Lesson video

Hello, my name is Mrs. Mehrin.

And I'm so excited to be learning all about how electrical insulators keep us safe.

Let's begin.

Welcome to your lesson from the unit, Changing circuits.

Your lesson outcome is, I can identify how electrical insulators keep us safe.

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 lots of fabulous new things.

Let's begin.

So let's start off with your five keywords for today.

Now, I am going to be referring to these keywords throughout today's lesson.

However, if you find that it is helpful for you to have them written down, you can pause the video here and jot those down now.

Fabulous, well done.

And here are the definitions for those keywords.

Again, I am going to refer to these throughout the lesson, but if you find it helpful to have these written down, you can pause the video now and jot these down.

Off you go.

Fantastic, well done.

So our lesson today is put into three parts.

Let's begin with the first one.

Insulators protect people working with electricity.

Now, electricity is essential in our modern lives.

We use it all the time.

Now, can you think of any other ways we rely on electricity apart from just lighting and technology? I'll give you five seconds to think about your answer.

Off you go.

Fantastic, well done.

So you might have thought about things such as heating, for example, if you have electrical heaters or fans that might use electricity, things like that.

Now, as much as we've come to rely on it, electricity can be very dangerous if we come in direct contact with it.

Now, if electricity passes into our bodies, an electric shock can occur.

This can make us very unwell and can even kill us.

People who work in some jobs risk electric shocks with exposure to high voltage electricity.

Now, can you think of any jobs like this? I'll give you five seconds to think about your answer.

Off you go.

Fabulous, well done.

So jobs such as power plant workers, line workers, and electricians all risk exposure to high voltage electricity.

And personal protective equipment, or PPE, is the name given to the safety items people wear to protect them and keep them safe in their work.

Now, what sort of materials do you think are used to make the PPE? So you're thinking about materials that are going to keep them safe whilst they are working around electricity.

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

Brilliant, well done.

So materials, which are good electrical insulators are usually used to make safety items. Now, can you name some suitable materials that are electrical insulators? Again, I'll give you five seconds to think about your answer.

You may have thought of these or you may have thought of some already, but I'll give you some more time to see if you can think of any others.

Off you go.

So plastic, rubber, ceramic, and glass are all insulators.

Now, line workers instal and maintain the wires that carry electricity around the country.

So as well as being exposed to high voltage electricity, they often work in high, awkward places, up pylons or poles, just like these line workers in the picture here.

Now, what sort of personal protection equipment, or PPE, can you see the line workers using in this picture? I'll give you five seconds to think about your answer, but if you need longer, you can pause the video and come back once you have your answers.

Off you go.

Fabulous, well done.

So maybe a safety harness, which will protect them from falling while they're working at height.

A hard hat provides protection from falling objects and head injuries.

Now, gloves that are made from rubber, which is an electrical insulator, protects them from electric shocks and burns.

And safety boots are also made from insulating materials.

Now, many of the tools that people working with electricity use are made from metal, which is an electrical conductor.

And Izzy says, why doesn't the electricity travel from the wires, through the tools, to line workers and electricians? What do you think? I'll give you five seconds to think about your answer.

Off you go.

So screwdrivers and other tools have handles that are made from electrical insulators.

So although the screwdriver, the part that they're going to be using, is metal, the part that they're holding onto, which is the handles, are made from electrical insulators.

And workers use voltage testers to check whether electricity is present before touching wires or equipment.

Now, electrical pylons and poles, used to support the cables that transport electricity, also have built-in safety protection.

Now, spacers made from good insulating materials separate the electrical cables from the structures that are supporting them.

So here, you can see the insulators.

Now these prevent high voltage electricity from being conducted into the pylons and poles, so workers can safely attach themselves to the structure to carry out maintenance.

Let's do a quick check-in of your learning so far.

So what risks are electricians, line workers, and power plant workers exposed to in their work? Is it a, high noise levels, b, high voltage electricity, or c, high temperature ovens? I'll give you five seconds to think about your answer.

Off you go.

Fabulous, well done.

The answer is b, high voltage electricity.

Now, what is the name of the safety wear used for work? Is a, personal protective equipment, PPE, b, personal safety equipment, PSE, or c, personal insulation equipment, PIE.

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

Off you go.

Fantastic, well done.

The answer is a.

Now here is your first task for today.

It says, annotate this drawing of a line worker to explain how their PPE protects them.

I want you to make sure you include a safety harness, a hard hat, rubber gloves, safety boots, a screwdriver with insulated handle, and voltage tester.

So can you annotate where those things are on this picture here? So I'd like you to pause the video now and have a go at doing the activity.

Off you go.

Brilliant, well done.

So here, we have the safety harness, which protects 'em from falling.

Rubber gloves are electrical insulators.

Screwdriver with insulated handle prevents electricity being conducted from wire to the line worker.

The hard hat provides protection from falling objects.

The voltage tester to test for electricity.

And the safety boots have hard toe caps and are made from insulating material.

Now we are onto the second part of our learning, which is protecting us from electricity in our daily lives.

Now, electrical insulators are used in many places in our daily lives to protect us from the dangers of electricity.

Now, I want you think about this question.

How are electrical insulators used here to protect us in our homes? I'll give you five seconds to think about your answer.

If you need longer, just pause the video here, and have a go, and then come back once you have your answers ready.

Off you go.

Brilliant, well done.

