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Science Y3/Y4 – Forces – week 12

WHEELS, GEARS AND PULLEYS

Truth to Teach (Source)

To explore more ways of overcoming forces.

To discover that wheels have the advantage over rollers; they can be fixed to objects.

To learn about the history of the wheel.

To recognise the importance of gears which can be used to make things move slowly or quickly

To learn about pulley wheels

Way to Work (Means)

1. Review work covered on overcoming forces.

2. Talk about wheels helping us to overcome forces. Demonstrate how much easier it is to
pull a heavy load on a wheeled trolley or use a wheeled suit-case.

Let the children suggest as many objects which have wheels as they can. Talk about the
history of the wheel and the difference it has made to everyone. If possible, a display of
wheels could be set out. Discuss what wheels can be made of and which materials are
best for certain wheels. Let the children think of what sort of things are transported by
wheeled vehicles; which of their toys have wheels.

The wheel was invented 6000 years ago but the inventor is unknown. Wheels can be
made of wood, metal, rubber, plastic.

3. Show a set of plastic gears and ask the children if they know what they are and how they
work. Explain that gears can make things move faster or slower. Show an egg beater,
bike or clock with gear wheels and discuss how they work in that object. Later the
children may like to play with the plastic gears to see how many turns a large wheel
makes to a small one. If none are available they could make some card ones of their own.

4. Explain that pulleys are used to lift heavy loads. Show real pulley wheels, if possible, or a
picture of some, eg a crane. If pulley wheels are available, demonstrate that two wheels
are better then one.

5. Let the children complete the worksheet then try using the wheels and gears.

6. Share at the end of the lesson any discoveries they have made and review all the ways
that forces can be overcome.

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