Hello, and welcome to today's Design and Technology lesson.

My name is Mrs. Fletcher, and I'm here to help and guide you through this lesson today.

Today's lesson is called Add a Switch to a Design, and it's part of the Pulleys and Gears Electric Vehicles Unit.

In this lesson we'll be looking at how to add a switch to an electric circuit, and we'll be using that to add to our prototype electric vehicles so that we're able to turn the power on and off.

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

The outcome of today's lesson is I can add a switch to a vehicle body.

So that means we are looking at how to add the switch to the electric circuit that we've already created and how we can attach that to the body of the vehicle so that we can access that in order to power and stop the vehicle that we've made.

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

First of all, we've got the word switch.

So what do we mean when we talk about a switch? Well, we're talking about a device that controls the flow of electricity by completing or breaking a circuit.

So we're going to be looking at how that works today.

And then we've got the word insulating, and that's talking about anything that does not allow heat or electricity to pass through it.

So that will be an important part of today's lesson as well.

And then we've got the word connection, and that means where two things meet and touch.

So now we've got the words that we need.

Let's have a look at how the lesson will be broken down today.

There are two parts to today's lesson.

First of all, we're going to be looking at electrical safety and particularly how to secure wires to make sure our electrical circuits on our vehicles are safe.

And then we'll be looking at connecting the electric components of our electric vehicle.

So let's get started with electrical safety.

It is very important to stay safe when we are working with any type of electrical equipment.

Even simple circuits like the ones that we're going to be using today can be hazardous if we don't follow a few simple safety rules.

Cells and batteries are part of the electric circuits that we're going to be using today.

So let's have a look at how we can stay safe when we use those.

Cells and batteries can be very dangerous and they may give an electric shock, especially if the circuit is not connected correctly.

So it's very important that we follow the steps to connect our circuits today.

We also need to make sure that we don't have any water anywhere near our electrical circuits.

It's very dangerous to have water near an electrical circuit.

Water and electricity do not mix.

Sometimes cells and batteries can get old or they may not have been stored correctly, and this can cause them to leak.

And the fluid that leaks from a battery, it can be quite dangerous.

It can burn your skin.

So we need to make sure we are looking out for any batteries that don't appear to be in good condition.

A short circuit is what we call it when the positive and negative terminals or ends of a cell or battery are directly connected or touching each other.

This can be dangerous because the cells are batteries can overheat.

If that happens, the components that are attached to the batteries such as the wires can melt because of that overheating, and dangerous fumes can come out of the components which are dangerous for us to breathe in.

You could also get a burn as well because of that overheating and possible fire risk from the wires as well.

So to make sure we stay safe when we're using cells and batteries, we should use zinc-carbon cells.

They're often used in schools anyway because they're less likely to short-circuit or to get too hot if they do accidentally get connected incorrectly.

If the cell looks damaged, we need to make sure that you report it to somebody and don't touch it so that it can be dealt with and removed.

You need to make sure you keep the water away from the circuit and the cells, and you need to make sure that you connect the battery pack last when you're making the circuit.

So if we put everything in place first and then add the battery, then we can make sure that it's going to work correctly and not short-circuit.

And the opposite then is true.

When we are finished with our circuits, we take the battery pack out first.

We disconnect that from the circuit when we are finished so that we don't accidentally short-circuit that battery.

Always make sure that you follow your teacher or adult's instructions carefully when you are working with any type of electrical components or electrical circuits.

A quick check then before we move on, when should the battery pack be connected to the circuit? Should it be connected last second or first? Pause video and have a think.

Welcome back.

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

So we need to make sure we've got everything in place before we connect that battery pack because that is where the power is going to come from.

So we need to make sure that the power is going to go to the right place and not short-circuit.

Well done if you got that correct.

To make our circuit safe, we need to cover the bare wires and connections, and we use a special type of electrical tape to do this, which is made from an insulating material just like the cover on the wires that we use in a circuit.

Any exposed or bare metal in the circuit should be covered with the tape to insulate it.

