A couple of weeks ago. I uploaded a video about the double slit experiment
The purpose of this video was to capture some of the excitement that comes with learning about a new physics idea for the first time
For this reason I chose to use the dr
Quantum double slit explainer video and got some of my friends to react to it
I chose this video because it was reasonably short and
Explained some of the aspects of the double slit experiment in a reasonably engaging and fun way
but that video isn't perfect and especially since the video of mine got more views than I really
Anticipated it to I feel like I want to clarify a few things
When I first saw that, dr. Quantum video, I was in high school and I didn't know anything about physics
Despite some of its flaws, which I'm going to discuss in this video
I found that it was one of the things that gave me enough interest in physics to actually go on and do a physics major
it was a source of intrigue and
Curiosity for me and I hoped that that is what it would also be for some of my audience members
I'll put some links in the description for you to pursue some of these ideas more
But let's talk about some of the flaws of the video the main problem with the dr
Quantum video as pointed out by many of you in the comments
comes when it starts to discuss using a detector to
determine which of two slits a particle goes through as it appeared to be going through both slits and interacting with itself to create an
Interference pattern when the detector is used the particle goes back to behaving
Classically it only goes through one slit and the interference pattern on the wall is lost
This is called a which way experiment in the dr. Quantum video
They use an eye to represent the detector and they say it is as if the particle knows it is being watched
but this is a bit misleading because in reality the detector is measuring the particle and this measurement is
interacting with the particle it is this interaction that causes the interference pattern to be lost a
Quantum particle moves as a wave of probabilities of being in any location. its exact location
Is unknown and if you were to measure its exact location
you would collapse the wave function this would also cause you to lose the
Interference pattern which was caused by the wave-like nature of the quantum particle
Here is a clip of Neil deGrasse Tyson talking to Joe Rogan about this idea. So I'm looking at you
The only reason why I can see you is
Because there's light reflecting off of your face your body
Into my eyes. I want to know where you are
So I turn on the lights and I say there you are. Alright now, let's make you tinier
Let's make you mini-me
Okay, like in the movie, all right
So now is a tiny version of you a mini-me version of Joe Rogan. Now your little I turn on the light you're still there
Okay. Okay, cuz if the lights are not on I can't see you. I don't know where you are. Right? It's that simple. Okay, okay
When you start becoming the size of molecules
Right on down to the size of an atom and I ask the question
where is Joe Rogan the atom and
I turn on the light
to see you there because I think you're there the light the photon comes in hits your atom and
Pops you into another location
Hmm the very act of trying to measure your position
prevents me from measuring your position and it has Jack shit to do with your consciousness or your mind or your eyes or
Anything it has to do with the fact that to know you're there some information has to come from you to me
like shining a light on you and the smaller you are the more susceptible you are to
the the energy of the light
Changing your position in space and to the point where that's actually it's a Heisenberg uncertainty principle
it's one of the basic foundations of all of quantum physics. methods to detect the particle could also include putting a
Polarizing filter over one of the slits or a thin layer of material which would change the way that the wave propagates
These methods affect the
coherence of the wave and would also lead to the loss of the interference pattern. when discussing the idea of trying to figure out which
Slit, the particle goes through people are often actually talking about a delayed choice experiment or the quantum eraser
In a delayed choice experiment a detector is placed after the slits and this seems to retroactively affect
How the particles were behaving when they went through the slits
PBS space-time has a really good video on this which I'll link down below
What's most important is that the interference pattern is lost when information
About which path the particle has taken becomes available to the external environment
It doesn't matter if this information ends up in the brain of a human
the brain of a frog is seen by a pot plant or just leaks out into stray air molecules a
Conscious observer is not a necessary part of the process
For a good argument on why a conscious observer is not required. Please read the article quantum mechanics needs
No consciousness. in this article
They talk about experiments where which way information about the path that a particle took is
Measured but not on a macroscopic device
So not available for a conscious observer to read
The information was stored in the state of a single atom and under these conditions
The interference pattern was still lost meaning that a conscious observer was not required to cause collapse of the wavefunction
I have seen claims that quantum mechanics is vital to understanding consciousness
But I think that having these two mysteries
Disentangled from each other is an important step in being able to understand both of them a bit better
This is my current understanding of the experiment based on the information that I've read about it if you think anything else needs further
Clarification please post a comment about there were some really thoughtful and helpful comments in the comment section of my last video
But there was also some hostility towards people with alternative viewpoints
I would rather they feel like they can say their misconceptions and
Have them corrected in sort of a kind manner rather than feeling like there is a lot of hostility towards them
there were also some comments that kind of surprised me from people saying things like oh
How could anyone not know about the double slit experiment?
I learned about this as a child and sort of insinuating that anyone who hadn't learnt about it was somehow below then
To that I say that, you know, if you don't have friends from a range of different
Education backgrounds and interests, then that's not something to be proud of I don't consider
someone knowing about the double slit experiment to be a
Criteria for them to become my friend or for me to talk to them
In fact, I really enjoy talking to people from you know, a whole variety of interest don't hate on people
Who are willing to learn new things just because they're not at your level
I think it can be somewhat easy to get trapped in a bubble
where all your friends are sort of at the same level as you they know the same things and have similar interests and
You can gain a warped perception of what general knowledge really is and what?
general people are concerned about and know about
I think though that possibly that should be something you want to go out of your way to try and correct to
Talk to more people who have different interests from you and to try and broaden your own knowledge and understanding. Thanks for watching this video
Thanks to everyone who did leave really insightful comments on my last one, and I'll see you next time
