Quantum superposition is a phenomenon in which a tiny particle can be in two states at the same time — but only if it is not being directly observed.

A Planck? Planck’s constant like the physics number for something complicated? Nah, that’s not keyboard related. But maybe it is. Let’s talk about Planck keyboards, a special keyboard that ...

That’s pretty much all you need for instruments to determine Planck’s constant to a decent degree of precision, the way that [poblocki1982]’s did. There’s a little more to it, of course ...