What is energy?
Energy is the ability of a body to do work. We can also say that energy is ‘stored work’. Energy is never lost; it is converted from one form to another. Humans realized this hundreds of years ago and wanted to build perpetual motion machines-machines that keep moving without any input of energy. They have not succeeded ye. Today, we talk a lot about saving energy. This means efforts to be made to reduce energy consumption.
Is energy conserved?
Energy can neither be created nor be destroyed; it can only be converted from one form to another form. For instance, when we draw a bow, we u energy in it. this energy gets converted into the energy of movement called kinetic energy when we shoot the arrow. When you pick up a stone, you put energy in it. this energy called potential energy gets stored in it. if the stone falls down, it can do some work by hitting and damaging another object.
if energy is conserved why do we need to save energy?
Although energy is conserved we should try to save it. Every time energy is transferred or transformed, some of it is lost. Every time when some work is done, energy is released in the form of heat through friction. Although heat is a form of energy, we cannot use it to generate electricity or make a car go. Most of it gets radiated and is not available for use. For this reason, we need to save fossil fuels such as crude oil and coal, which are sources of energy and are scarce.
Where does all energy come from?
All energy on the Earth comes from the sun. Plants convert the energy from the sunlight into food substances through photosynthesis, and animals eat planets. Crude oil and coal formed from the remains of dead animals and planets store solar energy. Where does the sun get all its energy from? At the sun’s core, atomic nuclefuse together at extremely high temperatures. As a result of this fusion enormous radiation energy is released. Its energy seems to be unlimited. But this is not the case; our sun will die one day. We use its energy in the form of hydro or wind power,coal,crude oil, or bio-gas.