Quantum Tunneling

Today I want to explain "Quantum Tunneling".
Tunneling? Yes, tunneling. If you see this word, you may think a tunnel that is in a mountain or under sea: Eurotunnel. But it is not. This "Quantum Tunnel" doesn't exist really. There are only effect called "Quantum Tunneling".Anyway what is "Quantum Tunneling" and it happens?

You may hear this word before in something about personal computer, particular CPU. There is the  problem caused by this effect. And "Quantum Tunneling" is microscopic effect.You won't see this effect macroscopic, otherwise you are very, very, very lucky. I want to explain this effect using a wall and a electron. If electron want to go over the wall, you have to have more and more energy. But now, I want to you to remember that "Quantum"'s character. "Quantum" is wave! There are a wave on world and the wall. Quantum wave is not able to be seen by us, we can see where particle is after wave can't be seen. It is nature! We can do only agree! But relation between wave and where the particle is, using probability. Wave height relates to probability of where particle is. In somewhere if wave height is higher, probability that particle exist there is higher. And wave is waving now. If here wave height is more lower than one over the wall, you could see the particle in the other side of wall! This is "Quantum Tunneling".