So we've got a plastic casing on the toaster.

We've got a pull cord light switch and a rubber coated cable.

Now all these safety measures protect us by stopping electricity from flowing into our bodies.

Alex says, our electrical appliances have cases, buttons, and handles made from electrical insulators.

And you can see here there's a plastic casing on this drill.

Izzy says, our electrical plugs are made from rubber or plastic.

Again, you've got the plastic casing on the plug just here.

And the plastic light switch.

So our plug sockets and light switches are made from plastic.

Now, lots of our transport relies on electricity.

And most trains need electricity to work.

Izzy says, how does the electricity get to the train? Do you know? I'll give you five seconds to think about your answer.

Off you go.

So some trains get their electricity from overhead cables and some get it from a third rail which runs next to the tracks, just like in this picture here.

Now these cables and rails are made from materials which are good electrical conductors, like aluminium, copper, or steel.

Now each train has an attachment which makes contact with the cable or the rail.

And here, we have a train, and in the circle is the contact point.

The electricity flows through the contact to the motors to make the wheels turn.

And finally, the electricity flows back into the rail and onto an electricity substation to complete the circuit.

Now, Alex says, why doesn't the electricity spread from the railway tracks into the ground? So insulators made from porcelain, plastic, or fibreglass prevent the electrified third rail from touching the ground.

And this stops electricity from spreading into the area surrounding the tracks.

But you should never step on train tracks as electricity can flow through our bodies and put you at risk of a serious electric shock.

So even if it seems safe, you should never ever step on train tracks.

Remember, you can't see electricity, so there could be electricity flowing, and that could give you a serious electric shock.

So you must be careful at all times to ensure that you are keeping yourself safe and protected.

Now, what type of materials are used to keep us safe from electricity in our daily lives? Is it a, metals, b, electrical insulators, c, cotton, or d, electrical conductors.

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

Off you go.

Fantastic, well done.

The answer is d, electrical insulators.

Now here is your second task for today.

Izzy has written some sentences about how insulators keep us safe.

And I want you to correct her mistakes.

So she says, number one, the cases on electrical appliances are made from conductors like metal to allow electricity to flow.

Number two, plug sockets are made from plastic or rubber to make sure that electricity can flow through it.

Number three, the circuits and wires in electrical appliances must not conduct electricity, so they are made from insulators.

Number four, conductors protect us from the dangers of electricity.

And number five, humans cannot conduct electricity.

Now I want you to have another read through her sentences and correct any of her mistakes.

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

And I'd like you to come back once you are ready.

Off you go.

Brilliant, let's see if you're correct.

So the cases on electrical appliances are made from insulators like plastic to allow electricity to flow.

Plug sockets are made from plastic or rubber to make sure that electricity cannot flow through it.

The circuits and wires in electrical appliances must be able to conduct electricity, so they are made from conductors.

And insulators protect us from the dangers of electricity.

Humans can conduct electricity.

And that's really important to remember.

So we are now onto the final part of your learning, which is protecting buildings from lightning.

Now, when electricity flows, there is sometimes more than one route it can travel.

Izzy says, if electricity could flow along rubber or metal, it would take the route made from metal.

This is because metal is an electrical conductor, but rubber is an electrical insulator.

So here, we have the metal and the rubber.

Scientists and engineers in industry use information like this to test, design, and make new and improved materials and products.

Now, who is likely to test, design, and make new and improved materials and products to keep us safe from electricity? Is it a, scientists and engineers, b, electricians and mechanics, or c, line workers and power plant workers? I'll give you five seconds to think about your answer.

Your answer is a, scientists and engineers.

Now lightning is a powerful and potentially dangerous natural form of electricity.

If it hits buildings, it can damage them or cause fires because it generates a lot of heat.

Now, scientists test materials and engineers design and improve products such as lightning rods for buildings to protect them from electricity.

Now, if lightning hits a building, it travels through the lightning rod down to a wire to the ground instead of travelling through the other building materials.

And lightning rods are made from materials which are better electrical conductors than the other building materials.

So remember, electricity will always try to go down the best electrical conductor.

So if there is more than one route, electricity is most likely to travel along the route made from the best conductor.

Now, which of the following materials would make the best lightning rod to help divert lightning away from a building and straight to the ground? Would it be a, wood, b, concrete, or c, aluminium? I'll give you five seconds to think about your answer.

Off you go.

Well done, the answer would be aluminium.

Now your final task for today is to draw a diagram and add annotations and notes to explain how lightning rods protect buildings.

So I'd like you to pause the video here and have a go at doing this activity.

Off you go.

So here, we have a diagram.

We've got building.

We've got the lightning coming down.

We've got a lightning rod made of metal, a metal wire that goes down the side of the building into the ground.

And I've labelled it.

So they've got the electricity flowing along the wire into the ground there.

So the lightning rod is made from metal, which is a better conductor than the building.

So the lightning hits that and flows down a wire safely to the ground.

Now we are on to the summary of your learning today.

People who work in some jobs risk exposure to high voltage electricity.

People who work with electricity have a variety of safety wear, or PPE, that they put on to work in certain places.

Insulators are used in many places in our daily lives to protect us from the dangers of electricity.

Scientists and engineers in industry test, design, and make new and improved materials and products.

Lightning rods can be used to protect buildings from lightning strikes.

Well done.

You've worked really hard today, and I'm so proud of your critical thinking and your hard work.

Well done.