Hello and welcome to this design and technology lesson.

This lesson is called Aerodynamics and it's part of the Pulleys and Gears: Electric Vehicles unit.

My name's Mrs. Fletcher and I'm here to help and guide you through your learning today.

In today's lesson, we'll be looking at how aerodynamics is an important part of car design and how it involves looking at the shape of a vehicle.

And this can be an important part of making sure a car performs as well as possible.

So let's have a look at what we'll be learning about today.

The outcome of today's lesson is I can adapt a design to make it more effective, and this means we are going to be looking at an electric vehicle prototype and thinking about how we can change it in order to make it work more effectively.

There are some key words and phrases that we're going to need in today's lesson, so let's have a look at those together before we get started.

So first of all, we've got that word, "aerodynamics." So it's the name of the lesson, and it's the most important keyword we're going to look at today.

But what does it mean? Well, when we talk about aerodynamics, we're talking about the way air moves around an object.

In today's lesson, we'll be thinking about how air moves around vehicles and how it moves around cars.

And in particular, we'll be applying that to our electric vehicle prototypes.

Then we've got the word "body." In this lesson, we'll be referring to the body of a vehicle, and that's the main structure of a vehicle built onto a chassis.

And then we've got the word "performance," which is talking about how well something works.

And then we've got the word "drag," which means air pushing against a moving object.

So we'll be looking at how that relates to a vehicle and its performance.

Today's lesson is going to be split into two parts.

First of all, we'll be going to be looking at aerodynamics, what it is, and what it means, and then we'll be looking at how that will help us to shape a vehicle body to make it perform effectively.

So let's get started by looking at aerodynamics.

We might not be able to see the air around us, but it has a mass and it can be affected by objects in environment.

When objects move, they push the air in front of them and move it aside.

So to move through air, objects have to move that air that's in front of them to the side in order to get through.

And this creates what we call drag, which slows down moving objects.

The process of this happening is what we call aerodynamics.

So it's a whole science of looking at how air moves around objects.

That word itself, "aerodynamics," comes two parts there that we can look at.

We've got that first part, the word "aero," which comes from Greek origins and it means air.

And then we've got that second part, "dynamics" also comes from Greek origin, and that means a force or a power.

So when we put those two together to get the word "aerodynamics," we're talking about the force, which is the movement of air.

And vehicle aerodynamics, so when we are looking at it in relation to a vehicle, it's talking about how well a vehicle moves through the air and how the air moves around it.

So we are going to be looking at that specifically today.

A quick check then, what does that word "aerodynamic" mean? Does it mean the quality of the air? Does it mean the movement of air? or does it mean the visibility of air? Pause the video and have a think.

Welcome back.

How did you get on? Well done if you said it's the movement of airs.

Exactly, we are looking at how air moves around an object and how an object moves through air.

Well done if you got that right.

So that word "drag" that we came across before, it's talking about air resistance.

It's a type of frictional force that occurs between the air and the surface of a moving object.

It acts in the opposite direction to the way that the object is moving.

So if you think about that in terms of a car, if the car is moving in this direction, following that arrow there, the resistance is acting in the opposite direction.

So it's pushing against the car in the opposite direction.

That's because the car is trying to get through the air, the air is pushing against it.

So that's what we're talking about when we talk about drag.

Car designers have to consider the shape of the vehicle chassis and its body in order to reduce that drag and to improve its performance.

So we don't want a car to struggle to get through the air, we want it to be able to move through the air effectively so that it doesn't push it back.

So if you have a look at here, if the vehicle's moving in that direction and we had a body shape like this, there's a large surface there where the air pushing in the opposite direction can create that drag.

So we don't want that type of surface, flat vertical surfaces, stop air from getting past and that increases drag.

If we look at the shape of this vehicle body here, the vehicle's moving in the same direction, the air is pushing against it in the opposite direction, the size of that vertical surface has been reduced, and a sloping surface has been introduced.

And that's a better shape.

A curved slope surface allows that air to flow up and over the vehicle, which reduces the drag, and it means that the vehicle can move through the air more effectively.

Engineers can test a car's performance in relation to its drag using a wind chamber, which uses smoke to see and measure how the air moves around a vehicle.

And that works a little bit like this.

So you can see here, the vehicle in the chamber, sits in front of a large fan, which blows air at the vehicle in the way it would if it was moving outside.

And smoke is introduced so we they can see how the air is moving.

And they can see how it moves, where it stops, where it moves over the vehicle.

And that can help 'em to see how the vehicle shape performs in real life.

It's important to test the performance of a vehicle because the more drag a car has, so the more air stops in front of it, the more fuel the car has to use in order to push through that air, which means it costs more money to run.

A quick check then before we move on.

A car with little drag, so a very small amount of drag, will use more fuel.

Is that true or false? Pause video and have a think.

Welcome back.

