---
title: "What Things Are Made Of"
book: "School Chemistry — Grades 1 to 12"
subject: chemistry
language: en
chapter: 1
exercises: 11
source: https://one-course.com/books/chemistry/1/en/chapter/1-what-things-are-made-of
license: CC-BY-NC-SA-4.0
credit: "One Chemistry Book, One Course (one-course.com)"
---

# Chapter 1 — What Things Are Made Of

Look at a breakfast table. There is a spoon, a glass of milk, a fork, a napkin, a bowl, and a jumper hanging on the back of a chair. That is many things, and each one is made of something: the spoon of wood, the fork of metal, the glass of glass, the napkin of paper, the bowl of plastic, the jumper of wool. A table full of things, made of only a handful of different stuffs. This chapter is about those stuffs.

![A breakfast table: many objects, made of a few materials.](https://one-course.com/images/onecourse/chapters/chemistry-1/g1-materials-around-us/img-bb28e6137d5a.jpg)

*A breakfast table: many [objects](#def-g1-materials-around-us-object), made of a few [materials](#def-g1-materials-around-us-material).*

## 1.1 Objects and materials

**Definition 1.1 (Object).**

An *object* is a thing we can see and touch, and often hold and use: a spoon, a chair, a ball, a window, a shoe.

**Definition 1.2 (Material).**

The *material* of an [object](#def-g1-materials-around-us-object) is what the [object](#def-g1-materials-around-us-object) is made of. A spoon can be made of wood, of metal or of plastic: the spoon is the [object](#def-g1-materials-around-us-object), the wood is the material.

**Example 1.3 (One object, three materials).**

Three spoons lie side by side. They have the same shape and do the same job, so they are the same kind of [object](#def-g1-materials-around-us-object). But one is made of wood, one of metal and one of plastic: three different [materials](#def-g1-materials-around-us-material).

![Three spoons: the same object, three materials — wood, metal and plastic.](https://one-course.com/images/onecourse/chapters/chemistry-1/g1-materials-around-us/img-f3b274274fe9.jpg)

*Three spoons: the same [object](#def-g1-materials-around-us-object), three [materials](#def-g1-materials-around-us-material) — wood, metal and plastic.*

**Example 1.4 (One material, many objects).**

Wood is the [material](#def-g1-materials-around-us-material) of a pencil, a chair, a door, a toy train and a wooden spoon. Many different [objects](#def-g1-materials-around-us-object) can be made of the same [material](#def-g1-materials-around-us-material).

**Remark 1.5 (Objects made of several materials).**

Many [objects](#def-g1-materials-around-us-object) are made of more than one [material](#def-g1-materials-around-us-material). A pair of scissors has blades of metal and handles of plastic. A pencil is wood outside and a grey stick of graphite inside. A window is glass in a frame of wood, metal or plastic.

## 1.2 Seven common materials

**Proposition 1.6 (Materials all around us).**

Most of the [objects](#def-g1-materials-around-us-object) around us are made of a few common [materials](#def-g1-materials-around-us-material):

- **wood** : tables, chairs, pencils, doors;
- **metal** : forks, keys, nails, pans, bicycles;
- **glass** : windows, jars, bottles, glasses;
- **plastic** : bowls, bottles, toys, buckets;
- **paper** and card: books, napkins, boxes;
- **fabric** : clothes, curtains, bags — made of wool, cotton or other threads;
- **stone** : walls, steps, pebbles, statues.

![Seven samples, from left to right: wood, metal, glass, plastic, paper, fabric (wool) and stone.](https://one-course.com/images/onecourse/chapters/chemistry-1/g1-materials-around-us/img-c5e289b5481d.jpg)

*Seven samples, from left to right: wood, metal, glass, plastic, paper, fabric (wool) and stone.*

**Remark 1.7 (Names that are also materials).**

We call a drinking glass “a glass” because it is made of glass, and a sheet of paper “a paper”. The word for the [object](#def-g1-materials-around-us-object) and the word for the [material](#def-g1-materials-around-us-material) are then the same. When we speak of [materials](#def-g1-materials-around-us-material), we mean the stuff, not the [object](#def-g1-materials-around-us-object).

