Lesson video

Hi, I'm Mr. Brown, and welcome to this unit about properties of materials and manufacturing.

And today we're gonna be looking at material selection.

That's gonna be thinking about the properties of materials.

It's gonna be thinking about how we choose materials and why we choose them.

So without further ado, we'll get onto the learning outcome and the learning cycles for today.

And here's today's learning outcome.

Today's learning outcome is about selecting the most appropriate materials using properties and chooser charts.

And if you're wondering what chooser charts are, don't worry.

We're gonna be covering that later in the lesson.

And the keywords for today, well, there's four keywords which are all alliterative and they're product, purpose, place, and person.

And there is a reason why there's alliteration there, and you'll find that out, certainly when we get onto looking at the learning cycle.

But let's go through them one by one.

Product, the object that's gonna be designed and created.

Purpose, the intended function of the product, so what is it actually going to do? Place, where is the product gonna be used? And person, the user of the product, who is actually going to use it? And here is the lesson outline.

So we've got two learning cycles today.

First learning cycle is purpose, place, and person, told you there'll be the alliteration there.

And we're talking about that as the three P's.

And then the second learning cycle will be about material properties.

And this will include learning about chooser charts.

Our first learning cycle is purpose, place, and person, the three P's.

And we're gonna be thinking about how designers use these when they're designing products.

So when selecting materials for products, designers consider different factors.

So the different factors, we've already covered them a few times, are purpose, which is the intended function of the product, place, which is where the product is going to be used, and person, so the user of the product, who's actually going to use it.

So we're thinking about why we're actually making this product, where we're gonna make this product, and who we're making this product for.

Check for understanding.

So when selecting materials for a product, designers consider different factors such as purpose, person, product, place.

Which of these are actually correct? And there is more than one.

And think back to the title of the learning cycle, just for a little bit of a hint.

Yes, well done.

It's purpose, place, and person.

The product is not one of the things that they consider as a factor, but it's gonna be one of the outcomes of these considerations.

Okay, so let's look at products now.

So this is a chair.

You probably recognise these sorts of chairs.

And this is a chair with a polymer seat and tubular steel legs.

So what is its purpose? Its purpose is to be sat on.

Where will it be? So what place? in a classroom or a school hall.

And who's gonna be sat on it? Well, it's likely to be school children or school staff.

There might be visitors, there might be parents, there might be other people that come into the school to use it, like governors for example.

But predominantly school children and school staff is who it's really designed for.

Now, this is a different type of chair.

This is an office chair, and it's got the same purpose, 'cause you need people to sit on it, but the place and person are different.

Now, this may affect the design decisions.

For example, materials that are used or the overall design.

So the purpose is to sit on.

The place is now an office.

And this is more likely for office workers who are adults to be using.

Check for understanding.

So what I'd like you to do is to match the definition to the keyword.

We've gone through these a couple of times now, so hopefully this will be okay.

So we've got purpose, place, person on the left-hand side, and then on the right-hand side, the three definitions, which is where the product will be used, the user of the product, and the intended function of the product.

So take a minute, just match the definition to the keyword.

Right, hope you worked it out.

So purpose is the intended function, place, where the product's going to be used, and person, who is going to be using it.

Well done.

We're gonna look at the two chairs that we've looked at earlier, the office chair and the classroom chair.

And just think about the materials that have been used and why they've been chosen for those different purposes.

So they've both got the purpose of to be sat on, but actually there are other purposes as well, which are slightly different.

And other requirements that are needed.

So a school chair needs to be easy to clean.

It could be used where someone's painting.

And so polypropylene is really easy to wipe clean.

An office worker, the materials chosen there and the design of the office chair.

The office worker may be sat in one seat for a number of hours, and so it needs to be comfortable.

And so that's why the seat is soft fabric and cushioned.

And that is why there is a difference between the two when it comes to material choices.

Onto Task A, part of our learning cycle one, about purpose, place, and person, the three P's.

What I'd like you to do now is to have a look at these three different types of seating and identify the purpose, the place, and the person for each of these products.

So we have a sofa, folding deck chair, and a stool.

So what is the purpose of them? Where is the place? And who is the person for each of these products? That's the first step.

So once you've done that, then you move on.

And what we'd like you to do would be to explain how the three P's have affected the design decisions, but focus in particular on material choices.

Can be other things as well, but do think about the materials that are used for each of those and why they've been chosen.

Okay, so there's two different aspects of this task.

Off you go.

Welcome back.

Hope you were able to access that task, I'm sure you were, and have some interesting discussions as to the purpose, place, and person for each of the products.