And that word insulate means it's going to keep any electrical current that's passing through those bare wires, or that bare metal inside and not let it be exposed to us, so to get an electric shock or to any other wires which would cause it to short-circuit.

So there's an insulated connection that's been covered with that insulating tape, and there's the exposed connection which doesn't have any tape on it and that's where the risk would come.

Quick check then, true or false, electrical tape is an insulator.

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

Welcome back.

What did you think? Well done if you said it was true.

It is true, but why? Well, the tape is used to cover metal, which is a conductor.

That means it allows electricity to pass through it, and the material that the tape is made from stops electricity from passing through it.

And materials that do not allow electricity to pass through are called insulators.

So well done if you got that right.

Time for the first task in this part of the lesson.

I would like you to discuss the methods of keeping safe when using electricity and electrical circuits either with your partner or a group.

And then I want you to write down the top three tips for staying safe.

So we went through quite a few tips there for staying safe, but which ones do you think are the most important ones that we need to remember? So choose your top three tips and make a note of those.

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

Welcome back.

How did you get on? Well, Andeep has been discussing those electrical safety tips with his partner.

He's chosen his top three tips.

Let's have a look at which ones he's chosen.

So first of all, he's chosen, keep everything away from water, which includes making sure your hands are dry.

That's his main top tip number one.

Then he's chosen, report any damaged equipment.

That certainly is important.

That means that we can stay safe by not touching that equipment and reporting it to an adult.

And his third one is to insulate those exposed wires and connections using electrical tape.

Well done, Andeep.

That is very important.

Those will all reduce the risk to us.

And he's saying there that one of the biggest risks when using electricity is getting a shock.

And that is very true, that electricity can give us a shock if we are exposed to it.

And these tips that he's chosen reduce the risk and help us stay safe.

So well done.

Those are the reasons Andeep chose his three tips.

Hopefully you've chosen your three tips for similar reasons with the aim to keep us safe.

Well done on completing that task.

So it's time for the second part of the lesson now, and this is where we'll be connecting our electrical components to our prototype electric vehicles.

To make a prototype electric vehicle move, we need a complete electrical circuit, including the switch.

The switch is the important part today, but we need the whole circuit to make it work.

So here we can see on our vehicle, there's no body on this vehicle.

We're looking inside.

We can see the motor which will turn that pulley.

We can see the switch there, which is going to allow us to stop and start the circuit, open and close that circuit.

We can see the wires that connect all the components together, and we can see the battery pack including the cells which will be connected to the circuit to power that motor.

That will be the last thing we connect to our circuit today.

In an electrical circuit, switches are a type of input, and that's because they can change the circuit.

Switches connect the circuit to make it work, or they can create a break in the circuit to stop it from working, and that's how it can allow us to stop and start our electric vehicle.

So here we can see in this circuit diagram, if we have an open switch, that means we've got a broken circuit, which means there's no power going to our vehicle, so nothing in the circuit is moving so the vehicle won't move.

Once we close that switch, we complete the circuit, which means the electricity can flow and it will power the motor, which will turn the pulley and make the vehicle move as we can see there.

So the switch is important parts of our electrical circuit.

A quick check then, why is a switch considered an input in a circuit? Is it because it powers the circuit? Is it because it responds to a connected circuit, or is it because it changes the circuit? Pause the video and have a think.

Welcome back.

What did you think? Well done if you said it's because it changes the circuit.

So anything that's an input to the circuit is going to change something about it.

An output, which is the opposite, is what happens once the circuit is connected.

So a switch is an input because it's what we need to do to cause a change or something we need to move in order to cause the change.

Well done if you got that right.

The switch can be added directly to the chassis or body of your electric vehicle so that it stays in one place or it can be made separately, which means it can then be moved or attached anywhere on the body.

Here we have that first method where it's the switch is part of the chassis so it can't move.

That's it's gonna stay in that place and all the components will stay in the same place.

