What is Energy?

Energy is a big concept.

We cannot see energy nor can we touch it or hold it in our hands, and yet according to Einstein's e=mc² anything in the universe can be thought of as a form of energy.

Energy exists in many forms and can change between these forms. When this happens we say that energy has been converted or transformed from one form to another. Though it may change from one form to another, energy cannot be created or destroyed. This is called the conservation law of energy.

Simply put, energy is a concept used to explain changes that we observe. If ever we see a change, then we know that energy was involved. For example, when an ice-cream melts - heat energy was involved. When a light bulb glows - electrical (and heat and light) energy were involved.

Another way of thinking about energy is to understand that when something is pushed or pulled a force is applied to an object. When this happens, we can say that work is done on that object. The amount of energy required to do the work is measured in joules.

watt = joule per second

There are many forms of energy that are either kinetic or potential energy.