What is friction?
Friction is a force that acts between two surfaces that are in contact with one another. The action of one surface sliding over another can slow down or even stop the movement between the two surfaces.
Friction KS2
Forces In Action - Lesson 2: Friction
This Forces in Action Year 5 Science scheme of work teaches your children how forces affect everything around us. They will learn about the effects of gravity, friction, air and water resistance as...
View more details
£2.99
Friction KS2
High and low friction
When an object moves across another surface, sometimes lots of friction (high friction) is created, and sometimes very little friction (low friction) is created. This depends on the materials that the two objects are made from, as well as their weight.
Examples of when high friction is caused:
- applying the brakes on a vehicle
- walking - the soles of your shoes on the pavement
- rubbing sandpaper on a rough wooden surface
Examples of when low friction is caused:
- skating on ice
- going down a slide
- sledging on snow-covered ground
The sled and the snow-covered ground are the two objects that are creating friction in this image.
Types of friction
Surface resistance
The friction between two solid objects that are in contact with one another.
Air resistance
The friction between the air and an object moving through the air.
Water resistance
The friction between the water and an object moving through the water.
How to measure friction
A forcemeter is used to measure forces. Forces are measured in units called newtons. Some forcemeters also have readings in grams as they convert the force to a weight. Forcemeters have a hook at the bottom to attach to the object being measured and a spring inside. The spring stretches as the force is applied to the hook. The reading can then be taken where the spring stops to see what the force measurement is.
Forcemeters are also known as newton meters. Forces, including gravitational forces, are measured in 'newtons' because Isaac Newton was the first man to explain gravity.
One way to test how much force is needed to move an object is to pull it with a forcemeter. The forcemeter will then show how many newtons of force it takes to get the object to move on the surface. The higher the friction between the object and the surface, the more newtons it will take to move it.
A diagram of a forcemeter pulling an object over a surface.
When should children learn about friction?
According to the National Curriculum Science objectives, children start to learn about friction in KS2. It is assigned as compulsory learning in Year 5 under the 'Forces' strand of learning.
Pupils should be taught to:
- identify the effects of air resistance, water resistance and friction, that act between moving surfaces
Friction, as well as other forces, are explored in our ready-to-teach Forces in Action Science scheme of work for Year 5.
