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Basic 3 · Science · Earth Science

Impure Water and the Properties of Air

In this topic you will learn what makes water impure and describe the properties of air.

By the end of these notes you should be able to:

  • Name things that make water impure
  • Explain the dangers of impure water
  • Describe the properties of air

What you already know

  • Good drinking water (Basic 2)

Copy everything that has a blue line on its left into your notebook. The other parts are for reading.

Strand
Cycles
Sub-strand
Earth Science
Indicator
B3.2.1.4.1-2 – Identify things that make water impure and describe the properties of air

Introduction

Some rivers in Ghana have turned brown because of galamsey. Water with dirt, germs or chemicals is impure.

1. Impure Water

Things that make water impure
ThingExample
dirt and soilmuddy river water
germswater near toilets or rubbish
chemicalsmercury from galamsey, factory waste
rubbishplastic bags in gutters and rivers

Impure water can cause diseases like cholera and typhoid.

Sealed bottles of clear water and muddy water
Figure 1: Pure and impure water Draw a pure and an impure water sample.Illustration: Sirbus

2. Properties of Air

Properties of air
PropertyHow we know
air takes up spacea balloon gets bigger when blown
air has weighta full ball is heavier than a flat one
air moveswind blows trees
air pushes (pressure)air in tyres holds up a car

Safety: Do not taste or smell water samples in class.

New words

impure
Not clean; mixed with harmful things.
cholera
A disease spread through dirty water.
pressure
The push of air or water.
mercury
A harmful chemical used in illegal mining.

Summary

  • Dirt, germs, chemicals and rubbish make water impure.
  • Impure water causes diseases like cholera.
  • Air takes up space, has weight, moves and pushes.

Class activity: Water and Air Checks

  1. Look at the sealed water samples. Do not open them.
  2. Say which are impure and why.
  3. Blow up a balloon to show that air takes up space.

You need: Sealed local water samples in clear bottles, Clean cotton cloth, Inflated balloon

Exercises

Answer in your exercise book first, then check your answers.

  1. 1. Which makes water impure?

    • A. Germs
    • B. Sunlight
    • C. Air
    • D. Clean pipes
    Show answer
    Answer: GermsGerms cause disease.

  2. 2. Which disease is spread by dirty water?

    • A. Cholera
    • B. Malaria
    • C. Measles
    • D. Toothache
    Show answer
    Answer: CholeraCholera spreads through dirty water.

  3. 3. Air takes up space.

    • A. True
    • B. False
    Show answer
    Answer: TrueA balloon shows this.

  4. 4. Air has no weight.

    • A. True
    • B. False
    Show answer
    Answer: FalseA pumped ball weighs more than a flat one.

  5. 5. Not clean water is ______ water.

    Show answer
    Answer: impureThat is impure.

  6. 6. Give two properties of air.

    Show answer
    Answer: Any two: takes up space, has weight, moves, exerts pressure.These describe air.

Homework

  1. Ask an adult where your drinking water comes from and how it is kept clean.