I didn't quite finish the analogy... "Imagine the wheel of a car being an electron, which is perfectly balanced and rotates perfectly. Now add a lead weight (a quantum of heat), and the wheel now is wobbling all around since it is 'out of balance'. That in turn causes the entire car (atom) to shimmy. The glue holding the lead weight can't stand the stress and the lead weight is ejected."
That quantum of heat then 'hits' or 'gets absorbed into' some other subatomic element, perhaps of the same atom, or a neighboring atom, and causes that one to be temporarily 'out of balance' and causes that atom to vibrate for a few attoseconds or so, but it too gets ejected. In what direction is it ejected? That too is more or less random for bulk matter. Thus, it makes perfect sense why QM is probability-based, and is so accurate when it comes to explaining things at the atomic scale. Now imagine billions of heat quanta constantly and randomly being shuffled from atom to atom... that's what's going on in bulk matter. -Mark
