Uncertainty Was NEVER the Observer Effect

You cannot know a particle's position and its motion at the same time, because the act of measuring one disturbs the other — looking changes it. That is how almost everyone was taught the uncertainty principle, and it is the wrong way round. The uncertainty is already there, before anyone looks. In January 2012 the headlines announced that Heisenberg had finally been proven wrong. But what those headlines were calling uncertainty and what uncertainty actually is were never the same thing. The famous "measuring disturbs it" story is Heisenberg's own first guess from 1927 — a burst of light knocking the particle it is trying to see — and Bohr talked him out of it within months. The real principle is a fact about the wave itself: sharpen a wave down to one place and its motion has to fan out; pin its motion to one value and its place has to smear — and that trade-off is baked into the shape of the wave with no observer, no detector, and no light in the room at all. Measurement really can disturb things. That is just a separate, real story the headlines confused this one with. An animated physics explainer that separates the two most-confused ideas in quantum mechanics and shows you the one that was there all along. #Physics #QuantumPhysics #UncertaintyPrinciple #AnimatedPhysics