Learn how atoms touch at a macroscopic and microscopic level.
Atoms touch all the time! But to understand why we first have to decide what we mean by the word "touch." Our normal conception of touching is grounded in the macroscopic world. I put a cup on the table – the cup is touching the table. You dip your toes in the water – you are touching the water, and so on. In all these cases, one solid boundary or surface (the bottom of the cup, the edge of your toe) touches another solid boundary or surface (the top of the table, the surface of the ocean). But our macroscopic conceptions break down at the microscopic level, which is where the confusion over "touching" comes in. Read More:Will Humans Ever Go Faster Than Light? Atoms and Boundaries If we could zoom into atomic scales, we would see a madhouse. Atoms and molecules are constantly flying around, bumping into each other, twisting, spinning and overall making a mess. But one thing quickly becomes apparent: Atoms do not have a strict boundary. There's the nucleus, a bundle of protons and neutrons in the center, surrounded by clouds of probability of where orbiting electrons might be located the next time we go looking for them. The theory of quantum mechanics tells us how to calculate those probabilities, and the range of those probabilities covers the entire universe. However, almost every single time we look at an atom, the electrons are safely…