Perhaps you think that energy is something that can be fully used, exhausted. In the case of the machine, they would say that energy has passed from one form to another.

Law of energy conservation

This belief is based on the law of conservation of energy, which states that energy cannot be created from nothing and cannot be destroyed: it can only be transferred from one form to another.

This statement is equivalent to the fact that all the energy of the Universe was present in it from the very beginning and will remain as long as the Universe exists.

Potential and kinetic energy

Imagine a mountain lake. The lake communicates with the valley through a narrow gorge. This gorge is enclosed by a dam. The dam lock is closed and the water therefore cannot drain into the valley. If the gateway is opened, water will immediately flow, but when the gateway is closed, it stands still. In this case, they say that water has potential energy. That is, such energy, which has yet to be used.

But now the gateway is open, water gushed down, carried away by gravity. The gravity energy of water can turn into mechanical energy if a rotor of a power plant is placed in the path of water. Water does the work - it rotates the turbine. The potential energy of the water passed into kinetic energy - the energy of motion of the turbine.

The rotation of the turbine of a power plant causes the generator to generate electric current.That is, electric energy in the form of electric current comes to our homes and makes lamps burn, refrigerators and washing machines work. When you light a lamp, light (electromagnetic energy) and heat (thermal energy) arise.

Thus, the potential energy of the water did not disappear, but turned into light and heat in your home. Through walls and windows, the remnants of this energy are scattered in the Universe, but in no case disappear.