Could someone please explain to me the law of conservation of energy? I know the law itself, but could someone explain what it means, and what is meant by "conserving energy".

Question

anonymous · Answer

people tend to get confused when they hear 'conserved'.. cause they tend to thing 'save'.. 

conserved basically means that the final and initial quantity remains the same.. so for example

if initially there were 4 apples in a room, and you go out and come back if now there are still 4 apples.. you can say the no of apples were "CONSERVED"... otherwise (if someone ate one.. or added another one) we say the no. of apples are NOT conserved! 

so can you now build intuition about energy?

anonymous · Answer

Energy is a characteristic of a physical situation (as a collection of interacting masses, or a  container of water stirred by and electric motor powered by a battery) defined mathematically by certain physical properties of that system like velocity of components , position of components,  electric current and voltage, burning fuel or chemical makeup.  No matter what happens in this situation, no matter how it changes, no matter what occurs the total energy of that situation does not change. It may change its form ie motion, heat, relative position of components etc. but the sum total of the energy content of each form will be the same as in the beginning. 

One must assure that they define the situation so as to account for all the energy. Thus if you have a situation in which the energy at the end of the observed change is different from the beginning then you must find out where it went if the energy is less than the beginning or where it came from if the energy increased and account for the difference.  It is one of the most, if not the most, important conservation laws in Physics.

anonymous · Answer

WHAT?!? :O.. that is the most absurd thing i have ever heard :O...  @rajathsbhat

anonymous · Answer

Thanks for the explanation, i, like most people was thinking that conserved meant saved, and i guess in this case (in a sense ) kinda does. but thank you so much for explaining it to me. it makes much more sense now.

anonymous · Answer

no problems :)