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The Three Laws of Energy

by Gordon Ettie

“Energy is not lost or destroyed, it is merely transferred from one party to the next.” – Sir Isaac Newton


In a discussion of energy the basic understanding revolves around the fact that there are three laws.  These are simple laws dealing with energy and can be defined as follows:

First Law

Energy can neither be created nor destroyed.  This means that you can’t make energy out of nothing— the total amount of energy in the universe is a constant. (Please note that this applies to a closed system – the Earth is not a closed system, the Earth receives energy all the time from the Sun).

Second Law

The second law refers to the state of energy and is reflected in a measurement of the degree of disorder, (a measurement called entropy).  When you burn a lump of coal, (a material in a very ordered state) a change occurs which results in a more disordered state and you can never combine the resultant products, (heat, gases, etc.) back to form that original lump of coal, (First Law).  The Universe, according to scientific evidence, is winding down, the sun will eventually go out, (in billion of years so we don’t have to worry right now).  In summary when we use an energy source it is not destroyed but enters a more disordered state.  This makes the energy less available to us and in converting the energy to power means some loss.

Third Law

As we mentioned the universe is winding down.  The third law is that everything does come to a stop only when the temperature is at −273.15°C on the Celsius scale. This equates to −459.67°F.  This is called absolute zero and is where the entropy measurement is 0, (Zero).

Together, these laws help form the foundations of modern science. These laws are absolute physical laws – everything in the observable universe is subject to them. Like time or gravity, nothing in the universe is exempt from these laws.


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