Lesson video

- Hello, and welcome to today's lesson on insulation.

My name is Mrs. Robinson, and I will be going through the lesson with you today.

Today's lesson is about insulation, and by the end of the lesson, you will be able to describe insulation and how different insulators can be used.

So today's keywords will be an insulator is a material where electricity and heat do not easily flow through them.

Convection is the transfer of heat using particles to transport it.

Conduction is the transfer of heat from one particle to another.

And radiation is the transfer of heat using electromagnetic waves.

The lesson outline today will be: what is an insulator? Uses of insulation.

And insulation in the home.

So we're gonna start off today with what is an insulator? So an insulator is a material where electricity and heat do not easily flow through them.

Some examples of insulators would be a vacuum flask, fur, such as on a polar bear or lots of other animals.

Gloves, coats, and air would also be examples of insulators.

So insulators reduce the heat transfer by either reflecting radiation or decreasing conduction and convection.

So if we didn't have an insulator, the heat transfer wouldn't change.

Arrows are representing, they're representing heat transfer.

If we do have an insulator though, it is a little bit different.

So for conduction and convection, the insulator reduces the vibrations that particles use to transfer heat.

So the conduction and convection arrow becomes a lot smaller on the other side of the insulator.

For radiation, however, it is reflected.

So, usually, there is a shiny surface that's used to reflect radiation.

So, therefore, overall you are reducing that heat transfer.

So let's just do a couple of quick check questions.

So which is an example of an insulator? Is it air, aluminium or copper? So I hope you've gone for air for that one.

So air would be an example of an insulator.

Next question.

An insulator does not allow what to flow through easily? Is it metal, is it water, or is it heat? So, hopefully, you've gone for heat for that one.

So an insulator does not allow heat to flow through easily.

Quick true or false.

So an insulator works by stopping convection, conduction and radiation.

Is that true or false? I hope you've gone for false for that one.

So let's have a look at some reasons why that statement is false.

Is it because an insulator reduces the flow of heat transfer or because an insulator increases the flow of heat transfer? Okay, so hopefully you've gone for A, an insulator reduces the flow of heat transfer.

So it doesn't necessarily stop it completely, it just reduces the flow of heat transfer.

So well done if you've managed to get all those questions correct.

Good job.

So now you're gonna have a go at Task 1: Part A.

You're gonna fill in the gaps.

Pause the video here then resume when you are ready.

So now let's go through the answers.

So what is a material that what allow heat to travel through it easily? So you should have an insulator is a material that does not allow heat to travel through easily.

Second sentence.

So what are usually insulators.

So non-metals are usually insulators.

Other examples of insulators would be vacuum flasks, what and coats.

So I hope you've got gloves.

So well done for having a go at that.

Well done if you managed to get all those correct.

So now have a go at Part B and C for Task 1 on your worksheet.

Pause the video here and resume when you are ready.

Okay, let's go through the answers.

So Part B, what work by reducing the energy transfer by either reflecting what or decreasing what and convection.

So you should have the answers there.

So insulators work by reducing the energy transfer by either reflecting radiation or decreasing conduction and convection.

So well done if you managed to get those.

Part C, you had to draw a diagram to show an insulator reducing energy transfer.

So, hopefully, you've got something that's similar to what I have on there.

Okay, so you've got the arrow on the left-hand side.

One which is going towards the insulator, one which has been reflecting which is reflected from the insulator.

And then the other side of the insulator, you'll have a smaller arrow showing that there is less.

Well done if you've managed to get that.

So now we're gonna go through uses of insulation.

So in order to minimise heat loss, we insulate lots of things such as houses, hot drinks, and ourselves.

So here's an example with your vacuum flask.

You might wear a coat when it's cold outside.

And in your house you might put loft or wall insulation to help keep your house warm.

So a vacuum does not contain any particles.

Can convection occur? What do you think? So in your vacuum flask, convection cannot occur as there are no particles to transfer heat.

So the answer should be no, it cannot.

So now we're gonna go through how a vacuum flask works.

