Eli5: what exactly is energy?

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Like, i know it’s the ability to do work and all that, but this isn’t what energy is, it’s what energy does. What IS energy tho?

In: Physics

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Simply put, energy is the ability to effect change. There are a lot of ways that manifests, and a lot of complicated descriptions for how it works, but it isn’t a thing, any more than knowledge is a thing.

When an object moves, that movement is energy. When that object hits another object, it will transfer some of that energy to the other object, and change how it moves. There may also be sound (other movement), heat (molecules within things moving faster), and light (which deserves its own ELI, as things moving as fast as light does start to have weird interactions with time).

When you put clothes in the dryer, and they come out stuck together, and they crackle a bit when you pull them off, it’s because some clothes have transferred electrons to other clothes, resulting in electricity, which is energy related to the movement of electrons.

Just as motion isn’t a thing you can touch, so is energy not a thing you can touch. Rather, it’s a measurement of how much one thing can change other things.

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