[2] Fusion This one came out a little late, but oh well...

[Baniboy 3]

SOOOOO, After some time of the first part of this series, here comes the second. The reason I wrote this so late is that I went on a vacation for like 20 days, and the started the school. So I was busy and couldn't hang out at trap(also the fault of the stupid uptime Xisto seems to have nowadays, I couldn't access the site after 20:00).So, for all the newer members or the ones that last time missed(or just weren't interested in that topic), I suggest you read the first part now, and come back here later. Click here to read the first partYou didn't read the first part, did you? GO READ THREAD NUMBER ONE FIRST! AND I MEAN IT THIS TIME! :lol:So, the subject of this physics thread is about Nuclear reaction. There are two types of these: * Fusion, where multiple atoms fuse together and form a heavier atom. * Fission, where one heavy atom becomes unstable and divides into multiple lighter atomsFirst, we'll look at the most common one, fusion.This nuclear reaction occurs mostly in stars, such as in our solar system's star, the sun. I will now tell you the basic principles of fusion.Fusion isn't possible, if the particles don't have enough kinetic energy (speed, in short terms). Why? Well, as you probably learned in your physics and/or chemistry lessons, there is an electrostatic force between atomic particles. So if we for example have 2 atoms at a normal state, they don't fuse, because the protons have all positive electrostatic charge and they repel each other. There is another force involved in this as well, there's always nuclear force, which only kicks in if the nuclei are close enough to each other.In the last chapter, we learned that heat(in every day term)/thermal energy is motion. Temperature of an object is the amount of thermal energy it has as a whole(this is because the thermal energy rate can vary within an object, "hot spots").So, the hotter the particles are, the faster they move. If we get the temperature high enough, the kinetic energy can overcome the electrostatic force. After electrostatic force has been overcome, nuclear force kicks in. Nuclear force is much stronger than the electrostatic force, but doesn't work if the nuclei aren't close enough to each other.Unlike nuclear fission, nuclear fusion binds energy, it doesn't release it. There obviously are exceptions! Well, the story is kinda complicated, so I'll go through this quick.In fusion, you need enough energy to fuse them. But the reaction also releases energy. The amount of released energy is more than the amount of energy you need to apply for nuclei to fuse. This applies for all elements from Hydrogen (1) to Iron (13), actually iron is sharing the place with nickel too, but let's not bother to think about it now. After iron and nickel, fusing chemical elements will require more energy than the reaction will release, so these reactions aren't self-sustaining.Most of you probably remember that fusion means fusing Hydrogen into Helium, but this is obviously not the case, all heavier chemical elements are the product of fusion.Fusion also isn't only protons bumping into each other and bind, there are neutrons, positrons, radiation all the other cool stuff involved also.I've decided that I'll talk about fission in another topic since I feel it needs it's own thread.

Edited September 5, 2009 by Baniboy (see edit history)