Materials and processing

Properties of materials, composites, alloys and how we process them. Read one part at a time and tap “I know this”. Then test yourself in the quiz.

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Properties

Property	Meaning	Example
Hard	Resists scratches and dents	Hardened steel for tools stays sharp
Strong	Carries a load without breaking	Steel beams
Elastic	Stretches and springs back	Rubber for tyres (and it grips well)
Transparent	You can see through it	Glass for windows
Density	How heavy it is for its size	Aluminium is light yet strong: aircraft
Insulator	Conducts heat poorly	Plastic handle of a pan

A natural material comes straight from nature (wood, wool, stone). Plywood is thin layers of wood glued together with the grain of each layer crossed at right angles: this makes it strong and stops it splitting or warping. Plastic left long in the sun grows brittle.

Wood, metal, plastic and composite materials.

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Sustainable choices

Sustainability: choose the material that harms the environment least.
Aluminium is very easy to recycle: it can be melted down again and again, and recycling it uses far less energy than making new aluminium from ore. A recyclable material reduces waste.
Test a material beforehand to make sure it suits the job.

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Remember this and test yourself

Remember this: your summary

First ask: what must the product do? Then choose the material.
Malleable: can be hammered into shape. Ductile: can be drawn into a wire. Brittle: breaks suddenly.
A composite combines materials to work better; an alloy is a metal mixed with another element.
Paint or galvanise metal to prevent rust.
Casting: molten metal into a mould. Welding: melts two pieces together. Finishing: sand, paint, varnish.

Write these points in your book. Read them again the night before the test.

Memory trick

Malleable = hit with a mallet into shape. Ductile = can be drawn out into a long thin wire, like copper wiring. Brittle = snaps like a biscuit.

Flash cards · Tap to turn over

Important words

First say what the word means, then turn the card over.

Test yourself · Part 2

True or false?

Read the question and the answer. Is the answer right? Tap True or False.

Now the real quiz!

The quiz has many more questions on this topic. Every question shows straight away whether you are right and explains why.

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For parents

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