So vacuum flasks are a double-walled container.

So it means they've got two walls.

The gap in between the walls has the air removed from it creating a vacuum.

So vacuums where there are absolutely no air particles whatsoever.

So the vacuum does not allow heat transfer to occur by convection or conduction.

So because there are no particles, then conduction and convection cannot happen.

So you can see that in the diagram there.

So convection and conduction aren't able to go through that vacuum.

And usually also in a vacuum flask, there is a reflective surface which means that radiation is then reflected.

So, therefore, whatever drink that you have in your flask, your vacuum flask, whether it's hot or cold, then it should stay hot or cold for much, much longer.

How does a coat keep you warm? So a coat, it works by using its layers of insulation.

So air is a good insulator and the air is trapped in between the fibres which are within your coat, which reduces heat transfer by convection.

So, therefore, it keeps your warm during those cold conditions.

So you've got a diagram at the bottom there, you've got the squiggly lines representing your fibres and the circles represent the trapped air.

So if that air isn't able to move round, then your convection won't be able to happen.

Another example would be thinking about loft insulation.

So thinking about how a coat works with the insulation, how do you think loft insulation would work? So loft insulation works in a similar way to a coat.

So air is trapped between the fibres which reduces heat transfer by convection.

So, therefore, keeping your rooms below warmer for longer.

So again, you've got that same diagram there as before.

The exact same principle as we had.

So let's do a quick check question.

So a true or false.

Vacuum flasks work by creating a vacuum to stop heat transfer by convection.

Is that true or false? Okay, so I hope you got the answer to this one.

That would be true.

Why is that though? Is it because convection uses waves to transfer heat, or because convection needs particles to transfer heat? So we're going for A or B there.

If you need to have a discussion, pause the video here and then resume when you're ready.

Okay, so let's go through that answer.

So we should have gone for convection needs particles to transfer heat.

So well done if you've got that.

Now you're gonna do Task 2: Part A.

So you're gonna circle the insulator.

So pause the video here and continue when you are ready.

Okay, so let's go through those answers.

So I'm gonna pop the answers on the screen for you.

So we should have circled flask, coat, wall insulation, air, gloves, rubber, blanket, and a window.

So the ones that we should not have circled would've been the copper pipe, a metal spoon, and a coin.

So well done if you've managed to get those.

Now have a go at Task 2: Part B and C.

Pause the video here and then resume when you are ready.

Okay, so let's go through the answers.

So Part B, why should you use a wooden spoon instead of a metal spoon with stirring a hot pot of food? So I'm gonna pop a model answer on there for you.

So wood is an insulator and therefore would not allow the heat to transfer to your hand.

If you use a metal spoon, then that heat would transfer along the metal spoon to your hands.

So, hopefully, you've managed to get that.

Part C, why would I be better to use a ceramic mug over a metal mug to keep my hot chocolate warm? So again, I'm gonna put a model answer up for you and I hope you've got this.

So ceramic is an insulator and metal is a conductor.

So, therefore, ceramic would not allow the heat to transfer easily.

So then that would be keeping your hot chocolate warmer for longer.

So well done if you managed to get those.

So now have a go at Task 2: Part D.

Pause the video here and continue when ready.

Okay, so hopefully you've had a good go at that.

Let's go through the answer.

So why would a snowman with a coat take longer to melt than a snowman without a coat? So here I'll pop up a model answer.

So you should have something like the coat acts as an insulator keeping the snowman with the coat cooler for longer.

So it slows down that heat transfer.

So well done if you've managed to get that, good job.

So now we're gonna go on to insulation in the home.

So look at this thermogram of a house.

The roof, the windows and walls are the hottest showing that most heat is lost from the house through those parts.

So you can see how the walls have got that red colour.

That's quite warm, that's from the outside that we're getting that.

The windows are more yellow, so a little bit cooler than the walls, but still quite warm.

And then the roof is quite yellow as well.

And you might notice some of the surroundings you have, you have your blue, which means it's cold, okay, which is what we want.

We don't want that heat being lost from the house.

