64. Permanent and Induced Magnets

This video explains the distinction between objects that are magnets and objects that are simply made of magnetic materials, as well as the difference between permanent and temporary magnetism.

1. Magnetic Materials vs. Magnets

• Magnet: Any object that produces its own magnetic field.

• Magnetic Material: Any material that can be influenced by a magnetic field and has the potential to become a magnet itself.

• Key Elements (NCIS): The main magnetic elements to remember are Nickel, Cobalt, Iron, and Steel (an alloy of iron).

2. Permanent Magnets

• Definition: These magnets produce their own magnetic field all of the time.

• Example: A standard bar magnet.

3. Induced (Temporary) Magnets

• Definition: These are objects that only become magnets when they are placed in a magnetic field.

• The Process: When a magnetic material (like a piece of nickel or iron) is placed in the field of a permanent magnet, it "induces" a magnetic field in that material, creating its own north and south poles.

• Attractive Force: The force between a permanent magnet and an induced magnet is always attractive.

• Loss of Magnetism: Once the induced magnet is removed from the external magnetic field, it will lose its magnetism.

4. Magnetically Soft vs. Hard Materials

Materials differ in how quickly they lose their induced magnetism:

• Magnetically Soft Materials: Lose their magnetism very quickly (e.g., Iron, Nickel).

• Magnetically Hard Materials: Lose their magnetism much more slowly (e.g., Steel).

5. Summary Table