Let's go through them one at a time.

So the first one is the sofa.

So what purpose has it got? Well, the main purpose is to sit back, relax, maybe watch some TV, maybe play some games.

The place, usually found in a lounge or a living room at home.

And the person, usually designed for family.

Obviously there can be changes for this, but this is for the majority.

Folding deck chair, so a folding deck chair, what is its purpose? Sit back, to relax, to sunbathe.

And where is it found? It could be at the park, could be a beach, could even be on the pier.

And who's the person? It's usually designed for an adult.

When you look at the size of them, they're usually designed for adults.

I know children have fun trying to get into them, and you can get smaller ones, but usually, folding deck chairs are designed for an adult.

And lastly, a stool.

So what is its purpose? Again, is to sit on.

Where is its place? Can be in a science laboratory, you can see it in other different places as well.

And who's the person? Usually it'll be for a school child or a scientist.

There can be other uses for these types of stools, but this is, for this particular one, that's what it's designed for.

You may have come up with some other ideas, and that's not a problem at all.

When we're thinking about explaining how three P's have affected the design or the choice of the materials, this is an example.

So for the sofa, it's large enough to fit several members of family.

It's also soft and cushioned, so it'll be very comfy.

That affects the material choice that we're gonna have/ The deck chair, that folds, so it makes it easy to move and store when it's not in use.

It needs to be a certain type of material that's gonna be quite robust, easily foldable, and it can actually be stored easily as well.

So there are different considerations when we're choosing materials.

Lastly, the stool has got wipe clean materials.

So it's important, because we need to have hygienic science labs if that's where it's decided to go.

Well done.

That's learning cycle one over.

Learning cycle two is thinking about material properties.

So when designing a product, it's important to choose the most appropriate material, and that's really important for designers when they're thinking about which product they're gonna do and what they're going to be making out of.

One way to determine this is to consider the product requirements and the material properties required.

So just to go into a bit more detail about what that actually means, it means if the product is gonna be, for example, used outside, will it need to be waterproof? Or is it gonna be under cover? So that's gonna have a real impact upon the material that you choose.

If the product is designed to hold something hot and needs to insulate heat, then that needs to be considered as well.

Because what you need to think about is if a material is a conductor of heat, then of course the heat is gonna come through the material and then that could actually burn someone's hand.

So all of these different considerations, these are just two examples of considerations that designers have to make.

Check for understanding here.

So there are three material properties and three definitions.

What I would like you to do is to match them together.

So the three material properties are compressive strength, electrical conductivity, and heat insulator.

And the three definitions are how well a material allows electricity to pass through it, a material that does not allow heat to pass through easily, and the ability of a material to resist crushing forces.

Start with the ones that you know and that'll help you with the ones that maybe you don't.

Okay, I'm gonna leave you to it.

Off you go.

Welcome back.

Let's go through the answers.

Compressive strength.

Compressive strength is the ability of a material to resist crushing forces.

Electrical conductivity is how well a material allows electricity to pass through it.

And a heat insulator is a material that does not allow heat to pass through easily.

Well done.

Right, these mugs have different product requirements, and so the materials that have been chosen have got different properties.

So I'm gonna go through each one as different examples.

So on the left you have a stainless steel mug with a polymer lid.

So we're gonna think about why these materials have been chosen for this product requirement.

In the middle, we've got a ceramic mug, and on the right-hand side, we have a paper cup with a polymer lid.

So we can put these different types of mugs and cups into a chart or a table.

That will show you the different properties that they have and we can start sorting them.

You can see there the three columns on the right-hand side, we have got the stainless steel mug, the ceramic mug, and the paper cup.

And then on the left-hand side are different properties.

So it's non-porous, so it doesn't absorb liquid, suitable for washing, so it can be safely reused.

Compressive strength, so it resists crushing forces, so it doesn't deform when it's dropped.

So it doesn't change.

Non-corrosive, so it doesn't affect the drink, and can be recycled after use.

If we have a little look at these, some of these cups and mugs have got those properties and some of them do not.

So for the first one, non-porous, the paper cup does absorb liquids and isn't suitable for washing.

So it isn't really something that you tend to reuse very well.

Compressive strength.

The stainless steel mug, if it drops, it doesn't usually deform when dropped, and can be reused again.

Sometimes, of course, it may do.

But ceramic mugs and paper cuts, when they're dropped, they do tend to deform or break and can't be used again.

Being non-corrosive does not affect the drink.

That's all three, because if it wasn't, if it was corrosive, then it would make a really bad taste for the drink that's inside.

And that's definitely something we don't want in any of these cups.