What did you think? Well, it is false, but why is that? Well, that's because the engine of the car doesn't have to work as hard to push against the force of the air if there's only a little bit of drag.

So the more drag a vehicle has, the more fuel it uses.

So it's the opposite.

If we are using that has a little bit of drag, it's using a smaller amount of fuel.

Well done if you got that right.

Lucas and Sofia have been testing the aerodynamics of some paper aeroplanes.

This is another type of vehicle or another object that can move through the air.

Lucas has built himself this paper aeroplane, and Sofia has built herself this type of paper aeroplane.

Now, thinking about what we've already learned about aerodynamics and how objects move through the air, which paper aeroplane do you think has the best aerodynamics and will move more effectively through the air, and why? Pause the video while you discuss that with a partner or a group and then come back when you're done.

Welcome back.

So what did you think about Lucas and Sofia's paper aeroplanes ? Who do you think would have the most effective paper aeroplane when it comes to aerodynamics? Well, the sharp point at the front of Lucas's plane will help it cut through the air more effectively.

And the more blunt end of Sofia's will stop more air, which will increase that drag.

So it doesn't mean that Sofia's aeroplane won't work, it just means that she will have an increased amount of drag, which means it may slow down the speed at which the aeroplane can move through the air.

Well done if you managed to discuss that and came up with some similar points.

So it's time for a task in this first part of the lesson.

I would like you to fill in the missing words of these four sentences using the word bank at the bottom of the slide.

So the first sentence is aerodynamics is the way an object moves through, what? And then sentence number two, air pushing against an object creates, what? Sentence number three, air resistance moves in which direction compared to the object? And sentence number four, reducing drag reduces what and improves what? And the key words that you'll need to include in there are "opposite," "air," "performance," "fuel consumption," and "drag." Can you put those in the correct place? Pause the video while you have a go at that task and come back when you're done.

Welcome back.

How did you get on? Well, let's have a look at those sentences.

So sentence number one, aerodynamics is the way an object moves through air.

So the missing word was "air" there.

Sentence number two, air pushing against an object creates drag.

So that was the missing word in sentence two.

Sentence number three, air resistance moves in the opposite direction to the object.

And sentence number four, reducing drag reduces fuel consumption and it improves performance.

So check your answers against those sentences.

Well done if you manage to get them all in the correct place.

Time for the second part of the lesson now, and this is where we'll be looking at how we can use that information about aerodynamics to help us create the shape of our vehicle body.

Now we have some knowledge about aerodynamics.

We can apply this to design a body for a prototype electric vehicle.

The body of the vehicle is the outer shell that sits on top of the chassis.

So we can see here the chassis at the bottom, which is where we have the wheels.

And then we've got the body that sits on top, and that's the part we're going to be concentrating on now.

The shape must allow the air to flow easily allowing the car to have a better performance and move more efficiently.

So we can see here with this shape of this vehicle allows air to move up and over the vehicle in a smooth way.

It doesn't get stopped against a vertical flat surface.

And that's what we learned in that first part of the lesson, that those sloping surfaces are much better for aerodynamics than those for flat vertical surfaces which stop the air.

The body shape can be made in parts and joined together, or we can make it in one piece and fold it and cut it to shape.

So we can see here this vehicle body has been made by cutting out two side pieces and a piece that will attach to the top.

And then those have been joined together to make the vehicle body.

On this vehicle, one piece of card was marked and cut out to fold into shape.

So you can see here we've got the different parts of the vehicle, but they're all together, a bit like a net.

And you can see the places where it's been cut off, folded to create the top, the front, the sides, and the back of the vehicle.

So that's a little bit of a trickier method, but it can mean you can just use one piece of car to create your body.

Before we move on though, let's just have a quick check at what Lucas and Sofia have been discussing.

Who is describing vehicle aerodynamics correctly? Let's see what they're saying.

So Lucas is saying the shape of the vehicle needs to let air flow over it easily without stopping it.

Vertical flat surfaces will stop the air flowing.

And Sofia is saying that the shape of the vehicle needs to stop air from moving freely, and curved surfaces create more drag.

Who is describing vehicle aerodynamics correctly? Pause the video and have a think.

Welcome back.

What did you think? Well done if you said Lucas is describing the vehicle aerodynamics correctly.

He is, exactly, he's talking about the shape, being able to allow the air to flow over it without stopping it, and that those flat vertical surfaces stop the air from doing that.

And that is exactly what we need when we are thinking about a vehicle shape.

Well done if you got that right.

So let's think about the materials that we're going to use to make the body of our prototype electric vehicle.

So we're not thinking about an actual vehicle and the materials that will be used for that, we are thinking about our prototype and the materials we can use to add a body onto that.

So any material we use will need to be lightweight, and that's to reduce the overall weight of the vehicle and allow the motor to move the vehicle effectively.

