.

So it's similar, but it's where those two lines meet together to form a right angle.

So on the screen now you will see three different shapes.

I would like you to pause the video and identify any sets of perpendicular lines.

Okay, hopefully you noticed that all three of the shapes on screen have sets of perpendicular lines, because they all have right angles in them.

So, it's time now for your independent task.

There are a range of different tasks today for you to work through.

And they apply knowledge of the lines that we've looked at, and the shape properties that we've looked at.

So work through them as you wish.

This is task number one.

So there are three sets of lines on screen A, B,.

For each of the sets of lines, write how many perpendicular lines they have, and how many right angles.

Do you see a pattern? Pause the video there and have a go at that one for me.

Task two.

Can you identify lines that are perpendicular to each other, would meet at a right angle, circle them in different colours.

If you were drawing these out, you could perhaps draw them in different colours.

If you want to see any of these tasks on a slightly bigger screen, just open the worksheet and move on to the next part.

If not, stay with me.

Okay.

Our next task.

Our next task is to have a look at the properties of these three shapes.

You have shape A, B, and C.

I would like you to write the name of each shape.

I would like you to write down three of the shapes properties.

And I would like you to identify how many right angles and perpendicular lines it has.

So this has all of our learning from today's lesson together for you to practise.

So have a go at that one for me.

Pause the video there.

And then finally, you have got three lines here, that I would like you to draw out.

What I would also like you to do is draw on another line, that would show the line on screen meeting a new line at a right angle.

Pause the video there and have a go at that one.

So let's have a look through our answers together now.

Here we go.

This was task one.

This is where we had to identify a perpendicular lines and right angles.

So in A we can see there are two right angles and there are two sets of perpendicular lines.

B has no right angles and no sets of perpendicular lines.

And C has four right angles and four sets of perpendicular lines.

Have a check of your answers.

See how you got on.

If you need to make any corrections, please do.

Editing is just as important as when we complete the first time.

Task two.

So this is where we had to draw other lines or mark them the perpendicular sets on with different colours.

So we can see that the two red lines form perpendicular lines, the green lines, the purple lines, and the blue lines are all perpendicular to one another.

There are also some sets of lines that would match up with other colours.

So the vertical blue line and the horizontal purple line, and the horizontal purple line and the vertical blue line are also perpendicular with one another.

Likewise with the green and red.

And then this was a task to describe our properties.

So shape A, shape B and shape C above each of those shapes is a list of their properties.

And it also shows that right angles and perpendicular lines.

Have a look through what you've got, what answers you got, and have a look through the answers on screen.

See how you got up, make any changes if you need to.

And finally, here are our lines where we had to draw a extra lines to make right angles.

So here, they actually drew down two more sets of lines on to show two different right angles.

But if you just drew one, that's absolutely fine.

Again, check your answers and make any changes if you need to.

Okay, well done for completing today's lesson.

I hope you enjoyed it.

Please don't forget your end of lesson quiz.

And hopefully I'll see you very soon.