## 1.3 Properties of materials

**Definition 1.8 (Property of a material).**

A *property of a material* is something we can find out about it by looking, touching or testing: is it hard or soft? Can we see through it? Does a magnet pull it? Does it float on water or sink?

**Example 1.9 (Hard and soft).**

A pebble is hard: pressing it with a thumb leaves no mark. A wool scarf is soft: it bends and folds in the hand. Wood, metal, glass and stone are hard; fabric and paper are soft and bend easily.

**Example 1.10 (Seeing through).**

We can see the garden through a window: glass lets light through, we say it is *transparent*. We cannot see through a wooden door, a brick wall or a metal pan. Some plastics are transparent, like a water bottle; others are not, like a red toy brick.

**Example 1.11 (Attracted by a magnet).**

A magnet pulls a steel paper clip, a steel nail or an iron key towards it. It does not pull wood, glass, plastic, paper, fabric or stone. And, surprisingly, it does not pull every metal: a drink can of aluminium and a copper wire stay where they are. A magnet attracts [objects](#def-g1-materials-around-us-object) made of iron and of steel, which is mostly iron.

![A magnet lifts steel paper clips. The aluminium can and the copper disc on the table stay where they are.](https://one-course.com/images/onecourse/chapters/chemistry-1/g1-materials-around-us/img-9e65eb31450c.jpg)

*A magnet lifts steel paper clips. The aluminium can and the copper disc on the table stay where they are.*

**Example 1.12 (Floating and sinking).**

Put a few [objects](#def-g1-materials-around-us-object) in a basin of water. A wooden block and a plastic bottle cap float. A pebble, a glass marble and a steel nail sink to the bottom. Whether a thing floats or sinks is also a property of its [material](#def-g1-materials-around-us-material).

![In a basin of water: the wooden block and the plastic cap float; the pebble, the glass marble and the steel nail sink.](https://one-course.com/images/onecourse/chapters/chemistry-1/g1-materials-around-us/fig-a85c9b9383f1.svg)

*In a basin of water: the wooden block and the plastic cap float; the pebble, the glass marble and the steel nail sink.*

## 1.4 Sorting materials

**Method 1.13 (Sorting by one property).**

To sort a pile of [objects](#def-g1-materials-around-us-object):

1. choose **one** question, for instance “Does a magnet pull it?”;
2. test each [object](#def-g1-materials-around-us-object) and put it in the “yes” group or the “no” group;
3. then, if you wish, sort each group again with another question.

One question at a time: that way every [object](#def-g1-materials-around-us-object) has exactly one place.

![Two questions, two hoops. Inside the blue hoop: the objects made of metal. Inside the orange hoop: the objects a magnet pulls. In both hoops: the objects of iron or steel. Outside both: everything else.](https://one-course.com/images/onecourse/chapters/chemistry-1/g1-materials-around-us/fig-ec0726b1083d.svg)

*Two questions, two hoops. Inside the blue hoop: the [objects](#def-g1-materials-around-us-object) made of metal. Inside the orange hoop: the [objects](#def-g1-materials-around-us-object) a magnet pulls. In both hoops: the [objects](#def-g1-materials-around-us-object) of iron or steel. Outside both: everything else.*

| [object](#def-g1-materials-around-us-object) ([material](#def-g1-materials-around-us-material)) | hard? | see-through? | pulled by a magnet? |
| --- | --- | --- | --- |
| block (wood) | yes | no | no |
| nail (steel) | yes | no | yes |
| marble (glass) | yes | yes | no |
| bottle cap (plastic) | yes | no | no |
| sheet (paper) | no | no | no |
| scarf (wool) | no | no | no |
| pebble (stone) | yes | no | no |

## 1.5 The right material for the job

**Proposition 1.14 (Each material is chosen for its properties).**

People choose the [material](#def-g1-materials-around-us-material) of an [object](#def-g1-materials-around-us-object) for what the [object](#def-g1-materials-around-us-object) must do:

- a window must let light in: it is made of glass, which is transparent;
- a raincoat must keep the rain out and fold up: it is made of plastic or of a fabric that water cannot pass through;
- a pan must not melt on the cooker: it is made of metal;
- a pan’s handle must not burn the hand: it is often made of wood or of a hard plastic, which do not get as hot as metal;
- a pillow must be soft: it is made of fabric filled with feathers or fibres.

