Lesson video

Hello there, my name's Mrs. Taylor and I'm really pleased you can join me for our lesson today.

Our lesson today is "Material considerations and selection." The outcome, I can explain how a range of factors affect material selection in industry.

There are four keywords.

Physical properties, which is the characteristics of a material, such as appearance and features.

Working properties, the way in which a material responds to an external force or certain environment, also referred to as mechanical properties.

Performance, how well a product or material works.

And sustainability, a product or material that has minimal environmental impact through its reuse or replenishment.

There are two learning cycles in this lesson, "How material properties influence choice" and "Other factors influencing material choice." Let's begin.

Industries select materials based on several key factors, ensuring the final product is functional, cost-effective and sustainable.

The three main factors in material selection are performance, how well the material meets the functional needs of the product; cost, the price of the material and how it affects manufacturing; and sustainability, the environmental impact of sourcing and using the material.

Performance refers to how well a material does its job and is linked to its properties.

There are two characteristics of material properties.

Physical properties include appearance and characteristics, and working properties include behaviour and mechanical.

Here we have a check.

Fill in the blanks using the words on the right.

Pause the video.

Fantastic, let's check.

Physical properties include appearance and characteristics, and working properties include behaviour and mechanical, well done.

Physical properties refer to the characteristics of a material, such as appearance and its features.

Examples include conductivity, which could be thermal or electrical, density, colour, or weight, texture, absorbency, magnetic, or acoustic.

Andeep says, "These words describe the material before its use." Working properties refer to the way a material behaves when subjected to an external force, for example, bending, or an environment, for example, moisture.

Examples include strength, which might be tensile or compressive, flexible, elastic, or durable, tough or hard, moldable and malleable.

Laura says, "Malleable refers to metals only.

For other materials, for example, polymers, we use the word moldable.

These words can also be called mechanical properties and describe a material's behaviour during its use." Here we have a check.

Which material property is most important for making electrical wires? Is it A, durability; B, electrical conductivity; C, flexibility; or D, weight? Pause the video and have a go.

Fantastic, let's check.

That's right, it's B, electrical conductivity, well done.

A material's physical or working property will determine its performance.

Key considerations include strength.

Can it withstand forces without braking? Flexibility, can it bend without snapping? Durability, how long will it last before wearing out? Or weight, is it light or heavy? Aircraft parts are made from aluminium instead of steel because they need to be lightweight yet strong.

Bridges are made of steel and concrete because they must handle high weight loads and last for decades.

Different industries rely on materials with specific physical and working properties.

Aerospace needs lightweight but strong materials.

For example, carbon fibre.

Construction needs durable weather-resistant materials.

For example, concrete.

And fashion needs flexible and soft materials.

For example, cotton.

Here we have a check.

Match the material to its most important property.

The materials are glass, rubber, steel, and cotton.

And the properties include flexibility, strength, softness, and transparency.

Pause the video.

Wonderful, let's check.

Glass would need to be transparent.

Rubber, flexibility.

Steel, strength.

And cotton, softness, well done.

Here we have Task A.

You'll be given a collection of five material samples from a range of different categories.

Part one, for each material, give one physical property.

And part two, identify the name of the material sample and suggest one working property and one application.

Application means use, where it might be used.

Pause the video.

Great, let's have a look at some of the answers you may have come up with.

Part one, for each material, give one physical property.

Rough, shiny, light in colour, fuzzy, and lightweight could be your answers.

And part two, identify the name of the material sample and suggest one working property and one application.

So the first image we have here is chipboard.

It has good compressive strength and is often used for kitchen worktops.

Next we have steel, which is hard and is used for cutlery.

Pine is durable and often used for flat-pack furniture.

Felt is flexible and maybe used for a hat.

And polypropylene is tough and is often used to make the seat of a chair, well done.

We now move on to our second learning cycle, "Other factors influencing material choice." As well as performance, industries consider other factors when selecting materials for products, including cost, how expensive the material is to buy, process and manufacture.

Sustainability, the environmental impact of the material, including how it is sourced, produced, and disposed of.

Here we have a check.

Which of these is not a key factor in material selection? Is it A, cost; B, colour; C, performance; or D, sustainability? Pause the video.

Great, let's have a look.

That's right, it's colour, well done.

Industries must consider the cost of materials because it affects the overall price of the product.

Factors that influence cost include raw material cost.

Some materials, like gold or titanium, are expensive.

Processing cost.

How easy is it to cut, shape, or mould? Gold is an excellent electrical conductor but is very expensive.

Polymer garden chairs are cheaper than timber or metal as they are easier to mould.

Car manufacturers use different materials depending on the type of vehicle and its purpose.

This has an effect on its cost.

Steel is used in budget-friendly cars due to its strength and low cost.

Aluminium is used in high-performance or luxury cars because it's lightweight and corrosion-resistant.

Carbon fibre is founding racing cars for maximum performance despite its high cost.

Sustainability means choosing materials that reduce harm to the environment.

Factors include renewability.

Can the materials be replaced? For example, wood versus plastic.

Recyclability.

Can it be reused instead of going to waste? And carbon footprint.

How much energy is used to produce it? Recycled aluminium requires less energy to produce than new aluminium.

Bamboo is replacing plastic because it grows quickly and is biodegradable.

Industries must balance performance, cost, and sustainability when choosing materials.

There is no perfect material.

Each choice involves trade-offs, which means accepting a minor disadvantage for something good or an advantage.

For example, electric cars use lithium batteries, which are high performance but very expensive.

Fast fashion uses synthetic fabrics which are low cost but they are not sustainable.

Here we have a check.

Match the material to the reason it is used.

And the material choices are aluminium, low-density polyethylene, or LDPE, steel, and glass.

And the reasons include high strength and cost-effective, lightweight and moisture-resistant, lightweight and rust-resistant or durable and transparent.

Pause the video.

Wonderful, let's check.

The aluminium is lightweight and rust-resistant.

The LDPE is lightweight and moisture-resistant.

The steel has high strength and is cost effective.

And the glass is durable and transparent, well done.

Here we have Task B.

A company is designing a new reusable lunchbox and must choose between the following materials, polypropylene or stainless steel.

Discuss the advantages and disadvantages of both material choices.

Explain which material is the best choice based on its performance, which includes its working and physical properties, the cost and the sustainability.

Pause the video.

Fantastic, let's have a look at some of the answers you may have come up with.

Polypropylene is a lightweight polymer that is resistant to impact and doesn't rust, making it a good choice for a lunchbox.

It's cheaper to mould into different shapes, but it is not as hard as steel and can scratch over time.

Stainless steel is stronger and resistant to heat, it is fully recyclable, but it is heavier than polypropylene.

Stainless steel is more expensive to produce, which may make the lunchbox less affordable.

Example option one.

Polypropylene is the better choice due to it being cheaper and lightweight.

While stainless steel is more sustainable and durable, its higher price and weight may be a disadvantage.

Example option two.

Stainless steel is the better choice due to its durability and sustainability.

While polypropylene is cheaper and lighter, stainless steel's strength and recyclability make it a more responsible choice for a reusable lunchbox.

Well done.

Here we have a summary of our learning today.

Materials have different physical and working properties which affect their suitability for different products.

Industries choose materials based on performance, cost, and sustainability, balancing these factors to meet product needs.

Performance factors like strength, flexibility and durability determine how well a material functions in its intended use.

Sustainability is increasingly important with industries considering recyclability, renewability, and environmental impact when selecting materials.

You've done really well.

Thank you for joining me for our learning today.