☯ Concept Cartoons ☯
Table of Contents
1 Chemistry Option A Magnets 9 - Electricity and magnetism
Have you talked about your ideas? Do you agree with any of the characters or do you think something different? Do you all have the same ideas? Here are some ways of finding out more. Use a textbook or the internet to find out about the discoveries of Hans Christian Oersted, William Sturgeon, Andre-Marie Ampere and Michael Faraday. Discuss how their discoveries help you to understand how electricity and magnetism might be connected. Which electrical devices do you have in your home that use magnets? How do electricity and magnetism work together in these devices?
Here’s what a scientist might say. Did you find any evidence to support or justify these ideas? Are there any questions that you still need to answer? Electricity and magnetism are closely connected. Motors, dynamos, generators and electromagnets all work because of this connection. Electricity can create a magnetic field, and magnetism can create an electric current. A wire with an electric current flowing through it has a magnetic field around it. If the wire is coiled up the fields add together and become stronger. If a soft iron core is put in the middle the magnetism is concentrated and becomes even stronger than before. When the electricity stops flowing, the soft iron stops being a magnet. Electric motors use coils of wire and magnets to make them move when a current passes through them. Generators work the other way, and use coils of wire and magnets to make electric currents when they are moved. Some devices like solar cells can make electricity without using a magnet, but most of our electricity comes from generators that use magnets or electromagnets. Draw a diagram to show what you think the electric circuit in an electric bell or a magnetic door lock is like. Share it with others. Do they agree?