Magnets and the Magnetic Field
How magnets, compasses and electric currents all share one invisible force field
Big Idea: A magnet creates an invisible magnetic field in the space around it. In 1820 Hans Christian Oersted discovered that an electric current also makes a magnetic field. This single fact links electricity and magnetism, and it is what lets us build electromagnets that we can switch on and off.
By the end you will be able to:
- name the two poles of a magnet and state the attraction / repulsion rule,
- describe a magnetic field with field lines and read Earth's field,
- explain Oersted's experiment and what it proved,
- describe the field of a straight current and of a coil (solenoid),
- explain how an electromagnet works and how to make it stronger.