Classical Mechanics vs. Quantum Mechanics

[CalvinTNguyen2D]

Could anybody help explain the differences between Classical Mechanics and Quantum Mechanics? I was a little bit confused by how the lecture example of water pouring out of a bucket could be modeled by both types of mechanics. Thanks!

[Katherine Wu 1H]

In classical mechanics the events tend to be continuous, which is to say they move in smooth, orderly and predictable patterns. In quantum mechanics, the events are unpredictable, which is to say "jumps" occur that involve seemingly random transitions between states.

[Cavalli_1H]

with the water example, I think he meant that, at a certain point in shrinking the stream of water, you'd get to a point where the smallest amount (a single H20 molecule) could be able to pass through, and when this happens there'd be 'jumps' of water pouring out, and not a constant stream. the classical mechanics of this situation would be observing the solid stream as the water pours out when the stream is still large, and the quantum mechanics comes in when the stream shrinks to the point where the smallest amount of water would be pouring out. idk if this helped but this is how I interpreted the bucket example

[Nuoya Jiang]

Hi, so in a classical mechanics, we see things and explain the reasons behind them in a macro scale, and as a result, our measurement is continuous. In a quantum mechanics, or a situation for micro things, everything is so small that we can only use discrete numbers to describe a transition. Try to imagine you climb up hill with a flat and escalated lane, or with stairs.

[nickianel_4b]

I agree with what everyone else said, basically quantum mechanics explains behavior at such a small level that everything is in discrete amounts (like photons and atoms, or the water molecules from his water bucket example). I think that's why he also said you can't have 1.2 or 2.33 of something in quantum mechanics--because whole numbers are already as small as it gets. Hope that helps :)