Hi, everyone, thank you so much for opening up your design and technology lesson today.

I'm super excited to see that you're here with me.

My name is Miss Larham, and I'm your design and technology teacher.

I'm having great fun in this unit so far, and I hope you are too.

We've got another fun lesson ahead of us today.

So let's get started.

So we are on lesson seven of our structures unit, where we're learning all about freestanding structures.

Do you remember last lesson? We had a go at making a prototype bridge out of spaghetti, didn't we? That was so much fun.

And we learnt about triangles, and how important they are in our structures.

Remember when we've got our square shapes, they're not very rigid.

They can move around really easily, can't they? But if we turn that square into two triangles, it becomes rigid.

I now can't move that square shape at all.

Today, we're going to be investigating and testing.

That's my favourite thing to do.

Let's see what equipment you'll need for today's lesson.

In this lesson, you will need some building blocks, some cardboard tubes.

Now, don't worry if you haven't got any cardboard tubes.

We know how to make these from paper, don't we? We can always make our own.

Going to need some tape, and you're going to need some scissors.

And scissors must be used under the supervision of a parent or a carer.

That's really important.

Let's take a look at what our lesson is going to look like today.

First, all together, we're going to start with our intro quiz.

Then, we will do our star words.

Then, we're going to be looking at some of the tallest towers.

Then, you will do your talk task.

Then, we're going to do some science learning.

We're going to learn about the centre of gravity and bases.

Then, you will do your independent learning.

And finally, we will finish all together with our exit quiz.

It is intro quiz time.

I've got a question for you.

I'm going to show you two towers.

Here is my first tower and here is my second tower.

Let's put them side by side.

Hmm, which tower is the tallest? I'm going to put them closer to you.

Can you tell me? Point to your screen.

Which tower is the tallest? Point now.

Which one's the tallest? Let's see if you're right.

Did you have your finger on this one? Well done, it is taller than this tower.

We can see that because the cubes go higher than this tower.

Well done if you knew this tower was the tallest.

Well done.

It is star words time.

I hope your voices are ready, and I hope you're ready to join in because remember, we do my turn, your turn.

Are you ready? Let's see our first star word.

My turn, stability.

Your turn.

Thank you for joining in.

Let's try again.

Stability.

Well done.

We've come across the word stability before, haven't we? Stability means, how likely is it to fall over when a little push is applied? So how likely is it to fall over if we give it a little push? We want our structures to be stable, don't we? So they don't fall over.

Our next star word is, my turn, base.

Base.

Well done, and do you remember when we looked at bases in our other freestanding structure lesson? This is the lowest part of the structure where something is resting or supported on.

So we use the base to apply something onto there to hold it strong and stable.

Our next star word is centre of gravity.

Well done.

That was a long one, wasn't it? Centre of gravity.

Well done.

We're going to learn about the centre of gravity, so don't worry if you don't know what that is just yet.

And our last star word for today is buttress.

Well done.

Buttress.

Well done, and we're going to be talking about that star word a little bit later in our lesson as well.

Well done for joining in, everyone.

Now, we're going to have a look at some of the tallest towers.

Do you know any really tall towers already? Are there any tall buildings near where you live? Let's have a look at some of the photographs of my tallest buildings.

So this first tower is the Burj Khalifa in Dubai, and this tower is 829 metres tall.

Just look at those palm trees at the bottom of the photo.

It really shows you how tall that building is, doesn't it? This is the next photograph, and this is the Shanghai Tower, and this is over 600 metres tall.

Look how much taller it is than all of the other skyscrapers around it.

And finally, you might recognise this building.

This building is the Shard in London, and this is 300 metres tall.

Wow, these really are tall towers, aren't they? They're some of the tallest in the whole world.

Whoa! Those towers really are tall, aren't they? Let's just take a moment to think how tall they really are.

Now, me, Miss Larham, I'm about one and a half metres tall.

So that means you would have to put 552 of me, one on top of the other, to be as tall as the Burj Khalifa in Dubai.

So 552 Miss Larhams, one on top of the other, and that would make me as tall as the Burj Khalifa.

Whoa! That's a lot of Miss Larhams in a tower, isn't it? Now, it is our thinking and talking time.

So I'm going to set you up on a talk task.

Now, your talk task today is all about the word gravity.

Have you heard of this word before? Talk about what you know about gravity.

How could gravity affect our freestanding structures? So pause the video now, think about all you know about gravity so far, and link that to our freestanding structures, and then press play when you're ready, off you go.

Welcome back from your talk task.

I wonder how much you know about gravity already.

Now, did you know that gravity was discovered by Sir Isaac Newton? He discovered that gravity pulls things towards the Earth.

So when things come falling towards the Earth, it is gravity that is pulling them down.

Without gravity, we would be floating around everywhere.

