1. Year 7 Science
Forces

2. Electrostatic
Friction between objects can cause a build up of electric charge.
This build-up is called static electricity.
These forces are non-contact forces.
Positive charges attract negative charges
Like charges repel

4. Magnetic Forces

5. Magnetic Forces
The magnetism of a magnet is concentrated at the ends or poles of a magnet.
Magnets have a NORTH pole and SOUTH pole.
Like poles repel. Opposite poles attract.
North pole? South pole? Sound familiar?

6. Magnetic Forces A compass contains a small, lightweight magnet.
The north pole of the magnet will point North – no matter where you are on Earth.
What is attracting the magnet’s north pole?
In 1600, Sir William Gilbert suggested that…

7. The Earth is giant magnet!
North N S S N
East
West
South

9. Magnetic Forces
Earth’s magnetic field traps tiny charged particles (or ions) in a layer called the ionosphere.
These charged particles move towards the poles they are attracted to and produces coloured lights called auroras.

11. Magnetic Forces
The ionosphere is used to bounce off radio signals.