Hello, my name is Mrs. Mehrin and I am so excited to be learning all about choosing and using electrical conductors and insulators.

Let's begin.

Welcome to today's lesson from the unit Changing circuits.

Your lesson outcome today is: I can explain the difference between electrical conductors and insulators and can identify where each type of material should be used.

Now, we are going to be touching upon some of your previous learning all about circuits, and that's really going to help us with today's lesson.

Now, I know that learning can sometimes be a little bit challenging, but that's okay, because it just means that we are going to work really hard together and we are going to learn some fabulous new things.

Let's begin.

Here are your four keywords for today's lesson.

Now, you don't need to write these down because I am going to be referring to these words throughout today's lesson, and you will see them appear in bold as we go through the lesson.

Now, if it makes it easier for you, you can pause the video here and you can jot them down if that makes it easy.

So you can pop the video on pause now and have a go at doing that.

Fantastic, well done.

And here are the definitions for those four keywords.

Again, I'm going to be referring to these throughout today's video, but if it helps you, you can pause the video now and jot them down.

Fantastic, well done.

Now let's begin with the first part of your lesson, conductors and insulators.

Now, for electrical circuits to work, electricity must be able to flow around them.

And Aisha says, "I know that some materials allow electricity to pass through them easily and some do not.

What are the names of each of these types of materials?" I'll give you five seconds to think about your answer.

Off you go.

Fantastic, well done.

So you have an electrical conductor, and this is a material that allows electricity to pass through it easily.

And you have an electrical insulator, which is a material that does not allow electricity to pass through it easily.

Now, Lucas says, "I can't remember which materials are electrical conductors and which are electrical insulators." Now, how could you test whether something is an electrical insulator or an electrical conductor? I'll give you five seconds to think about your answer.

Off you go.

Fantastic, well done.

So, Lucas checks his simple circuit works first, and we can see the simple circuit here, and then he adds different materials to the circuit one at a time to test which ones are electrical conductors.

Now, if the material is an electrical conductor, then the buzzer is going to buzz.

So just like this here.

So we've got the cell, got our battery there, the cell, the single cell we have here.

We've got the wires all connected up to the buzzer just like you would have in a simple circuit.

However, you have a conductor right there in the middle of this circuit.

And if the buzzer still buzzes, it means that the material that you've used there is a conductor.

It means that it allows electricity to flow through it.

Now, electricity will be able to pass through the conductor, completing the circuit.

Now, if the material is an electrical insulator, the buzzer is not going to buzz.

So what's really important here is that you actually just test your simple circuit first without a conductor or an insulator to ensure that everything is working in the circuit first to really make sure that you are identifying the electrical insulators correctly.

So what you'll have here is no sound at all.

If you put an insulator there, it's going to be an incomplete circuit, because you've got something that is stopping the electricity from flowing through.

So electricity is not going to be able to pass through the insulator.

It's going to create a gap and make the circuit incomplete, which means that the buzzer is not going to sound.

Now, which of the following types of materials allow electricity to pass through them easily? Is it A, electrical conveyors, B, electrical convectors, or C, electrical conductors? I'll give you five seconds to think about your answer.

Off you go.

Fantastic, well done.

The answer is C, electrical conductors.

True or false, electrical insulators allow electricity to pass through them easily.

Is that true or is that false? I'll give you five seconds to think about your answer.

Off you go.

Fabulous, well done.

The answer is false.

Now let's see if you can justify your answer.

Is that because electrical insulators do not allow electricity to pass through them easily or because electrical conductors do not allow electricity to pass through them easily? I'll give you five seconds to think about your answer.

Off you go.

Fantastic, well done.

The answer is A, electrical insulators do not allow electricity to pass through them easily.

However, an electrical conductor does.

Now we are onto your first task.

Aisha says that she thinks metals are the best electrical conductors.

Alex says, "I disagree.

Only non-metals conduct electricity." And Lucas said, "Only metal conducts electricity." So, who do you agree with and why? So what you could do here is you could use Lucas' circuit, so creating a really simple circuit and then adding some metals and non-metals to the circuit to see whether or not they conduct electricity and to see who is correct and who is incorrect.

So, I want you to pause the video here and I want you to have a go at that activity.

Off you go.

Fantastic, well done.

So Aisha is correct.

Metals are the best electrical conductors.

Now, we are going to have a deeper look into this now and we're going to be starting on the next part of our lesson, which is choosing the right materials.

Now, all metals are electrical conductors, but some metals are better conductors than others.

So here we have a picture of a pylon and we have electricity cables supported by the pylon.

And a pylon is a tall structure made of steel used for carrying electricity cables high above the ground, and we often see pylons in the countrysides or somewhere where there's a lot of space.

So next time you're in the countryside and you're driving through or walking through, you may be able to spot these pylons.

Now, the cables are made from aluminium and steel, which are good electrical conductors.

Now, because they are good electrical conductors, it means that electricity will be flowing through them.

So it's really, really important that you don't get too close to these pylons because they are very dangerous and can electrocute people.

Now, we also need electrical insulators too.

So electrical insulators help keep us safe from the dangerous effects of electricity flowing through conductors, just like I've told you.

Now, to avoid the metal cables conducting electricity into the steel pylons, insulators are made from porcelain, toughened glass, or rubber, and are used to attach the cables to the pylon.

So which materials are often used to make electrical wires? So I want you to think really carefully about this question.

I'll give you five seconds, but if you need longer, you can pause the video here.

Off you go.

Fantastic, well done.