It is gravity that pulls us towards the Earth and keeps our feet on the floor.

Now, we're going to be thinking about how gravity affects our freestanding structures.

So we're going to be thinking about the centre of gravity and bases.

Now, the centre of gravity is the point where gravity seems to act.

The centre of gravity decides whether a structure will stand or will fall over.

The position of the centre of gravity of an object affects its stability.

Let me show you.

So here, I've got a tower of building blocks.

I'm going to show you that the centre of gravity and where that is placed affects how easily the freestanding structure will fall over.

It shows you how stable it is.

So if I say that the centre of gravity is at its lowest, so it's a low point in the building.

If I give it a push, my building does not fall over.

And what would happen if the centre of gravity was in the middle and I give it a push? It falls over quite easily, doesn't it? Now, let's see what the centre of gravity is like at the top of the building.

So I'm going to push it at the top.

That falls over really quickly and really easily, doesn't it? So the centre of gravity, when we push our building, it shows how stable it is.

Which point was the most stable? At the top, in the middle, or at the bottom? Can you have a think? Brilliant.

Can you tell me? That's right.

It was at the bottom, wasn't it? So it was most stable when the centre of gravity was at the bottom.

It didn't topple over.

It just moves with my finger.

In the middle, a slow topple.

At the top, a quick topple over.

Now, if we add a base to our tower, this will also increase the stability of our tower, so adding a base to the bottom.

The bigger the area at the bottom, the bigger the base, the more stable it will be.

I want everyone to stand up for me.

Okay, so is everybody standing up for me? Well done.

Now, what I would like you to do is put your legs tight, close together and your arms by your side.

Can you do that now for me? Copy me.

Well done.

Now, I want to start swaying, pretending it's a windy day, quite stormy.

Ooh, nearly fell over.

You try.

Wiggle yourself around in the wind.

Oh, did anyone else fall over like me? We're all tucked in and we're rolling around.

We are not very stable, are we? Hmm, I wonder what we could do to make ourself more stable in the wind.

What did Miss Larham just teach us about bases? That's it.

Making a wider base.

So let's take our feet a little bit apart.

Hands by your side.

Now, here comes the wind again.

Rolling round.

Oop! Keep rolling.

Pretend it's really windy.

Oop! Oh, still falling over a little bit.

How could we make ourselves even more stable? What do you think? That's right.

Let's widen our base even more.

Take your legs really wide for me and now let's try the wind again.

I haven't fallen over this time.

You try it with me.

Whoa! Because I made myself a really wide base, when I moved around, I didn't fall over.

I was much more stable.

I wonder, let's try bending our knees and seeing if that makes a difference.

So being even more stable.

Give them a little bend.

Rolling around.

Do it with me.

I am so stable, I haven't fallen over at all.

I wonder.

Those rugby players do that, don't they? When they're going to be tackled by their rugby players, they don't stand like this, do they? 'Cause, ooh! They would fall over really easily.

If they stand like this, wide legs, bit bent, ready to be tackled, they won't fall over, will they? Wow, so remember, wide base makes us much more stable than a thin, whoop! Narrow base.

Great learning, everyone.

So we now know that by adding a wider base to our structure, it makes it more stable, so you could make it a base.

You could also create a buttress.

Now, a buttress is the supports at the side of the structure that help that when there's a sideward force, a sideward push, it doesn't fall over, and it's much more stable.

You're going to do an activity now based on our learning so far.

Now, you're going to explore by building me a tower with your building blocks.

So I want you to try out the centre of gravity with different sized towers.

So this is quite a short tower at the moment.

So testing out its centre of gravity.

And then, you can make a taller tower and check the centre of gravity.

You might also explore adding bases or buttresses to your tower to make it more stable.

So for example, I can make myself a base to this tower, and we can now check if it's more stable.

So when I push at the top, remember, that's our weakest point of gravity, isn't it? It now doesn't fall over by adding a base.

So it's your turn to explore now.

Build me lots of different size towers.

Which one's more stable? A shorter tower or a taller tower? Can you add in a base or a buttress to make it even more stable? Don't forget to press play when you've had your try.

Welcome back, everybody.

I hope you managed to explore and find out the most stable tower that you could.

Was it a short tower? Was it a tall tower? How big were your bases? Did you manage to add any buttresses? Well done for having a try for me.

We're going to move on to our independent learning time now.

So for our independent learning task today, we're going to be thinking about the story of Jack and the Beanstalk.

You might know that story already.

If you know, you can join in with me.

Once upon a time, there lived a little boy called Jack, and he lived with his widow mother, but they were very, very poor.

They didn't have any money, and now they didn't have any food to eat.

Mother didn't know what to do.

And one day, she said to Jack, "Jack, we're going to have to sell our cow.

