system
Given the following post, respond as if you're commenting on Reddit:
human
Does quantum indeterminacy affect macroscopic events?

Of course it affects some macroscopic events (such as the behavior apparatuses used in physics experiments), but in general does quantum indeterminacy filter up?

Suppose I were to drop a bagful of marbles. Would there be a non-trivial chance that they would have landed in noticeably different locations?
gpt
Nope. Quantum behavior doesn't 'filter up'. The heavier something gets, the less 'quantum' its behavior is. By the time you've gotten to things as heavy as entire molecules, they don't behave very quantum-mechanically. For instance, you use x-rays and determine the positions of atoms in a crystal to within fractions of an Ångström, which is basically an 'unnoticable' distance on the _chemical_ scale, (much less the macroscopic one).

Besides mass, the other thing that affects whether something acts quantum mechanically or not is the extent its able to interact with the environment, since that's what constitutes a 'measurement' quantum-mechanically speaking. If something is constantly being measured, it can't evolve into a quantum superposition state (aka the 'quantum zeno effect'). 

So we see quantum mechanical behavior when you're dealing with light objects, such as subatomic particles. And you can see those objects acting together in large-scale quantum behavior when you're dealing with a system that doesn't interact much with the environment. For instance, the electrons in a superconductor (which are typically cold, rigid substances). Or superfluid helium (which is obviously very very cold). The main reason why it's so difficult to build a quantum computer (which works off superpositions) is precisely this - it's difficult to scale it up and still keep it isolated enough to preserve the superpositions. 

If a bag of marbles at room temperature could act quantum-mechanically to any significant extent, we'd have discovered QM long before we did. But some quantum superpositions were in fact found before QM, although it wasn't known at the time. For instance, the bonds of the benzene molecule form two possible structures, which Kekulé described as 'oscillating' (in modern chem terminology 'resonance structures'). But they're actually a quantum superposition (or at least can be viewed as such - what qualifies as a superposition of states hinges on how you define your states)