What is a disturbance that carries energy?

Answer 1

A rhythmic disturbance that carries energy would be called a mechanical wave. A sound wave or a blast wave (or even a seismic wave) qualifies as a rhythmic disturbance. (Later with the light, okay?) Sound - or any of those other waves - involves the compression and rarefaction of air (or another fluid) or a solid, to transmit the harmonic motion. Let's look at, say, a vibrating guitar string. The string oscillates in air, and the rhythmic motion of the string as it moves back and forth creates sound. The string actually compresses the air in front of it an creates a little "mini-vacuum" behind it as it's moving forward. That space behind the string is rarefied air. The string is moving fast enough that the zillions of tiny air atoms and molecules can't instantly fill in behind that string. A blast wave from an explosion or a seismic wave works the same way. Also, there are different mediums through which the energy is going to be transferred. The medium conducts the energy. The energy is actually transferred into the medium in order to travel through it. Electromagnetic energy may not qualify to be part of this answer under the description set down in the question. The word "disturbance" suggests a medium through which the energy is propagated. Electromagnetic energy, like radio waves or light for instance, require no medium through which they must be transmitted for them to propagate. And as far as light creating "a rhythmic disturbance that carries energy" being true, think about it and come to your own conclusion. Certainly light can move through air or other media, and it interacts with the media, too (losing energy as it does). But a bit of a debate might ensue as to whether or not something like light is actually a "disturbance" as was asked. Light is moving energy - electromagnetic energy. Make no mistake about that. But if light is moving through deep space, what is the "disturbance" involved? Does it have something to do with spacetime?

Answer 2

A wave is a disturbance that carries energy through a medium or empty space. It transfers energy without transferring matter. Examples include electromagnetic waves (like light) and mechanical waves (like sound).