I recently saw this video of a magnet swung against a copper slab and the magnet stops right in front of it. What happens there? Why?
A magnetic field = an electric field (kinda.) Play around with moving electrons and stationary protons in a wire, get a proton made apple, and then move that apple.What do you think will happen? The proton made apple will be pushed away by a force, that force’s strength is proportional to the apple’s speed and direction? What is that force? Magnetism.
When you get copper and magnet close to each other, the magnet moves electrons in the copper, since the magnetic field rotates, and magnetism basically=electricity,the electricity makes another magnetic field. This new field basically hates the magnet which makes an opposing force to it. Check out the [Lenz law.](http://(https://en.wikipedia.org/wiki/Lenz%27s_law))
Moving magnetic fields through a conductive object makes electricity. Moving electricity makes magnetic fields.
When you move a magnet close to a piece of copper, it moves the electrons in that copper around, making electricity. Since the magnetic field is moving, the electricity moves too, making its own magnetic field. [This magnetic field repels the magnet, creating a force that opposes the movement of the magnet.](https://en.wikipedia.org/wiki/Lenz%27s_law)
[The typical demonstration drops a magnet down a piece of copper tubing.](https://www.youtube.com/watch?v=H31K9qcmeMU)