The force that acts on an object inside a gravitational field.

The amount of matter (material) in an object.

The force per kilogram caused by a gravitational field.

The unit for gravitational field strength.

Gravitational force and weight

Science

Stretching springs

Hooke's law

Stretching rubber

The force of a floor

Levers

Turning forces

Floating, mass and shape

Pressure

Pressure at different depths and heights

In the Particle explanations of density and pressure unit, pupils will build on this knowledge to learn how the arrangement and movement of particles in solids, liquids and gases explain density, pressure, floating and convection.

In the Forces unit, pupils learnt how to accurately describe and explain the actions of forces in a range of situations.

This unit explores forces, deformation, Hooke’s Law, moments, and work done. It covers pressure in liquids, atmospheric pressure, upthrust, and equilibrium, as well as simple machines and force-extension relationships, highlighting how forces affect motion, friction, and object deformation.

Hidden forces

The extension of a spring is the change in length.

Masses will have a gravitational force that pulls them downwards.

Hanging masses (weights) can be used to put a known force onto a spring.

A mass hanger can be attached to a spring; adding masses to it causes the spring to stretch in a controlled way.

A line of best fit passes between a set of data points on a graph to show the pattern.

Variables are directly proportional when one is a constant multiple of the other.

A spring is elastic when it returns to its original length after forces are removed from it.

Hooke's law describes the behaviour of a spring when it is stretched.

The extension of a rubber band is its change in length.

A rubber band is elastic; it returns to its original length after forces are removed from it.

Rubber contains long molecular chains, that uncoil when it stretches.

A gravitational force acts on any object inside a gravitational field.

When an object rests on a surface, there will be a normal reaction force acting on it.

Materials are elastic if they return to their original shape when forces are removed from them.

The force between two electrically charged particles is an electrostatic force.

A lever is a simple machine designed to use the turning effect of a force.

The force applied to a lever is called the effort.

The force produced by a lever is called the load.

If a lever produces a larger load force than the effort force, it is a force multiplier.

A beam is balanced if it is not starting to rotate about its pivot.

One unit for the turning effect of a force is the newton-metre (N m).

Another unit for the turning effect of a force is the newton-centimetre (N cm).

The turning effect of a force is called a moment.

A force acting upwards due to pressure is an upthrust.

Water is displaced (moved) when an object floats on it or sinks in it.

A displacement can is used to find the volume of water displaced by objects when they float or sink.

If the density of an object is less than the density of water, it will float.

The effect of a force acting over an area.

When a force is concentrated on a small area the pressure is higher.

The standard unit for pressure, and this is also known as the pascal (Pa).

The pressure on a surface is the effect of a force acting over an area.

Depth is the distance under the surface of a liquid.

Atmospheric pressure is the pressure caused by the atmosphere, this decreases with height.

Hidden forces

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