Page 55 - Microsoft Word - SCI KS2 Y3 Y4 gs.doc

Science Y3/Y4 – Forces – week 11

SLOPES, ROLLERS AND LEVERS

Truth to Teach (Source)

Sometimes forces need to be overcome in daily life.

Heavy objects can be made to move more easily by slopes, rollers and levers.

Levers work by increasing the pushing force under an object so that a large load can be moved
with a small effort.

To learn about the fulcrum or resting point.

It is easier to move a heavy load on rollers than slide it along the ground.

Way to Work (Means)

1. Review this half term’s lessons.

2. Explain that whilst forces can be advantageous in daily life, we sometimes need to
overcome them. When we want to lift heavy loads, we have to overcome gravity.

3. Ask the children to work in groups or pairs to list ways of moving a heavy object which is
too heavy to lift. Specific situations could be used, eg a very heavy bag of garden
rubbish, a suitcase, a huge rock.

4. Gather back to share ideas.

5. Tie a heavy wheeled object/toy to a piece of rope. Ask a child to lift it with their little
finger. Lean a plank on a chair then ask the child to pull the same toy up the plank. Ask
which is easier. Establish that slopes help us to overcome forces. Think of examples in
daily life, eg a slope in a car-park, a winding mountain road. A gentle slope is better than
a vertical slope.

6. Ask another child to push a big book along a plank then contrast this with pushing it on
five parallel pencils on the plank. The pencils act as rollers. Rollers help us to overcome
forces too.

7. Give each pair of children a block and a ruler to set up something which will lift a book

easily. After a while gather the class back to discuss the best place for the ruler to rest
(fulcrum). It should be near to one end of the ruler. Explain that the ruler is acting as a
lever. Levers are used to lift heavy loads.

8. If time allows, the children could try the coin experiment. A ruler is balanced on a pencil
like a see-saw and a coin is placed on one end. The child drops the coin from a height of

53