I sort of get how they get formed and how it works but why do they not bump into other particles? and do the spins have to do with this?
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2$\begingroup$ I think it's not that they don't bump, but rather that they only bump elastically at low energies, and, thus, don't loose energy. Someone that works with superconductivity will correct me if I'm saying anything wrong. $\endgroup$– Hydro GuyCommented Feb 9, 2016 at 14:49
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Spin indeed plays a role in this. Cooper pairs are bosonic in nature, below the critical temperature they condense into the same state to form a superfluid phase responsible for superconductivity. This is why they do not "bump into eachother", they are all in the same state.
Moreover, the condensation of Cooper pairs opens a gap in the excitation spectrum at low energies. This means that you need a finite amount of energy to break up a pair if a Cooper pair were to collide with something else inside the material. The energy gap $\Delta$ is of same order of magnitude as the critical temperature $T_c$, in a way you can think of the superconducting transition as thermal fluctuations breaking up Cooper pairs when you reach $T_c$.
Also keep in mind that electrons forming pairs can actually be very far away from eachother, say a few hundreds of nanometers. Thus many pairs can occupy the same space, they form a very rigid superfluid phase that moves in "one block" and does not get affected by defects or other particles.
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$\begingroup$ What role do the spins play here? $\endgroup$– user106621Commented Feb 10, 2016 at 15:54
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$\begingroup$ Electrons are spin-$\frac{1}{2}$ fermions. When they pair up they thus form a composite boson of integer spin: Cooper pairs can condense into a superfluid because they have integer spin. $\endgroup$– DimitriCommented Feb 10, 2016 at 16:22