1. A magnet has magnetism, which is its most obvious characteristic.

The Application of Neodymium Iron Boron Magnets in Speakers

2. A magnet can attract iron nails in a magnetic field because its molecular arrangement is opposite to the direction of current flow.

When a wire passes through the center (or poles) of a magnet, an induced electromotive force is generated.

When two mutually repelling objects come close to a certain extent, relative motion occurs between them.

5. The compass can be used to determine direction and distance. The working principle of a compass is to deflect the pointer based on the force of the geomagnetic field on the current

6. An alternating electromagnetic field is generated in an energized solenoid, which can cut and vibrate metal to produce sound. (Electromagnetism phenomenon: The phenomenon of a changing magnetic field around a conductor that causes a voltage difference between the two ends of the conductor due to the action of Lorentz force.)

7. The Earth is a huge natural generator - the Sun is a huge battery.

People can use solar energy to generate electricity and provide electricity for some electrical appliances. (Working principle of solar panels: When light shines on semiconductor materials, photons are absorbed by photosensitive materials to produce electron hole pairs; when an applied voltage is applied, electrons escape from the holes and form free electrons with positive charges; after the applied voltage disappears, these free electrons return to the semiconductor surface from the external circuit and become charge carriers)

Mercury is a poor conductor of heat and can be used as a thermometer, thermometer, and alarm.