There are many uses of a bar magnet but to illustrate the wide range of uses, here are a few examples:
Bar magnets are used to highlight the magnetic field to children at school using iron filings.
As fridge magnets
Did you know – A fridge magnet has a magnetic field that is about 20 times stronger than the earth!?
Bar magnets are used within a car’s oil filter to help remove any ferromagnetic materials which could damage the engine. By doing this it makes the engine last longer.
Magnetic catches on doors to hold them shut.
They are used inside pickups in guitars to create different tones. The bar magnet is placed inside the pickup with a length of wire coiled around it to create a magnetic field. Whenever a guitar string vibrates in that magnetic field, the coil detects the changes and then creates a voltage, thus producing a perfect sound.