# Resource 6: More ideas for experiments around forces

Teacher resource for planning or adapting to use with pupils

1. Using springs to measure forces:

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• a.Make a class list of everything the pupils have seen that includes a spring.
• b.Show how a spring stretches with a pulling force and measure how much it stretches.
• c.Use a spring to measure forces around the classroom – measure how much the spring changes in length. (You can make a spring from a 50 cm length of copper wire or you can use a strong elastic band instead of a spring.) Some forces to measure include door opening, pulling a chair along the floor, pulling a pen or pencil, opening a clothes peg.

2. Cutting down friction in water – making streamlined shapes:

Ask pupils to draw the shapes of fish, boats and diving birds. Which sort of shape is best for going fast through air or water?

Pupils make different shapes with lumps of clay or plasticine. Drop these shapes through a tall tank of water and time how long it takes each to get to the bottom.

3. Forces at a distance:

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• a.Use a magnet to pick up steel pins. Ask pupils to slowly move the magnet towards the pins. What is the distance between them when the pins first start to move?
• b.Rub a plastic pen or ruler on a cloth (e.g. a duster). This gives the pen or ruler an electric charge. Now try to use the pen or ruler to pick up small pieces of scrap paper. How many will it pick up?

Ask pupils to explain what they think is happening in each of these experiments.

4. Forces and weight:

Weight is a special sort of force caused by the Earth attracting everything on it or near it.

Ask pupils to use a spring or elastic band to make a weighing machine that measures the pull of the Earth on objects. They will need to make a scale for it.

Then talk to pupils about how the weight of these objects would be different on other planets in the solar system or on the moon. Larger planets exert a larger force on another object and smaller planets or bodies exert a smaller force.

Resource 5: How can we reduce friction?

Acknowledgements