And then method two is where we make the switch on a separate piece of card, which means we can change the position of that switch.

So we might be able to test it out in a few different places.

We'll still have the same circuit as we've got in method one, but the switch will be movable.

So let's go through the steps for each of those methods and then you can decide which one you're going to use to make the switch for your prototype electric vehicle.

So method number one, these are the steps to add the switch to the chassis or to one of the main parts of the body.

So to do this, the first step you'll need is to place a paperclip in the position where you want your switch to be and make sure it's not sitting on the wooden frame or anything that you can't pierce through because you're going to need to pierce through the chassis or the body to make a connection on the back.

So make sure you're not on top of anything that can't be pierced.

So make sure on top of the card is a good place to place it.

Once you've got the paperclip in position, step number two is to mark each end.

So use a pencil to mark inside the paperclip at each end as you can see in that first image there.

Then you're going to use a sharp pencil to safely pierce through holes where you've made those marks.

And when we say to do it safely, we mean to take a piece of sticky tack, a ball of sticky tack, put it underneath the card so when you push through your pencil, it pushes into that sticky tack and doesn't poke into your finger or onto the table.

So that's the safe way of piercing the hole.

Once you've got your two holes, you're going to push a split pin through each hole, making sure that one of them has been pushed through the paperclip as well.

So you can see in that third image there, got two split pins push through the card.

One of them has gone through the paperclip, and that's to keep that paperclip in place.

We don't want both ends to be permanently attached to the clips.

We just want one end.

And then turn your vehicle over and open up the backs of those split pins as you can see in that final image there.

And that's why you need to make sure you do it just on the cardboard part of your chassis or body because you need to be able to get through and open those pins on the other side.

So you should have those two split pins in position with one of them going through the paperclip.

That leads us to step number three.

So here you're going to take one of the wires from your battery pack, which should be attached to your chassis but not have any cells in it.

And you're going to loop the bare wire that's on the end of that and attach it to the split pin on the underneath of your chassis or body where we've just positioned it.

So you can see there in the image, we take it from the switch and we attach it to the back of that split pin and you'll need to bend the slip pin over to hold that loop of metal in place.

So we've got a good connection there meeting and touching really well.

Then you're going to cover that connection with electrical tape, and that's to make it safe.

So we've not got any electricity exposed coming through that connection there.

It might be necessary to remove the axle and wheels here if they're in your way.

Depends where you've positioned your switch, but you can take the wheel and axle off if it's in the way.

Then you're going to use a wire stripper to remove the insulation off both ends of a sharp length of wire, so you're getting a separate piece of wire now.

Use those wire strippers and you may need an adult to help you with this or to show you how to use them.

This removes the insulation from the wire and exposes the metal.

We need that metal to be exposed so we can connect it to the metal of the next component.

You're going to loop the end just like we did with the previous wire and you're going to attach it to the second split pin.

So this will be connected just to the split pin at this point.

Then you're going to cover that connection with a piece of electrical tape as well.

You need to make sure that that piece of wire that you've attached will reach around from the split pin to the motor because you're going to attach it to the motor.

So it needs to be long enough to reach the position of your motor.

So check that before you connect it.

Step five, then you're going to loop the other end of that length of wire and secure it onto the motor connection.

So again, you're going to bend that loop around the metal connector of the motor as you can see there in that image, and then you're going to loop and attach the second wire that's coming from the battery pack in the same way onto the second motor connection.

So this has created our circuit.

We should have a wire that connects from the battery pack to the motor, one that connects from the motor to the split pin, which will be the switch, one that connects from the split pin back to the battery.

So that will complete our circuit.

So make sure you've got all those things in place.

Then you're going to cover those two electrical connections of the motor with that electrical tape to make sure we've made that connection safe as well.

And for the final couple of steps, we are going to replace the wheels and axles if you needed to remove them to get access to the switch.

And then you're going to add the two zinc-carbon cells into the battery pack.

Once you've done that, you can slide that paperclip to close the switch.

