How much do you know about magnetism and electromagnetism?
The Earth itself is a large magnet. The inner and outer core are made of metal, mostly iron, with some nickel. The outer core is a liquid, while pressure keeps the inner core solid. Heat, and the Earth’s spin ensure the liquid outer core is constantly moving. Consequently, electrical currents occur in the core, creating a magnetic field. This magnetic field extends into space, generating a magnetic field around the planet. This means the Earth has a north magnetic pole, and a south magnetic pole.
Not only does this allow us to use magnetic compasses to navigate, but the magnetic field also protects us from the Sun. It deflects solar winds (charged particles from the Sun), defending us against harmful gases and the charged particles which would destroy the atmosphere.
The strength of the Earth’s magnetic field changes. The magnetic North Pole has been moving faster than ever recently. A hundred years ago it was in Arctic Canada, but is moving eastwards towards Asia. The poles can switch places. At the moment, the north pole of a compass needle points towards the top of the Earth. That means that our North Pole must be acting as a South magnetic pole as opposites attract. However, in the past, the top of the Earth has been a North magnetic pole. There have been almost 200 pole switches in the last 100 million years!
GCSE scientists – you need to be able to describe how magnets and electromagnets work. For help, try our new guide “How to work with Magnetism and Electromagnetism”. It includes information about magnetic fields and the uses of permanent and induced magnets. There is also an explanation of how electromagnets work, and the motor effect. As always there are questions to try, and answers to check your understanding.
Click on the picture below to see the guide.
If you found this useful and think you would benefit from some additional help, please contact us.
