What are waves and how do they propagate through different mediums?

Waves are disturbances that carry energy through a medium. They can be classified as mechanical waves, which require a medium to propagate, or electromagnetic waves, which can travel through a vacuum. Waves propagate through different mediums by transferring energy from one particle to another, causing a ripple effect that moves through the medium. The type of medium can affect the speed and behavior of the wave, with factors such as density and elasticity playing a role in how the wave travels.