Where does energy come from and where does it go?

Question

My physics book, in the section on conservation of energy, says that energy cannot be created or destroyed. The book doesn't provide much of an example except for dropping a pen to the floor. The pen and the floor have a slight rise in temperature. If energy cannot be created or destroyed, it sounds to me like it has no beginning or end. So, if you didn't create the energy when you picked up and dropped the pen, where did it come from? After you drop the pen to the floor, there is a slight rise in the temperature of them both. Is this heat the energy? If so, where does it go when the heat is gone? I'm confused. This is my first class on physics.

Answer 1

The law of conservation of energy should more accurately be called conservation of mass and energy. Otherwise, you would need to say that the thermonuclear fusion reaction in the sun is destroying matter and creating energy.

Less intuitive is the idea that, although energy is conserved, it gradually becomes less 'useful' or of a lower grade. This is the idea of entropy and the second law of thermodynamics.

Cosmology tries to figure out the early history of the universe. Even if a Big Bang view is correct, it still doesn't say where it all came from. For that, all we have is Genesis 1:1, "In the beginning, God created the heavens and the earth."

Answer 2

The total energy of a system cannot be either created nor destroyed. It can only change. The picking up of the pen in your example... the pen had no potential energy while resting on the floor. You input kinetic energy and work energy into the system by moving the pen to a higher level relative to the floor. Now it has the same total energy, through conversions, while you are holding it. That energy is changed again into kinetic energy when you let it go. When it strikes the floor, the impact, slight though it may be, causes energy from the impact to travel through the particles in the pen and the floor causing an increase in their motion--again very slight. The increase in motion of particles in and object is an increase in temperature. There are a very very many ways to analyze any system. Things like work energy, potential energy, kinetic energy, temperature energy, even like previously answered energy on a quantum mechanical scale, etc. However, if you take the time and do the math, the total energy in the system before the action or reaction will be equal to the total energy after the action or reaction.
On the cosmic scale, this implies that the universe, when dealt with as a "whole system" got it's set amount of energy at the instant of the Big Bang. To follow through this course of logic, then it will end with the same amount of energy. Again, though now it's time to analyze and get very detailed measurements of all types of energy and matter inside the universe. This is the problem with current physics/cosmology. Things like dark matter, dark energy and keeping in mind that energy and matter are covariant make the measurement difficult. But, so far, there hasn't been any system when fully, completely and accurately scrutinized, that has violated the law of conservation of energy--all energy can always be accounted for, even if it's deemed it got converted into some currently theoretical state.

Answer 3

This is a slightly outdated concept, actually energy spontaneously appears and disappears on a quantum scale constantly in all points of space.

However on the scale you are talking about, all of these examples are simply transferences or conversion of energy. The sun heats the earth, the plants use that energy to gro, we eat the plants, we raise the pen and drop it. That may seem silly, but that's exactly what is happening. You don't "create" the energy when picking up the pen, you convert the energy you have consumed into muscle movement in your arm.

When the energy is slightly raised on the floor, it disperses into the air and other matter around it in the form of infrared radiation. This energy may go off into space or slightly increase the random motion of the trillions and trillions of atoms in the air until the random motions are indistinguishable from it's normal motion or is offset by some other tiny tiny energy loss or gain.

Answer 4

Energy was created in the beginning of OUR Universe...through the accumulation of infiniestimal particles traveling at infinitesimal speeds through space gethered together forming a greater energy area called an "epod". The Universe before it formed into what it is today which is a matter type Universe. Was created from the accumulation of infinitesimal energies which over time formed into a gigantic "epodes". An 'epodus" is the formation of what the Universe was formed from. Or what it was before it changed form. Called the big bang. The Universe was first a gigantic and growing epodus epod.
It continued to enlarge or grow until it reached a critical density that was equal to the dark matter substante that surrounded it. As a result - the epodus - absorbing enough of the dark matter - caused the epodus energy epod to chain react and caused an explosion we call the big bang.
After the big bang - the new Universe formed from the energy epodus epod. Formed through the chain reaction forming the explosion cahnged in composition and formed the earlier epodus energy or CosmicStar (egg) to transform in composition through the absorbtion of the existing dark matter that surrounded forming a planetary matter. This planetary matter are the planets, stars and galaxy we see today. All formed over an infinte period of time.
Planetary matter is the composition of dark matter substante space mixed with infinitesimal unstable energy I call " The Epodus " Universe.

If you read your physics textbook. You will read that dark matter substante is a substante that is inside all particle quantum and matter. Dark matter is an 'unknown' substante by science which entered the growth of energy (which came from the earlier existence of blackholes, and what I call other universe's already formed through the same process) when the CosmicStar or early Universe before the big bang reached critical density. critical density meaning the same density level as the dark matter that surrounded the EPODUS energy epod before its critical pre-natal birth stage.
Energy can also be created by a mechanism which creates a spark...

Answer 5

your physics book is right in saying that energy can neither be created or destroyed. In fact, energy is all around us. The food we eat has its own energy and our body transforms it to energy we can use so we can perform in our daily life. We excrete the waste and then it is absorbed by the earth. Here we would say that it is just waste but its not. It has taken another form. If left alone and covered for a period of time, it starts releasing gas that is another form of energy. This energy can be used to do all sorts of things. If not, then the earth absorbs it and turns it into fertilizer that the trees can use as nutrients to get their energy. Once it is in the trees, the animals eat the trees and the whole cycle is started over. If you ask how iron and plastic have energy, then just try to remember where these things come from.

Answer 6

to understand the energy to got to belive that the energy exist in everything in the world.

even the ball on the floor it have an energy (internal energy, intropy, entropy an so on)....

answer this question - how we got energize? from what source of our energy? if we think using our brain our head will becoming hot and hotter.

Outside air need equilibrium, it will take that heat/energy

dear Jeniffer if your can really understand this energy (thermodynamic) or soul or spirit transfomation or what ever they call, your can be magician, wizard of whatever if they wanna call you.

by the way ... happy belated birthday

Answer 7

it's true energy cannot be created, but it can be transferred/changed from one type of energy to another. for example the pen dropping gains kinetic energy (motion) and when it hits the ground, the kinetic energy is changed to heat energy due to friction. see?

Answer 8

The heat just spreads out. It gets 'conducted' away to the air and to the ground underneath the floor. It still exists, it's just spread over a wider area.

Ronin, I don't think someone who took their first Physics class today needs to concern themself with quantum mechanics yet.

Answer 9

e=mc^2.Matter and energy are equivalent.All matter is basically points of matter interacting.