Now, when it comes to studying work, there are basically three things you should have heard of and two things you need to assume. The first thing to assume is that in this life you get nothing for free. In other words, if you punch me in the face, you will have used up some carbohydrate from your morning’s oatmeal. The second thing to assume is that the world will come to an end, at which point there’ll be no work left to be done. Thirdly, you should be aware of the fact that there is a third law, but you shouldn’t devote time to asking me about it, mainly because I can’t really explain it. Now, it is important to remember that the key two laws are merely assumptions and not infallible notions. Consequently, thermodynamics is quite a theistic matter requiring faith, although in truth, that could be said about most things in life(, like swimming with white sharks).
Now to be honest, there’s no real disagreement about the first law at all. If you split a ten, you get two fives… that’s basically all it’s saying. However, from the second law onward, all consensus goes out the window. You see, the general gist of the second law is that if you do something, you’ll never be able to undo it without doing something else. Let me first of all explain the element of this statement where there is no confusion; by means of three examples:
- Peeling an orange
- Clapping your hands
- Lighting a match
Once you’ve done any of these things, it’ll take some job to get back to where you started. You just can’t unstrike a match, it’s un-un-doable, although you could just video tape it and then play it backwards (or notice that your Dad did that, talk about his idea in your blog and then shamelessly plug it: http://www.fun-engineering.net/unstrike-a-match.html).
Here comes the confusing bit though. People will sometimes say that when when you let a cup of coffee cool, you could easily undo that by heating it back to room temperature. The truth is that they are right. However, in order to undo the cooling of the coffee you have to heat it up, and to heat it up you have to do something else (like burn fuel or use electricity), and to undo that thing that you did to undo the cooling of the coffee you have to do something… anyway, I could go on… but the crux of the matter is that once you do something, you can’t undo it without doing something else. Now, here’s the climax of the argument: If you can’t undo what you did without doing something else, then eventually there will be nothing left to do (because you’ll have done it to undo something else). This, my friends, leads to the conclusion that the earth will indeed end, although this rather verbose derivation doesn’t really give an idea for the timeline in which that would happen!
Now, assuming that these two laws are true (which by the way could not ever be proven, but are the foundation for any engineering analyses involving energy), we can pose an interesting question to be answered in the next blog – If we must do something to undo something, how can we measure how much we have to do to undo what we did?
That’s where all the arguments began…