Energy Conversion

One of the reasons energy is hard to conceptualize is that it is constantly changing from one form to another.

This change between potential and kinetic forms of energy is called energy conversion.

During the conversion process, all the original forms of energy are turned into other forms of energy. Energy is always conserved.

Despite repeated investigations over nearly 200 years, no exception to this has ever been found.

As a result, scientists are confident enough in the conservation of energy principle that they refer to this as the First Law of Thermodynamics.

The First Law of Thermodynamics

The first law of thermodynamics states that the total energy of a system remains constant, even if it is converted from one form to another.

By extension, the following can be derived:

Energy can be neither created nor destroyed.
The amount of energy in the universe is constant.
Energy is always conserved through energy transfer and energy conversion.
There is no free lunch (you can't get additional energy).
It is impossible to build a machine that produces more energy than it uses (perpetual motion machine of the first kind).

Please watch this video:

An Energy Analogy

It is difficult to model this law. So we rely on analogies to help us visualize it.

Imagine you have a closed living room that contains a jigsaw puzzle and a curious cat.
The room represents the universe, and the completed jigsaw puzzle is an energy resource.
The cat jumps on the puzzle, scattering the pieces all over: in the corners, under couches, in drawers, and it probably chews on some too.
It might look like the puzzle pieces are gone or missing, but with careful searching, all the pieces can be found.

In our world, energy might appear to run out or get lost, but with careful examination, it is found to still exist.

It might have converted into different forms, such as heat or sound waves, but it is not lost.

Energy "Creation"

What about energy not being created?

We often talk about energy supply, development, production, and generation. All these involve converting one form of energy into another rather than energy being literally created.

On Earth, the incoming energy from the sun is in relative balance with the amount of heat loss from our planet.

This also holds true for the universe as a whole: it remains constant.

While energy is constant, its form and quality are continually changing.