So if it's too heavy, then the motor that we attach is going to struggle to move our vehicle along.

The material also needs to be easy to shape so that we can create those different shapes of vehicle body that we want to, and it will allow us to change it and adapt it quite easily if we need to.

So if it's not working, we can easily change it.

So there we can see that vehicle body has been made from some thin car, which is easy to cut, easy to fold, and easy to change the shape of if we make any mistakes or we want to adapt or change it to work in a different way.

the body should then be joined securely to the vehicle chassis.

So if the body's not been joined to the chassis, then it's not going to stay attached when the vehicle moves.

We could use double-sided tape, we could use masking tape, we could use different types of glue to do this, they're all good ways that we can adjoin the vehicle, and particularly if we are using something like a thin car to make our body, all of those joining techniques would work really well.

Remember though, when we make our vehicle body, we need to leave access to the electrical circuit inside.

So if we can't get to that circuit, then we can't turn it on in order to make our vehicles move.

So we need to make sure we keep at least one access point to the inside of the vehicle.

A quick check then before we move on, which these vehicle shapes would have the least drag? So they're all travelling in the same direction, but have a look carefully at the airflow and what the way it's moving around the vehicle.

Which would create the least amount of drag? Pause the video and have a think.

Welcome back.

What did you think? Well done if you said C.

So if we look at the airflow of A, it's hitting a vertical flat surface, which will create a large amount of drag.

If we look at the middle one, vehicle B, the air is flowing up a sloped surface, but then it hits a vertical surface, flat surface there.

So it might have slightly better aerodynamics than vehicle A, but it still has some resistance there.

But if we look at vehicle C, the air can flow straight over that sloped surface.

It doesn't hit any flat vertical surfaces, so that would have the least amount of drag.

Well done if you got that right.

So that leads us to the final task in this lesson.

This is where you get to create a body for your prototype vehicle.

So first of all, I'd like you to sketch down some ideas for the type of body you would like to make for your electric vehicle.

I'd like you to think about what shape it's going to be, and that means we need to consider those aerodynamics.

We don't want any flat vertical surfaces or we want to keep those to a minimum.

Want to make sure we have lots of smooth, sloped, or curved surfaces that allow the air to move over it.

I want you to think about what type of material you're going to use to make it from.

Remember, we want to keep it lightweight and be able to adapt it if we need to.

And I want you to think about how you're going to join your body onto your chassis.

So thinking about where it can join and what type of joining material you'll use to do that.

Pause the video while you complete that task and come back when you're done.

Welcome back.

How did you get on? You should have a few different ideas now for different body shapes that you could use for your vehicle.

So for the second part of the task, I would like you to choose one of your designs, and you're going to make it.

So you'll need to decide whether you make it in separate parts or as one piece that's folded and cut into the right shape for your vehicle.

You may need to do some measuring in order to make that work.

And I want you to use the material that you think would be best for this job and the joining method that will attach your body to your chassis as well.

Pause the video while you complete that task and come back when you're done.

Welcome back.

So hopefully you've managed to build a vehicle body out of a suitable material and attach it or join it to the chassis of your prototype electric vehicle.

For the final part of your task, I would like you to review the vehicle shape that you have made.

Do you need to make any adjustments? Is there any way you can make it more aerodynamic so that we can reduce the amount of drag that will be acting on your car which will increase its performance? Look at the different sides of your vehicle, see if there's any way you can make any adjustments.

If you don't need to, then well done, you have finished your task.

Otherwise, you can make those adjustments to your vehicle now.

Pause the video while you have a look at your vehicle and come back when you're done.

Welcome back.

How did you get on? Well, reviewing your vehicle gives you a chance to make sure you have made it as effective as possible.

So you should make sure that it's made from a lightweight material that is going to reduce the weight of your overall vehicle, that it has a good aerodynamic shape.

So that means we've got sloping curves or sloping flat surfaces.

We've got no vertical flat surfaces, which will stop that air from getting past the vehicle quickly, and that will improve the performance.

And we should make sure that the vehicle body that you have made is securely attached onto the chassis so that it doesn't, it's not going to come off when the vehicle starts to move.

Well done if you managed to complete that task.

We have come to the end of the lesson now.

So we've learned lots today about aerodynamics and how they are so important to the design of vehicles.

And we've even got to put that into practise by designing the shape of our own vehicle bodies.

We've learned that the body of a vehicle is the outer shell which sits on top of the chassis.

We've learned that aerodynamics reduces drag and fuel consumption.

So having that correct shape reduces those two things.

And we know that car designers must test and consider the chassis and the body of the car in order to get the best performance from the vehicle that they are designing.

And the car body design needs to be shaped to consider those aerodynamics when it is being designed.

Thank you for joining me for this lesson today.

We've learned lots together, and I hope to see you again in another lesson in the future, but it's goodbye for now.

Goodbye.