Energy in nature comes in many different forms.Heat is a form of energy.A lot of heat energy comes from the sun .Heat can also come from a forest fire or,in much smaller puantities,from the warm body of an animal. Light is another form of energy. It also comes from the sun and from the stars .Some animals and even plants produce small amounts of light energy.Then there is electricity,which is yet anothe sort of energy.
All these different forms of energy can be changed,one into another.Think of lightning.When lightning flashes.all the electrical energy stored in the clouds immediately changes into light which you can see,into heat which burns whatever is struck by the lightning,and into sound which you can hear as thunder.
Much of the energy we use at home comes from eletricity.Most of the Earth's energy-wind,waves,heat and light-comes from the sun.Itswarmth causes wind and draws water into the air,forming clouds.Its light allows us to see during daytime.The sun itself is powered by nuclear energy.
There are some things about energy that are difficult to understand.The fact that it comstantly changes from ome form to another makes energy rather like a disguised artist.When you think you know whyat energy is,suddenly it has changed into a totally different form.But one thing is certain:energy never disappears and,epually,it never appears from nowhere.People used to think that energy and matter were two completely different things.We now know that energy and matter are interchangeable.Tiny amounts of matter convert into unbelievably huge amounts of nuclear energy.The sun produces nuclear energy from hydrogen gas and,day by day,its mass gets less,as matter is converted to energy. |