So by connecting the paperclip to the second split pin, you're completing that circuit which will allow the power from those cells to flow around the circuit and power that motor which is attached to that pulley and the pulley is attached to the wheels, so it should allow those wheels to rotate.

Check that that is all working correctly.

If it's not, then we need to look at each part of those steps again and make sure we've connected everything in the correct place.

A quick check then before we move on, why do we need to strip the installation off a wire before we connect it? Is it to make it easier to bend? Is it to allow the circuit to connect, or is it to stop it making a connection? Pause the video and have a think.

Welcome back.

What did you think? Well done if you said it was to allow the circuit to connect.

So by having those bare pieces of metal, which are conductors, allows them to touch, that allows us to connect that circuit to power it.

Well done if you got that right.

So let's move on to looking at method two.

So the switch components can be attached to a separate piece of card or to the car body or to a section of the car body and then connected in the same way to the motor and the cells.

This allows the switch to be placed anywhere on the vehicle body, which makes it easier to access.

So this can make it easier to switch that switch on and off, particularly if you've not got much access to the inside of your electric vehicle.

So these are the resources we're going to need in order to make a separate switch.

We're going to need some scissors, a pencil, some sticky tack, some split pins, a small piece of card and a paperclip.

So these are the steps to make a separate switch.

So you're going to take the piece of card that you're going to use to make your switch, place the paperclip in the position in the centre of that card and mark out at either end where the split pins are going to go.

And then you're going to use the same method we discussed earlier on to safely pierce holes in that card.

So by putting a piece of sticky tack underneath, we can safely pierce those holes in the card.

Once you've done that, you're going to attach those split pins through the holes, making sure one of them goes through the paperclip as well.

So look at the image there.

You can see one split pin has been pushed through the paperclip to hold it in place and then one of them has been pushed through that's, and it's not connected to the paperclip.

So make sure we've got both of those in place.

Then we need to turn over the piece of card and open out the back of the slip pins to keep them in place.

Now look at those two images there.

We need to make sure that the slip pins are not touching.

That's what we want it to look like.

That first image.

We don't want them to be touching because that will change our electrical circuit.

So we need them to be separate.

So make sure it looks like that first image.

Then you're going to go back and follow steps three to eight of method one.

So you've got that switch on a separate piece of card, and you're going to connect it in exactly the same way to the battery pack and to the motor insulating those exposed connections as you go.

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

So you're going to follow the steps to add a switch to your vehicle, either using method one where you add and connect a switch to the chassis or body directly onto your vehicle, or method two where you make a separate switch on a piece of card to attach anywhere you want on the vehicle.

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

Welcome back.

How did you get on? Well, Andeep has chosen to add a switch to the chassis of his vehicle.

So was method one.

He's saying here that the circuit is hidden but he can reach the switch through the back of his vehicle.

So he chose to add it to the chassis because he had access to that part of the vehicle through the back of the body.

So that's where he wanted it to go, whereas Laura has made a separate switch on a piece of card and she's attached that to the outside of her vehicle body.

The reason she's saying is because the switch is easier to reach, and that's especially important because the car starts as soon as you slide that switch into position because as soon as you make that connection, those components start to move and the vehicle will start to move.

So that having the switch on the outside means she can move her hand out of the way much quicker.

So they've both got different reasons for choosing which method they used.

You should have chosen one of those methods and you should now have a working switch on your prototype electric vehicle.

Well done if you've managed to complete that task.

We are at the end of the lesson now.

We've had fun today looking at how a switch works and how we can attach it to our prototype electric vehicles to make them work.

We've learned that the slide switch, which is a type of switch we've used today, needs to be added to an electrical system in order to make it work.

We've learned that the battery packs need to be attached last and those connections secured in order to make it safe.

And we've learned that bare wires can be secured and made safe using that insulating electrical tape.

So all important steps to making our electrical circuit safe.

Thank you for joining me for this lesson today.

Well done on making your prototype electric vehicles.

I hope to see you again soon.

Goodbye.