Chemistry
Why the Born–Oppenheimer Approximation Separates Nuclear and Electronic Motion
Quick fact
The Born–Oppenheimer approximation is so powerful that nearly all quantum chemistry software relies on it. It states that because a proton is about 1836 times heavier than an electron, nuclei move so slowly that electrons 'instantly' adapt to any new nuclear position.
Why this is interesting
You've probably seen pictures of molecules in chemistry textbooks—balls connected by springs. But have you ever wondered how we can even calculate the behavior of electrons that zip around those balls? That's where the Born–Oppenheimer approximation comes in.