Yeah, so it relies a lot on I suppose gravitational potential energy.

对，我认为主要借助于重力势能。

This stores the energy by giving the water extra gravitational potential energy.

这通过给水额外的重力势能来储存能量。

One common type of potential energy is gravitational potential energy

最常见的势能类型之一 它是引力势能。

Once the book hits the ground, though, we'd say that its gravitational potential energy

但书一落地， 我们说它的引力势能为零。

If I hold this book a meter above the ground, we'd say that it has gravitational potential energy.

如果你把这本书放在一米以上的高度 地球，我们说有引力势能。

If we move them further away, or opposite the direction of the gravitational force, we increase their gravitational potential energy.

如果我们将它们移得更远，或者与重力方向相反，我们就会增加它们的重力势能。

Gravitational potential energy is the potential energy that an object with mass has due to the force of gravity from another object with mass, like say, the Earth.

重力势能是一个具有质量的物体由于来自另一个具有质量的物体（例如地球）的重力而具有的势能。

Moving it to a higher shelf would mean it has gravitational potential energy relative to that lower shelf, or relative to the floor if we want to use that as our comparison instead.

将其移至较高的架子意味着它相对于较低的架子具有重力势能，或者如果我们想用它作为比较的话，则相对于地板具有重力势能。

Calculating gravitational potential energy is easy enough