"I need you, Jack, to take her to market "and get a really good price for her.

"Don't come back unless you've got some money for us "for our beloved cow." So Jack said, "Okay, mother.

I'll take the cow to market." So Jack took the cow, and as he was walking along, he bumped into this funny looking old man.

And this funny looking old man said, "Hi there.

Where are you off to?" So Jack replied, "I'm off to market "to get some money for our cow.

"We have no food and we need some money to survive." The little old man said, "I will buy your cow from you." And from his pocket, he took out some beans.

Jack said, "Beans? "No, I need money for this cow.

"If I go back to mother with no money, "she's going to be terribly cross." But the funny little old man said, "But these, Jack, are magical beans.

"If you plant these, magical things will happen." Hmm, Jack took a few moments to think, and then he decided, "Okay, magical beans.

"That sounds super exciting." And they handed them over.

So Jack gave over the cow, and he took the magic beans from the little old man.

Jack was really happy with himself, and he skipped all the way home.

When he got in, his mother said, "Well? How did you get on? "How much money did you get for our cow?" Jack, really proud of himself, said, "I got something even better, mother.

"I got magical beans." Mother was furious and shouted at Jack, "Jack, how dare you? "I asked you to take the cow to market to get us some money.

"Give me those beans." So Jack, with his sad face, handed over the beans to mother.

And mother was still so cross.

She threw them out of the window, and Jack was sent straight to his room for the night.

So do you remember what happened the next day when Jack woke up and looked out of his curtains? What did he see? What had grown in his garden? Do you know? Can you tell me if you do? That's right, a huge beanstalk had grown all the way into the clouds.

Now, shall we see if we can make our own beanstalk using some of our tubes? Let's try.

Let's try and make it the tallest that we can.

Because remember, the beanstalk grew all the way up into the sky, into the clouds.

So I'm going to see if I can make a tower using my tubes.

Let's think.

How am I going to join these together? I'm going to use some of my tape.

Cut the tape.

That's it.

And then, I'm going to wrap the tape around the two tubes to join them together.

Do this really accurate.

Take your time.

Make sure it's nice and neat, and they're held together really straight.

So I've joined two tubes together, so it's getting taller, isn't it? I wonder if I could add two more? Yes, let's do that.

Going to make it as tall as I can.

Cut some more tape.

Join them together.

I might add even more, but let's see.

Let's see if it's nice and stable.

Ooh, it's very wobbly.

Ah! It's not very stable, is it? It falls over even when I push it at its low centre of gravity.

Oh no! So we can make this even taller.

Remember, the taller it gets, the less stable it will be.

So I wonder, can you use the base to help it be more stable? Or could you add in a buttress to make its base wider, like we practised with our legs? So your challenge now is to make me a really tall tower.

But it's got to be stable.

So will you use a base or will you use a buttress to help you do that? It's your time to have a go.

Have fun.

See you soon.

Welcome back, everybody.

How did you get on with building the tallest beanstalk for Jack that you could? And remember, it had to be stable.

So that means when a force is pushed on it, it doesn't fall over.

I've given mine a go.

Here it is.

So I decided to put my structure on a base, and I even added in some buttresses.

So when it is pushed from the side, it is nice and stable, and it doesn't fall over.

I've even started to add on some green leaves to my beanstalk as well.

So can you get your tower ready, your beanstalk ready? Pop it down in front of you, get that pushing finger ready, and see if we can push it.

Does it fall over? It doesn't.

Try different centres of gravity.

Even at the top.

Try from a different way.

Amazing! So we have made a really stable beanstalk by widening the base.

Great job, everyone.

After the lesson, you might like to decorate yours just like a beanstalk too.

I'm going to carry on with mine.

Now, will you promise to keep your beanstalk safe for me? Make sure you keep it because we're going to need it in some of our other lessons.

Now, before you go, we've got an exit quiz question to do.

It's all about the learning that we have done today, so we're going to make sure that it is locked into our brains.

So here, I have made a tower, and to make it more stable, I have built something to help with that.

Now, have I built this tower a base or a buttress? Is it on a base or is it on a buttress? Have a few seconds to think.

Is this a base or have I used buttresses? Have a think.

You ready to tell me? Is it a base or a buttress? Tell me now.

Well done.

I have put it on a base.

So it's holding, I've attached my tower to the base.

Remember, a buttress is things that we put on the outside of our structure to help it to become more stable.

Well done, everybody.

Now, if you would like me to see your amazing beanstalks that you have done today, you can share your work with Oak National, and that means I will get to see them.

If you would like to, please ask your parent or carer to share your work on Instagram, Facebook, or Twitter, tagging @OakNational and #LearnwithOak.

Now, I can't wait to see you next lesson where we have more structures fun to do.

See you then, everybody.

Bye.