Lesson video

Hello, my name is Mr. Wilshire, and in this lesson we'll be looking at the uses of everyday materials.

The outcome for this lesson is I can use test results to explain some uses of everyday materials.

The keywords for this lesson are physical properties, material, results, and suitable.

Don't worry if you're not too sure what some of these words mean.

The definitions are on the screen for you now, so you can pause a video here and have a recap if you need to.

The outcome for this lesson is knowing the properties of materials.

Now, Sam and Alex have been investigating the physical properties of materials.

Here's Sam and Alex there.

Can you explain to a partner what physical properties are? Take a moment to do that now.

Were you able to remember what physical properties are? Let's see if we can recap.

The children group the materials, depending on their different physical properties.

Here is an example of their table.

One side says conduct electricity and the other does not conduct electricity.

And you can see the different materials that they tested.

The paperclip and the aluminium foil were able to conduct and the kling film, the cup, and the toy were not able to conduct electricity.

So physical properties tell us exactly what a material is like.

In that way, we are then able to choose the best type of material for the job.

You wouldn't want to go somewhere without a waterproof jacket, would you? So it's always best to make sure that you choose a waterproof material to take with you.

I wonder which properties that you've tested.

Are there any materials that you've found to also conduct electricity? Or maybe you chose some different answers like smooth and rough for example.

Sam and Alex grew the results of all properties into one table.

Let's take a look.

Here you can see their table.

They've got the materials listed down the left hand side and the different properties there as well.

Rigid, transparent, conducts electricity, and magnetic.

But why is it useful to know the properties of materials? Do you know? What's the point? Why have you written all this data down? Discuss.

So why is it so useful? Why would it be useful to know if something is able to conduct electricity? Why would it be useful to know if something is magnetic or transparent, or not transparent? Is it a good idea to know if something is rigid or not rigid? Let's stop and think.

The features of a material that can be observed or measured are called its blank.

The correct answer here is properties.

So why is it so important to find out why materials have got different properties? Well, the properties of materials can make them suitable for some uses and unsuitable for other uses.

For example here you can see some water containers that are made from different materials.

The results of a scientific investigation allows us to explain why materials are suited to particular uses.

When engineers design objects, they must think about what they need those objects to be able to do.

Of course, it's no good building something that needs to be waterproof out of cardboard is it? Engineers can then choose materials with suitable properties that allow the object to function in the best way possible.

For example, you can see a window here.

I wonder what properties materials suitable for a window would need.

Have a little think, what physical properties are going to be needed for the window? Do you know which properties you're going to need to make a window? Well, it needs to be see through, doesn't it? But it also needs to be hard.

You don't want to be able to put your hand through it, do you? Sam says a window needs to be transparent and it needs to be hard.

Oh, that's exactly what I said, fantastic.

Yes, you need to be able to see through it.

Although actually if you are going to the bathroom, usually you can't see through the windows there.

It's usually frosted, isn't it? So sometimes it would depend on what it is being used for.

What properties does the materials suitable for a wire in an electrical circuit need? Think about that question.

What properties does it need? Pause the video here and discuss.

Well, a wire, as Alex says here, needs to be flexible and it needs to be an electrical conductor.

Oh yeah.

You can't just have a wire that's just a straight rod.

That wouldn't be very useful, would it? You wouldn't be able to get it round corners and things then it also needs to be an electrical conductor to be able to transmit the electricity along it there.

But it does need to be wrapped in an insulator though, doesn't it? Which is a very good reason why it's important to know whether something is a conductor or an insulator, just one of their physical properties.

What properties does the material suitable for a jumper need? Have a think here.

Well, the materials suitable for a jumper would need to be soft and flexible, just as Sam has said there.

Yeah, I wouldn't want to wear a cardboard jumper.

That wouldn't be very soft.

It wouldn't be very flexible.

Which of these is the most likely way that scientists find out whether particular materials are suitable for particular uses? Read the statements there and decide.

