Dynamics said
Tell me, how does it go through it?I can't accept physically impossible things. Science is just the art of proving yourself wrong, so I'll stick with beliefs that don't go against basic physical laws. For example, an atom can't be in two places at once.
It just tunnels right through. The analogy is this: Imagine a ball rolling over a hill. Classically, if it doesn't have enough energy, it'll roll back down. Classically, if an atom didn't have enough energy to penetrate a barrier, it would bounce back or be absorbed. However, there's a small probability that it'll actually tunnel through even without the energy required to break through. This is because of quantum uncertainty and the principle that matter has properties of both waves and particles. Uncertainty states than it is impossible to know both the momentum and position of a particle exactly at a given moment. There is a limit to our preciseness when involving both.
Doing the maths shows us that the probability that the particle is on the other side of a barrier at the needed moment is not zero. Hence, there is a small chance that the particle will appear on the other side of the barrier, with a wave frequency proportional to the probability that it would happen (different with circumstances, of course, but always nonzero within 1-3 nanometers). That is how quantum tunnelling, an actual proven thing that happens and we use, works.