How are a bar magnet and a electromagnet different

An electromagnet acquires magnetism through electricity.
A bar magnet comes with magnetism already stored within it and doesn't need to rely on on another object for power.

  An electromagnet is made from a coil of wire which acts as a magnet when an electric current passes through it.  Often an electromagnet is wrapped around a core of ferromagnetic material like steel, which enhances the magnetic field produced by a coil.