Hi, I wanted to explain quantum tunnelling to people with no scientific background - I've come up with the following analogy, but I'm only a physics undergrad and I'm not sure if it's a good enough analogy. I can do the maths behind tunnelling but it's just the concept I'm trying to get across. I don't want to have to try to explain potential wells or the not-at-all-like-a-billiard-ball nature of tiny particles like electrons. The analogy I've come up with is this: Imagine you're throwing a tennis ball at a thick window. The tennis ball doesn't have enough kinetic energy to break the glass, so it bounces off. But if you do it enough times, if you close your eyes and throw the ball at the window, when you open them there's a chance that the ball will be on the other side of the glass. The only thing is I'm not sure if the glass should be intact or broken. As I understand it, it's not that the ball (or electron, say) borrows enough energy from the universe to break through the barrier, just that there's a finite chance of it being found on the other side when you look, so I was intending to say that the window won't be broken, but I wanted to check that that was accurate. Obviously any classical analogy for a quantum effect won't be completely accurate, but like I said I'm just trying to get the concept across. I appreciate any advice, just don't make it too technical!