The correct answer here is carrying out investigation.

Scientists are able to find out the particular materials suitable for particular uses by investigating.

This brings us on to task A.

Use the results from your own earlier investigations to name a material which does and does not have the following physical properties: rigidity, transparency, electrical conductivity, attraction to magnets.

Those are your four areas to think about.

Sam and Alex here say, we might like to use our results on the next slide.

Ah, okay, so let's have a little look at these results.

Here are their results.

If you've got your own results, you can use those if you'd like to.

Here you can see that Alex and Sam have tested the different materials.

They've tested two different types of metal.

They've tested plastic and glass and wood as well.

They've then thought about the physical properties there, whether it's rigid, transparent, conducts electricity or magnetic.

Use these if you need to.

Best of luck with your task.

How did you get on? Now you needed to use your results to name a material which has that property and one which does not have that property.

So you may have chosen the material similar to here.

Here, for example, there was rigid and transparent conducts electricity and attracted to magnets.

Now, one item that was rigid is wood.

The other item that didn't have that property was plastic.

Transparency, well, the glass definitely has that property, but metal does not.

Conducted electricity, the metal does and the plastic does not.

And being attracted to magnets, well again, the metal did, but the wood did not.

Were your results similar to this or did you have something slightly different with your results because you chose some different materials? Well done for completing that task.

The final part of this lesson is called choosing materials based on their properties.

Now, Sam has observed something a little bit confusing.

Here's Sam, and she says, "Oh, this plastic is flexible and transparent.

Here you can see a plastic bag as an example.

Oh, but this plastic is rigid and opaque.

Oh, I see what she means there.

Yes, both of them are made out of plastic, but both of them are different.

They have different properties.

Now, some materials come in different types which have got different properties.

You can use them for different things or if you can think of any examples of this though, pause video here and have a think.

Restart when you've done that.

I wonder if you could think of any examples other than this.

Well, the plastic bag and the plastic bin are two such examples.

Maybe you had a thought of, well, paper is made out of wood, isn't it? But actually you can use wood to build things and it can be very rigid.

Hmm, I wonder what other examples you thought of.

Well, for example, there are lots of different types of metals and they don't all have the same type of properties.

So I wonder if you can remember which metals are attracted to magnets.

Have a think.

Now iron is attracted to magnets, but aluminium is not.

So here's iron and aluminium.

You use both of those for different things.

Gold and tungsten are both metals, but gold is soft and tungsten is very, very hard.

So all of these things are similar.

They're all types of metal, but they all have different properties.

I wonder why.

Have you thought of any other materials like this? Have a think.

Great discussing.

Let's move on and find out more.

For example again, there are lots of different types of wood.

Each one has got its own different property, which makes it suitable for different uses.

Bamboo, for example, is very flexible and lightweight.

It's also biodegradable.

Oak is rigid and strong and also biodegradable.

So would you use al bamboo to make disposable cutlery.

Well, bamboo is flexible and it's lightweight.

It's also biodegradable a lot better than using plastic cutlery.

Oak, however, isn't very flexible, is it? So I don't know if that would be very good for cutlery, but I wonder if you would use oak or bamboo to make a table and why? Yes, you would definitely use oak to make a table.

Oak is rigid and strong and biodegradable.

I think it would be very hard to make some oak cutlery that's this thin and easy to transport around.

If you did need to use oak to make cutlery, I think it would be a lot thicker than this.

Bamboo wouldn't make a very good table because it's very, very bendy and flexible.

Not the best thing to balance your chips on if you're trying to eat them.

So scientists and engineers choose materials for different uses based on their physical properties.

Plastic is often used to make packaging for food.

Here you can see some plastic packaging.

So what properties of plastic make it really suitable for this? Pause the video now and discuss.

Well done.

Now, plastic is lightweight, it's waterproof, and it can be made in different shapes and different forms. If you're able to heat it up a lot, then you are able to make it very, very thin, and that can make the flexible bags that you can see there.

