Year 4 Science

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Help the Environment to Make the World a Better Place


Pollution Harms Us All

Have you ever smelt the exhaust coming out of a lorry or bus? Have you ever seen thick smoke pouring from a factory's chimney? Exhaust and smoke often contain harmful chemicals that pollute the air. To 'pollute' means to make something dirty or impure or unsafe. Cars, lorries and some buses are one cause of air pollution. Their engines burn fuel, usually some petrol or diesel oil. From their exhaust pipes these vehicles put out harmful emissions. (Emissions are what cars and other vehicles put in the air as a result of burning fuel in their engines.)

Now imagine a city full of cars, lorries and buses, every one of them burning fuel and releasing emissions. When city air gets so dirty that the sky starts looking brown, it is called smog, a word made from the two words 'smoke' and 'fog'. If people breathe in too much smog, it can damage their lungs. When London experienced bad smog in the 1950s, the law was changed to stop people burning so much fuel with bad emissions, especially coal for heating. We don't ever want our cities to get that bad again.

Water can also become polluted. Whenever people litter and don't put their rubbish in the bins then this litter can be swept by rain into rivers and lakes so that it pollutes the water and makes the water dangerous to drink. In the past, factories could pollute water by dumping chemicals and waste products into lakes and rivers. Now there are careful limits in the UK about how much is safe.

In Year 3 we learnt about the water cycle. If water evaporates into polluted air, the water that comes down as rain and flows into rivers and lakes can also become polluted by the air. That's another reason why it's not safe to drink water straight from rivers and lakes.

Conservation and Recycling

You can help fight pollution. Do you have any ideas how?

One way is by conserving, which means using something carefully and not wasting it. When you don't leave the bathroom tap dripping, you are conserving. Lights, computers and televisions use electricity, and electricity is often made by power stations that burn fuel and send emissions into the air. When you turn off the lights and the television when you're not using them, you are conserving, and you're helping to fight pollution.

Are you practising conservation at home or school? For example, do you recycle? When you recycle something, it will be used again.

Recycling can help reduce water and air pollution. If you recycle glass and aluminium containers, for example, factories won't have to burn as much fuel to make new containers. If a factory burns less fuel, it produces fewer unwanted chemicals at the same time.

Lots of stuff can be recycled: aluminium cans, tin cans, glass bottles, plastic bottles, cardboard, newspapers, even junk mail. Look out for the recycling symbol to tell you which items can be recycled. This symbol also reminds us that, instead of throwing things away, we can use them (or the materials they are made from) again. Recycling helps make sure we don't use up what nature has to offer.

Since living things depend on each other, what will you do as a human to make the environment better for all living things and people, too?

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