**Example 1.15 (A boat).**

A toy boat must float. It can be made of wood or of plastic. A boat made of a solid lump of stone would sink at once.

**Remark 1.16 (Broken glass).**

Glass is hard but it breaks, and its pieces are sharp. When a glass breaks, an adult picks up the pieces.

## 1.6 Exercises

**Exercise 1.1 ★.**

Is a chair an [object](#def-g1-materials-around-us-object) or a [material](#def-g1-materials-around-us-material)? Is wood an [object](#def-g1-materials-around-us-object) or a [material](#def-g1-materials-around-us-material)?

**Solution of Exercise 1.1.**

A chair is an [object](#def-g1-materials-around-us-object). Wood is a [material](#def-g1-materials-around-us-material): a chair can be made of it.

**Exercise 1.2 ★.**

Name the [material](#def-g1-materials-around-us-material) of each [object](#def-g1-materials-around-us-object): a window pane, a nail, a pebble, a book, a sock.

**Solution of Exercise 1.2.**

Window pane: glass. Nail: metal. Pebble: stone. Book: paper. Sock: fabric (wool or cotton).

**Exercise 1.3 ★.**

Give two [objects](#def-g1-materials-around-us-object) made of wood and two [objects](#def-g1-materials-around-us-object) made of plastic.

**Solution of Exercise 1.3.**

Wood: a pencil, a door (or a chair, a table). Plastic: a bowl, a bucket (or a toy, a bottle).

**Exercise 1.4 ★.**

Find the odd one out, and say why: a wooden spoon, a metal fork, a plastic spoon, a wooden chair. (Look at the [materials](#def-g1-materials-around-us-material).)

**Solution of Exercise 1.4.**

The metal fork: it is the only one not made of wood or plastic. (Two are made of wood and one of plastic.)

**Exercise 1.5 ★.**

Which [material](#def-g1-materials-around-us-material) can we see through: wood, glass or stone?

**Solution of Exercise 1.5.**

Glass: it is transparent.

**Exercise 1.6 ★.**

A magnet is held near a steel nail, a glass marble and a wooden block. Which one does it pull?

**Solution of Exercise 1.6.**

The steel nail. A magnet pulls iron and steel, not glass or wood.

**Exercise 1.7 ★.**

Look at the figure with the basin. How many [objects](#def-g1-materials-around-us-object) float? How many sink?

**Solution of Exercise 1.7.**

Two [objects](#def-g1-materials-around-us-object) float (the wooden block and the plastic cap); three sink (the pebble, the marble and the nail).

**Exercise 1.8 ★.**

A pair of scissors has blades and handles. Which [material](#def-g1-materials-around-us-material) is each part made of? Is a pair of scissors made of one [material](#def-g1-materials-around-us-material) or of two?

**Solution of Exercise 1.8.**

The blades are metal, the handles plastic. The scissors are made of two [materials](#def-g1-materials-around-us-material).

**Exercise 1.9 ★.**

Look at the figure with the two hoops. In which hoop is the drink can? Why is it not in the orange hoop?

**Solution of Exercise 1.9.**

In the blue hoop: it is made of metal. It is not in the orange hoop because a magnet does not pull it: it is made of aluminium, not of iron or steel.

**Exercise 1.10 ★★.**

Why are windows made of glass and not of wood?

**Solution of Exercise 1.10.**

A window must let light in, and we must see through it. Glass is transparent; wood is not.

**Exercise 1.11 ★★.**

Sam wants to sort these 8 [objects](#def-g1-materials-around-us-object) with the question “Does a magnet pull it?”: a steel nail, a paper clip, a pebble, a wooden spoon, an iron key, a drink can, a glass marble, a wool sock. How many [objects](#def-g1-materials-around-us-object) go in the “yes” group? How many in the “no” group?

**Solution of Exercise 1.11.**

“Yes”: the nail, the paper clip and the key, 3 [objects](#def-g1-materials-around-us-object). “No”: the pebble, the spoon, the can, the marble and the sock, 5 [objects](#def-g1-materials-around-us-object). $3 + 5 = 8$: every [object](#def-g1-materials-around-us-object) has its place.