"Waves" of heat can be seen above a hot stove element. This is an example of:

The appearance of "waves" of heat above a hot stove element is an example of refraction. Refraction occurs when light or other waves pass through different media at varying densities, causing them to change speed and direction. In this case, the hot air heated by the stove is less dense than the cooler air surrounding it. As light waves travel through these layers of air with different temperatures and densities, they bend, creating the visual effect of waves or shimmering distortions above the heating element. This phenomenon effectively illustrates how temperature differences can influence the path that light takes, leading to the visual illusion associated with heat.

The other concepts do not apply to this situation: diffraction refers to the bending of waves around obstacles or through openings, reflection pertains to the bouncing of waves off surfaces, and convergence involves the coming together of waves rather than their bending due to differences in medium.