Can we store work – What is Energy?

LEARNING OBJECTIVE 3.4.A -Describe the energies present in a system.

In the last section, we learned to calculate Work in different scenarios. Work makes things happen. The next question is can we somehow store the work for future use, If so how? Once stored we will probably also need to transport it, which will allow us to use it wherever we need as well as whenever we need it. This is the main question we will address in this section.

Simple machines allow us to transfer work done in one part to another part, without any loss. If we have a lever which is 10 m long, we can then use it to transfer work done at one end of it to the other end. The amplification of force is of course an enormous advantage in as transmission of work from one place to another. Can we build a machine which will allow us to use the work at a much more distance let’s say 1 km from the point of origination or maybe 100 km from the point of origination? If so that will be wonderful. Surely we can build an enormous lever of 1 km long but whenever we wish to use the same we will also need to transport our lever to another place. So the second obvious question is how do we transport work beyond the capabilities of simple machines.

The quest to answer this question lasted for several years. It was the German philosopher and scientist Gottfried Wilhelm Leibnitz (1646-1716), who was the first to get a clear notion of work in the physicist’s sense. He observed that any living creature stores work and is able to call upon and use it when needed. After all, we humans can use our hands and legs to do some work in the physical sense, like applying force to move some object. Leibnitz suggested that something called “work-store” might have seemed to be particularly associated with life, since living things seemed filled with this capacity to do work, whereas dead things, for the most part, lay idle and did not work.

However, it is clearly wrong to assume that work is stored only in living things; as a matter of fact, the wind can drive ships, running water can turn turbines, and in both cases, force is being exerted through a distance. Work, then, was obviously stored in non-living objects as well as in living ones. In 1807, the English physician Thomas Young (1773-1829) proposed the term energy for this work-store. This is from Greek words meaning “work-within” and is a purely neutral term that can apply to any object, living or dead.

This term gradually became popular and is now applied to any phenomenon capable of conversion into work. There are many varieties of such phenomena and therefore many forms of energy. We we now look at different kinds of energies in the next section.

Energy: An ability to do work.

What is energy?