And which can be recycled after use? Well, stainless steel mugs can be, and paper cups can be, but not ceramic mugs.

So when we look at all of this, we consider actually what is the best material or maybe the most appropriate material for a mug is stainless steel.

But most mugs are not stainless steel, because this is quite expensive and it does have a metallic feel when it's drinking, and it can be more difficult to decorate.

Ceramic mugs are more popular and we do tend to have those a lot more, 'cause people prefer the smooth, non-metallic feeling when they're drinking it.

But material choices are always about considering the products alongside the purpose, the place, and the the person.

Check for understanding.

What are the disadvantages of stainless steel for a mug? Is it that it's shiny, that it tastes metallic, or it's difficult to decorate? You decide.

That's right.

It can taste metallic and it can be difficult to decorate, but being shiny is not necessarily a disadvantage.

But let's first of all have a look at the different materials.

We've got polypropylene, stainless steel, pine, and cotton.

Now, these different materials have different properties and they are suited to different products.

And what we can do is we can use chooser charts to identify which material is best for which product, and by considering the properties that that material actually has.

And when we put them into a chooser chart, this is a very simple chooser chart, just showing these four different materials, looking at their properties and potential products that they could be made from.

So polypropylene is easily coloured, flexible, hard wearing, easily moulded, and non-porous.

And that tends to be used for chairs, folders, drinking cups.

Stainless steel, that's malleable, ductile, high strength, corrosion resistant, and non-porous.

And that can be used for cutlery, kitchen sinks, or as we saw in the previous slides, can be used for a mug as well.

Pine is tough, it's lightweight, soft, it's porous.

And we usually use that for indoor joinery, for example, within a door frame.

And lastly, the last material we're gonna look at is cotton.

And that's cool, strong, inexpensive, renewable, and porous.

And we tend to use that for clothing.

Okay, check for understanding.

What are chooser charts used to identify? Is it most appropriate materials, most cost-effective materials, or most aesthetically pleasing materials? Have a little look and you decide.

Well done.

That's right.

The most appropriate materials is what chooser chance help us to actually justify and identify, so that when we're designing, we can choose which materials are the best ones.

So we're gonna go through individually and think about that chooser chart of why stainless steel was used for the body of a travel mug.

So it's malleable, it's ductile, so that makes it fairly easy to actually manufacture a round shape.

It's got high strength, so if it's dropped, it won't be deformed.

And it's corrosion resistant and non-porous.

So it's suitable for drinks, which won't be absorbed or tainted.

Polypropylene for a drinking cup.

Well, we've actually got the lid, if you look very carefully, the travel mug has actually got a lid, and polypropylene is being used as the lid of the travel mug.

And that's 'cause it's easily coloured.

So we can have lots of exciting, different colours.

It's flexible, so it can be pressed into the stainless steel mug, so it creates a good fit.

And manufacturing the lid will be quite easy.

Polypropylene is easily moulded.

It's also non-porous, which makes it suitable for drinks, as it won't be absorbed.

Onto task B.

So look at the chooser chart below.

And what I want you to do is to explain why polypropylene and steel were used to create a school chair.

So why were they designed? Why were those materials chosen? And if we have a look at the different materials in that chooser chart, we have polypropylene, steel, and pine, and there's a list of the properties, and there's a list of the products that they would maybe make.

What I want you to do now is to look at the chooser chart, look at all the information within the chooser chart and at the chair, and then explain why polypropylene and steel were chosen for the school chair.

I'll see you in a few minutes.

Welcome back.

Sure you did a great job.

Here's an example of some feedback that we can provide, thinking about the chooser chart on why polypropylene and steel were chosen for the school chair.

So polypropylene is suitable for the seat, 'cause that's easily moulded into a curved shape.

You can get lots of different colours, which means different classrooms or schools can choose different colours.

It's hard wearing, it's flexible, so it means a lot of children can sit on it over and over again without it breaking.

And that's really good so that we can have it long-lasting.

Steel is used for the legs of the school chair because it's got high strength, but it's also malleable, so it can be made into the frame really easily.

And onto today's summary of the lesson, Material selection.

So today we've looked at the person, place, and purpose, the three P's of a product, and how that can affect material choice.

We've talked about product requirements and material properties and how they are considered when selecting materials.

We've also talked about how sometimes there are several different materials which are suitable.

And lastly, how it's important to explain and justify the choice of materials.

And that's it.

Thank you very much for joining me today.

I hope you've had a good time and that you've learned something, and I look forward to working with you next time.

Okay, great.

Thank you very much.

Bye.