Forces at KS3

A look at some ideas and activities involved in teaching

Forces at KS3

Objectives

• To identify key words and ideas at KS3• To explore practical activities where pupils can

experience and visualise forces both qualitatively and quantitatively

• To consider and evaluate class management of practical activities

• To develop clear procedures and rules for teaching pupils how to analyse forces and motion

• To consider how and where diagnostic questions can be used

Forces at KS1 and KS2

They will have learnt about pushes and pulls

forces produce movement

friction

forces of magnets

forces of springs

forces between Earth, Sun and Moon

balanced and unbalanced forces

Forces at KS3

Pupils should be taught:-• Force and linear motion

– Speed– Gravity and weight– Balanced and unbalanced forces– Frictional forces

• Force and rotation– Principle of moments

• Force and Pressure– Pressure = Force/Area– Applications of pressure

Introducing forces

• What do they already know?

• How do you engage pupils?

• Starter activities

• ‘Large demonstrations’

• Brainstorming

Direction of forces

• Force acts at point of contact (bit obvious, but not always recognised by pupils)

• Examples (lots and lots!)

Measuring forces

• Force-meter/newton-meter

• Measuring forces round the room

• Bathroom scales to measure your weight in Newtons

• Which leads us on to GRAVITY

Gravity

• How would you define ‘mass’ and ‘weight’?

• The force of gravity on every kg is 10N approximately here on the Earth’s surface

• Gravity makes things accelerate downwards all at the same rate (neglecting air resistance at this point)

• Gravity doesn’t affect forward motion

Friction

• Can divide this topic into friction between solid surfaces and in fluids

• Useful friction and friction as a nuisance

• What happens if there is no friction?

• Terminal velocity

• Experiments to remember

Forces and linear motion

• What do we mean by ‘balanced and unbalanced’ forces?

• Balanced forces = constant motion (or stationary)

• Unbalanced forces = changing motion

• Measuring speed

Forces and pressure

• Pressure = Force/Area

• Units?

• Demonstrating the effect of changing the area acted on

• Measuring pressure on the ground made by our feet

Turning forces or moments

• “Give me a lever and I can move the world”

• Clockwise and anticlockwise moments

• Examples of moments in action

Summary of forces topics

• Introduction to forces

• Direction and measuring forces

• Gravity

• Friction

• Forces and motion

• Forces and pressure

• Turning forces and moments