Sharp solar panels installed on a roof
Energy is defined in physics as: ‘the property of matter and radiation which is manifest as a capacity to perform work’. The word has its roots in the Greek ‘energeia’, from ‘ergon’, meaning ‘work’.
But the word ‘energy’ has a much greater meaning than just something that supplies ‘work’ – just look at the way children often spend it, in fun, in joy, in running about senselessly. Although this hardly seems like ‘work’ – in a physical sense it is. It takes energy to lift a leaping child from the ground just as it does the space shuttle.
Modern quantum physics tells us that the entire universe is made of energy. It shows links between the energy that makes atoms circle electrons in a molecule and that which make planets circle suns in a solar system – it’s just a matter of scale.
Some even go further and postulate that everything is made of light energy – some, evidently more solid light than others. But physics is still unable to tell us whether light itself is a wave form or a particle – because it holds the properties of both.
So – if we live in a universe made of energy – why are we supposedly ‘running out’?
We are rather young as a species. Our non-renewable sources of energy such as oil, coal, natural gas and nuclear power are becoming scarce ( or too dangerous) just at the moment we have realised that everything is made of energy. We have been so stuck in a world of non-renewables that the groundwork on harvesting the infinite energy of the universe is still being done. Money and vested interest have their part to play in this slowed-down-process. Imagine – making us go out to work in jobs all day to pay for energy which is actually FREE and INFINITE and EVERYWHERE. What a shocker if people found out how to harvest their own!
There are many sources of renewable energy: wind, water, geothermal, solar, biomass, even natural electricity and hydrogen (secondary energy sources) –methods of harvesting them are getting easier – some people even make ‘harvesting devices’ for energy out of rubbish!
Energy is defined in physics in different ways. One type is called kinetic energy, the energy of a moving body. Another is called potential energy, which is energy possessed of a body by virtue of its position.
For example if I take a fish to the top of a high building and drop it – it uses kinetic energy to reach the ground. I go and fetch the fish and take it to an even higher building, and leave it there – hence giving it my energy. It now has potential energy – in fact more potential energy than it had at the top of the first building. And it smells more.
Then of course there is quantum energy. No fish here. In late 1900 Max Planck attempted to explain the idea of discrete energy. In Planck’s assumption radiant energy, known as ‘quanta’ is emitted in short bursts. Each of the bursts – called a ‘quantum’ – has energy E, that depends on the frequency ‘f’ of the electromagnetic radiation according to the formula:
E = h . f
H in this formula is Plank’s constant: 6.62618.10 –34 Js
So now you know !