Properties of Materials: Choosing the Right Material

A chair, a window and a shoe are made of different materials: wood, glass, metal, cloth, plastic. Each material has its own properties. Let’s learn to describe materials, sort them, test them, and build new things from small pieces.

This lesson takes about 15 minutes. You can take a break after each part.

Before you start

Properties of Materials: Choosing the Right Material

Learning objectives

  • I can describe a material with words like hard, soft, shiny, flexible or transparent.
  • I can sort objects by a property and tell materials from nature from materials made by people.
  • I can test materials to find the best one for a job.
  • I can explain how an object made of small pieces can be taken apart and built into something new.

Describing materials

What is a property?

A property is something you can observe about a material: its color, its texture, whether it is hard or soft, shiny or dull, flexible (it bends) or stiff.

Six numbered boxes: 1, a hammer drives a nail into wood; 2, a hand squeezes cotton; 3, a shiny gold ring; 4, a pencil in a clear glass of water; 5, hands stretch a rubber band; 6, rough sandpaper next to smooth glass.
1 hard · 2 soft · 3 shiny · 4 see-through · 5 flexible · 6 rough or smooth.

Can light go through?

Light goes through a transparent material, like clear glass: you can see through it. A translucent material lets some light through, but things look blurry. An opaque material, like wood, stops the light.

A flashlight shines on three panels in a row: 1, clear glass; 2, frosted glass; 3, a wooden board. Light passes through the first, a little through the second, not through the third.
1 transparent: the light goes through. 2 translucent: some light goes through. 3 opaque: the light is stopped.

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Sorting materials

Sorting by properties

We can sort objects into groups by one property: all the hard objects together, all the soft ones together. One object can go into two groups: a drinking glass is hard and transparent.

From nature or made by people?

Some materials come from nature: wood from trees, wool from sheep, cotton from a plant, rock and sand from the ground. Other materials are made by people in factories, like plastic and glass. People make glass from sand heated until it melts.

Two trays. Green tray: wool, cotton, a rock, sand, a slice of wood and a silk cocoon. Blue tray: a plastic bottle, a glass jar, a metal spoon, a concrete block and a rope.
Green tray: materials from nature. Blue tray: objects made by people.
On the left, a flat sheet of glass and an arrow to a glass bowl. On the right, a wooden board and an arrow to a wooden chair.
People shape materials into objects: a sheet of glass becomes a bowl, a wooden board becomes a chair.

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The right material for the job

Testing materials

To choose a material, scientists test it. Which material is best to wipe up spilled water? Put the same amount of water in three dishes, add a sponge, a paper towel and a piece of plastic, and wait the same time. Then look: which one soaked up the most water?

A girl in safety glasses watches three dishes of blue water with a timer: a sponge, a paper towel and a piece of plastic.
Same water, same time: the sponge soaks up the most water; the plastic soaks up none.

Each part has its job

Look at a school chair. The seat is made of wood: it is hard and strong, so you can sit on it. The legs are made of metal: they are strong and hold you up. The feet are made of plastic: they do not scratch the floor.

A school chair with three numbered parts: 1, the wooden seat; 2, the metal legs; 3, the plastic caps on the feet.
Each part has its material: 1 a wooden seat to sit on, 2 strong metal legs, 3 plastic feet that do not scratch the floor.

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Building from small pieces

Many pieces, one object

Many objects are made of small pieces put together. A sneaker has a sole, a top, a lining and laces. You can take some objects apart, piece by piece.

A sneaker shown in separate pieces with numbers: 1, the rubber sole; 2, the blue cloth top; 3, the soft lining; 4, the lace.
A sneaker is made of pieces: 1 the sole, 2 the top, 3 the lining, 4 the laces.

Something new from the same pieces

With building blocks, you can build a house, then take it apart and build a boat. The pieces stay the same; only the shape of the object changes.

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Review game

Final assessment

To master the lesson, you need at least 60% correct answers.

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Summary

  • A property is something we observe: hard or soft, shiny or dull, rough or smooth, flexible or stiff.
  • Light goes through a transparent material, a little through a translucent one, and not through an opaque one.
  • Wood, wool, cotton and rock come from nature; plastic and glass are made by people.
  • We test materials, the same way each time, to choose the best one for a job.
  • Objects made of small pieces can be taken apart and built into new objects.

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