So we're gonna look at ways at how we can help reduce that.

So first we're gonna look at ways that heat is lost at your home.

So it could be lost by conduction and convection through the roof.

It could be lost by radiation through the windows.

There could be heat loss by conduction through the walls.

Heat loss by conduction through the doors.

And heat loss by conduction through the floors as well.

So there's lots of different things that we need to look at and see if there's anything that we can do to reduce that heat loss.

There are multiple ways to reduce heat loss in the home.

Things such as laying loft insulation.

So it'll be some fibreglass material that we usually use to place in a loft to help with that insulation.

We could also instal cavity wall insulation.

So between your inner walls and your outer walls, you have a gap, and you can instal some insulation there as well to help with reducing heat loss in the home.

We could also use double-glazed windows.

So double-glazed windows have two panes of glass that are side by side, and the air between that glass is either reduced greatly or would have used other alternative gases.

So ones that would reduce heat loss.

And we could also fit carpets, curtains, and draught excluders in your home.

All of these are ways to reduce heat loss in the home.

Let's look at this house.

Do you notice something quite different about the roof on this that I've circled in this picture? Pause the video here, have a little discussion about it, then resume when you are ready.

Okay, so I hope that you've noticed the difference, and some of you might know already what it is.

So this method is called thatching.

So that roof has got thatching on it.

It's a method used with straw, heather and palm branches, and these are tightly packed together, trapping air.

So this works as insulation.

So this helps to keep your house warmer, okay, 'cause it's reducing that heat transfer through the roof.

So let's do some quick check questions.

So which is an example of insulation in the home? Is it using single-glazed windows, laying loft insulation, or laying laminate flooring? Pause the video here and resume when you're ready.

Okay, so I hope you went for laying loft insulation.

So that's an example of insulation in the home.

Now you're gonna do Task 3: Part A.

So you're gonna design a house with insulation, label the different parts of the house with the insulation you have chosen to use, and explain how the insulation helps to keep the house warm.

Pause the video here and continue when you are ready.

So well done for having a go at that task.

I'm gonna go through an example that I have here.

So I'm using the same diagram I had for the house before and then I'm gonna show you what I have labelled it as.

So, for example, I've put double-glazed windows reduce heat loss by radiation.

So using curtains also help to reduce heat loss.

We could also write that using draught excluders reduce heat loss by conduction through the doors.

Whilst installing carpets help to reduce heat loss by conduction through the floors.

Using cavity wall insulation reduces heat loss by conduction through the walls.

And also that using loft insulation reduces heat loss by conduction and convection through the roof.

So well done if you've got something like that.

Good job on that, there's a lot of information in there to include.

So now have a go Task 3: Part B.

You have a table of information there to look at as well.

You've got approximate cost of your insulation type, how much you would save each year using that insulation type, so your yearly saving, and then also the approximate payback time.

So how long it would take for you to get your money back from putting the upfront cost of paying for that installation time.

So pause the video here and then resume when you are ready.

Okay, so let's go through the answers.

So you had to look at the table below, and if you had a thousand pounds to spend on insulation, which options would you choose and why? And I wanted you to use values in your explanation.

So a model answer would be I would choose to instal loft insulation and cavity wall insulation.

So if we look at the cost for those, it was 300 pounds for loft insulation, 475 pounds for cavity wall insulation.

These are the cheapest options to instal at a total cost of 775 pounds, with the greatest combined yearly saving of 330 pounds.

So if you had an answer similar to that, that'll be absolutely brilliant.

So well done for getting those.

So let's do a quick summary over that lesson on insulation.

So an insulator is a material where electricity and heat do not easily flow through them.

Insulators work by reducing the energy transfer by either reflecting radiation or decreasing conduction and convection.

Some uses of insulators are coats, vacuum flasks, and reducing heat loss in the home, such as your loft insulation, double-glazed windows.

Thank you for taking part in the lesson from Oak National today.

I hope you enjoyed it and that you've learned a lot.

And now have a go at the exit quiz, goodbye.