The only problem with this though, is that plastic isn't very good for the environment.

So why do you think brick has suitable properties for construction? Have a look at that brick there on the wall.

Why are those two good things to use for construction? Well, brick is very hard.

It's very rigid, it's very strong, and it can be formed into different sizes and shapes.

If you've also got the right tools, you're able to cut it down into those different sizes and shapes to fill in smaller gaps.

You don't just use brick just to build a building though, do you? You need lots of other materials as well to give it some support.

The bricks provide that really hard outer layer.

Understanding the properties of materials also helps engineers choose which materials are unsuitable for particular tasks.

You wouldn't use wax to make a saucepan, for example, Uh, but why not? Discuss.

Of course, wax melts at really low temperatures.

Even if you were to leave a wax candle out in the sun, it would start to go a bit funny.

So a saucepan made outta wax would melt when it was heated on a cooker.

In fact, it might start melting even when you're holding it in your hands.

Which materials would not have suitable properties for making a pair of trousers? Have a think.

I think glass isn't suitable to make a pair of trousers.

Yeah, Sam, I think you're right there.

It's not rigid, it's transparent.

Ooh, you don't wanna be able to see through trousers and also it could shatter and cause quite a lot of harm to people.

So yeah, glass, definitely not a good idea to use for trousers.

Do you have any other ideas though? Are there any other materials you can think of that are really not very good to make different objects? Have some fun thinking of these.

Restart the video when you've done that.

Maybe you thought of a paper boat or perhaps you might want to go to space in a cardboard rocket.

Who knows? Some of those materials definitely are not useful for those types of jobs, are they? Let's stop and think.

Scientists and engineers choose blank for different uses based on their physical properties.

The answer here is materials.

Scientists and engineers choose materials for different uses based on their physical properties.

True or false? If you know the properties of one type of metal, then you will know the properties of all metals.

What do you think? The answer here is false.

Can you justify your answer? Read the two statements below and choose which one best fits.

The answer that best fits here is A.

Some materials like metal come in different types which have different properties.

This brings us on to the final task, task B.

Choose which materials would be most suitable and least suitable for these objects and explain why.

Record your results in a table like this.

The objects are listed down the side there.

There's a window, a device to keep the fridge door closed, the wires in an electrical circuit, and a tabletop.

Choose the materials that are suitable for this and the materials that are not suitable for this.

You could use your own test results to support your explanations here.

And if you've done those four really quickly, you can start thinking of some of your own devices and gadgets that would have a suitable material and a not suitable material.

Best of luck with your task.

Restart the video when you've done that.

So let's see then.

Your answers may be similar to this.

Let's read through.

A window will need glass to be rigid and transparent.

A device to keep the fridge door closed will need steel on the door and a magnet on the other side.

Oh yes, of course it's magnetic.

It's gonna keep it shut, but still allow you to open it up depending on the strength of the magnet.

Things not suitable for this are wood.

You know, wooden windows aren't very good and a device to keep the fridge door closed are aluminium.

It's not magnetic, so it's not going to be attracted, is it? The last two here, the wires in the electrical circuit need to be made up of any metal because they're electrical conductors.

And of course the tabletop there needs to be made out of wood needs to be nice and rigid.

Not suitable, however, is any type of plastic for wires, it won't transmit electricity.

And the tabletop, again, plastic used in cling film that's very soft and flexible.

I don't think a cling film table is going to work very well.

Well done for completing that task.

Let's summarise our lesson.

The physical properties of a material are the features that can be observed and measured.

The results of investigations enable us to explain why materials are suitable for particular uses.

Some materials come in different types, which have different properties.

Scientists and engineers choose materials for different uses based on their physical properties.

Now you know lots about the uses of everyday materials.

You're going to be able to go on to think of how materials could be used to best help you.

The next time you head out in the rainstorm are you gonna grab something waterproof or maybe a cardboard box? I'll leave that decision up to you.

I'll be Mr. Wilshire.

Thank you very much for listening.