In what way can an object become magnetized?

An object can become magnetized by being struck with a magnet because this process involves the alignment of the magnetic domains within the material. When a magnet strikes or comes into contact with a ferromagnetic material, such as iron, the magnetic fields of the magnet influence the magnetic domains within the material, causing them to align in the same direction. This alignment turns the previously unmagnetized object into a magnet itself, allowing it to exhibit magnetic properties and attract other ferromagnetic materials.

Other methods, such as heating an object, can disrupt the magnetic domains instead of aligning them. Dropping an object on the ground or placing it in water does not provide the necessary conditions for magnetization and generally does not influence the magnetic properties of the material in any significant way. Therefore, striking a magnet is the effective means of inducing magnetism in an object.