The wave is a form of disturbance which transmits energy from one place to another without the actual flow of matter as a whole. Wave motion is a form of disturbance which is due to the repeated periodic vibrations of the particles of the medium about their mean positions and the motion is handed over from one particle to another without any net transport of the medium. Water waves or sound waves are called mechanical or elastic waves as they require a material medium for their propagation which possesses elasticity as well as inertia. Light waves are electromagnetic waves or non-mechanical waves which can propagate through vacuum i.e. don’t require any material medium.Matter waves are associated with moving electrons, protons, neutrons and other fundamental particles and even atoms and molecules and all these constitute the matter, so are called matter waves. Matter waves arise in quantum mechanical description of nature. Thus, waves are of three types: Mechanical waves, electromagnetic waves and matter waves. Mechanical waves are of two types; transverse waves and longitudinal waves. A wave is said to be progressive or travelling wave if it travels from one point of the medium to another.