So copper is a really good electrical conductor, which is why it's often used to make wires for electrical circuits.

And to help keep us safe from electrical shocks, wires are covered by electrical insulators made from plastic or rubber.

So here we have copper wires in plastic casing.

Not all non-metals are electrical insulators, however.

So water is not a good insulator because there are sometimes minerals dissolved into it, which are electrical conductors.

And materials made from electrical insulators help keep us safe from electrical shocks when using electrical appliances that involve water.

So can you think of any electrical appliances that might use water? I'll give you five seconds to think about your answer.

Fantastic, well done.

So you may have thought of a kettle, for example, which is an electrical appliance and uses water.

Now, let's do this question.

It says, how can electrical insulators help protect us from electric shocks? A, they keep us warm, B, they can keep us safe from the dangerous effects of electricity, or C, they can reduce the force needed to do the work.

I'll give you five seconds to think about your answer.

Off you go.

Fantastic, well done.

The answer is B, they can keep us safe from the dangerous effects of electricity.

Now, scientists and engineers need to choose the materials to make electrical appliances carefully to help keep us safe from electric shocks.

And they must use the right electrical conductor to make the equipment work, but also choose the best electrical insulator to help keep us safe when using it.

So here we've got assembling plastic coated electrical equipment in a factory.

So I'm thinking straight away, for example, to an iPad charger or a mobile phone charger.

So those are electrical wires inside them, but they have a rubber casing or a plastic casing around it, because the plastic and the rubber are great insulators so you're not going to hurt yourself every time you're going to plug in your iPad or your phone.

Now, engineers design electrical appliances so that they can be used safely without giving us electric shocks, just like I've spoken about.

So Lucas says, "I'm not sure which parts of the electrical appliances need to be good conductors and which need to be insulators." Now, do you think you can help Lucas? Have a look at this picture.

You can pause the video here if you need to.

And just think, right, which parts need to be good conductors in order for the blender to work, but which need to be good insulators in order to protect us? So, I'll give you five seconds, but if you need to, you can pause the video here and have a go.

Off you go.

Fantastic, well done.

So, we have a circuit which is inside that casing at the bottom, and it's inside that casing and it will protect us because the casing is plastic.

We have the switch, we've got the cable to the plug, the handle, and the lid.

Now, the electricity must be able to pass through the components in the circuit and the cable that leads to the plug and the mains electricity.

Now, the electricity must not pass through the parts we touch or which water touches.

So here we've got the lid, which is an insulator, because again, that water that's inside the blender may touch the lid.

So we don't want that to be a conductor.

The handle is an insulator as well.

We need to be able to hold the handle.

If that's a conductor, we could get electrocuted.

The jug is an insulator, the casing is an insulator, and the wires for the cable are inside an insulating case.

And the switch as well, which we're going to be using our hands on, that's an insulator on the outside, the conductor is on the inside, so it protects us.

Now, Lucas wants to apply his understanding of insulators and conductors to design and make a buzz-wire game like the one in the picture here.

He has to carefully move a loop from one end of a wobbly wire to the other without touching the wire.

And if the loop touches the wire, a buzzer will make a noise to alert you that you've touched it.

Now, Lucas knows that he has to choose different materials to solve this problem.

He says, "I should make the buzz-wire game using only electrical conductors, because the loop and the wobbly wire need to connect to complete the circuit and make the buzzer." What do you think? I'll give you five seconds to think about your answer.

Off you go.

Well done.

So we will come back to that in a moment.

Now, how do engineers use their knowledge of insulators and conductors? Is it A, they sell electrical appliances in shops, B, they set up investigations to find out which materials are transparent, or C, they choose the right materials to solve problems involving electrical equipment? So I will give you five seconds to think about your answer.

Off you go.

Fantastic, well done.

The answer is C.

They choose the right materials to solve problems involving electrical equipment.

Now here is Task B.

It says, use your knowledge of insulators and conductors to design and build a buzz-wire game.

I want you to draw and label a diagram to show which parts of the game should be made using an insulator and which should be made using a conductor, including the stand, the wobbly wire, the loop and loop holder, and where to connect your simple circuit.

Then I want you to build the game, test it, and then explain how it works.

So, you are going to need to pause the video here, you're going to have to take some time to do this, and then we will carry on the lesson once all of these activities have been completed.

Off you go.

Fantastic, well done.

So, here we have an example of one.

So we've got a wire frame made of metal to conduct electricity so that every single time that wire loop that's made of metal to conduct electricity, every time it touches it, the buzzer goes off.

The wire has been pushed through the stand to fix it in place.

And we have a metal wire to conduct electricity, we have the cell, we've got polystyrene packaging stand, which is an insulator to support the metal frame, a handle, a plastic spoon taped to a metal wire made of insulator to protect the user.

Remember, Lucas wanted to make the entire thing out of metal, but actually that would've been very unsafe.

Then it's been made and it's been tested.

So my simple circuit is connected to the wire loop and also to the wobbly wire frame, which are both electrical conductors.

When the wire loop makes contact and touches the wire frame, this completes the circuit and the buzzer will buzz.

Now we are on to our summary for today.

An electrical conductor is a material that allows electricity to pass through it easily.

An electrical insulator is a material that does not allow electricity to pass through it easily.

Electrical insulators keep us safe from the dangerous effects of electricity flowing through conductors.

Scientists and engineers chose conductors and insulators to solve problems. I am so proud of your learning today.

You have worked absolutely brilliantly and have tried your very best.

Well done.