Waves were central to the advancement of modern science. Although most people will only be familiar with waves made in water, they are also present in surprising places.
In 1861, James Maxell discovered that light, electricity and magnetism were all manifestations of the same phenomenon, described by the same equations that described waves. Hence, light is actually composed of waves.
Here is a simple wave parameterized by amplitude and angular frequency. Move your mouse vertically to change amplitude, and horizontally to change angular frequency.