Comments by "EebstertheGreat" (@EebstertheGreat) on "The Original Double Slit Experiment" video.

It also would have misled a lot of people. The effect of "observation" is usually accepted to be an effect of macroscopic interaction. That is, there is a continuous process that occurs between interactions of isolated particles and interactions of very large systems of many entangled particles. Anything we call an "observation" must somehow be observable to us as big fat humans, which means it must involve a huge number of interactions to produce a macroscopic effect. It is this process that actually causes the "collapse" that seems to happen. Note that very few physicists today subscribe to an "objective collapse" interpretation, in spite of the popularity of these interpretations in the very early days of quantum theory. Rather, a deterministic, continuous process that follows the mathematics of quantum decoherence is usually preferred. The multiple worlds interpretation is one such example. Specifically, there is no evidence that conscious observers play a special role in quantum mechanics. But when you tell people on the street about the "observer effect," that is exactly what they will assume you mean. That's how we get quantum woo like Deepak Chopra's books.
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@shaash8323 PBS Spacetime
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@Darian Johnston In the double slit experiment, the particles are isolated before the observation. For instance, light is allowed to pass through the slits either because it is in a vacuum or it is just in a substance with a low refractive index that doesn't interact with it much (like air). As a result, the wave function remains coherent after passing through the slits, so both parts can interfere with each other. But if you observe it first, you must interact directly with part of the wave function, and this rapidly leads to decoherence. Note that you can even have two particles interacting and still maintain a coherent quantum system as long as they are isolated from the environment. Decoherence happens as the result of a very large number of entanglements, when different parts of the same wave function can no longer interact with each other. We end up seeing just one, and the philosophical reason behind that is disputed.
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My favorite answer to the question about the double-slit experiment was at 3:59. "There's some kind of principle involved that the average person is not familiar with." This guy gets it, even if he doesn't "get it." It's not a trick question, but the answer is definitely too difficult to figure out if you don't already know it. It's not like the questions about the inertia of the stone globe on water. Racking your brain just won't help here, and you should just let Derek get on to the explanation he's going to give anyway.
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