Diamagnetism is a form of magnetism that occurs in materials that do not have any unpaired electrons. When exposed to a magnetic field, these materials create a weak magnetic field in the opposite direction, causing them to be repelled by the magnet. This effect is generally very weak and is present in all materials, but it is most noticeable in substances like bismuth and copper. Unlike ferromagnetism, which can create strong magnetic fields, diamagnetism is a universal property of matter. It is temperature-independent and does not require any external energy to manifest. This phenomenon is often used in applications like levitation experiments, where diamagnetic materials can float above strong magnets.