Professor Dave Explains
This is a classic experiment that is frequently referred to when describing quantum phenomena, so we definitely have to go over it a little bit. What happens when you pass a beam of light through a screen with two slits? What about when you send electrons through there? It’s crazy stuff! Check it out.
Subscribe: http://bit.ly/ProfDaveSubscribe
ProfessorDaveExplains@gmail.com
http://patreon.com/ProfessorDaveExplains
http://professordaveexplains.com
http://facebook.com/ProfessorDaveExpl…
http://twitter.com/DaveExplains
Classical Physics Tutorials: http://bit.ly/ProfDavePhysics1
Modern Physics Tutorials: http://bit.ly/ProfDavePhysics2
Mathematics Tutorials: http://bit.ly/ProfDaveMaths
General Chemistry Tutorials: http://bit.ly/ProfDaveGenChem
Organic Chemistry Tutorials: http://bit.ly/ProfDaveOrgChem
Biochemistry Tutorials: http://bit.ly/ProfDaveBiochem
Biology Tutorials: http://bit.ly/ProfDaveBio
American History Tutorials: http://bit.ly/ProfDaveAmericanHistory
Source
Excellent explanation and visuals
great video 🙂
Who else is here from Aotabuta?
Do you humans also realise that in the enormity of what you term the "Big Bang" the unmeasurable energy was only given to single particles. The Electron throughout your universe is an individual particle dissipating the colossal energy of the "Big Bang" appearing to Human Perception to be everywhere at once, causing you humans to experience "Spooky Action at a Distance" and the wave like interference patterns of your universe's Elec-trons
A Particle Exhibits a wavelike property in a transmissable ether having a probability of existing in a particular point in Space time as a function of what you humans experience as Time
"Wave-like behavior" is not the same thing as declaring an electron a wave. If it was the same you would hear physicists (let's stick with the good ones) drop the "-like behavior" part off that phrase. Are you thinking of DeBroglie "matter waves"? That theory does not claim something as drastic as "particles are waves" but rather is an attempt to fit experiment to theory. All experiment tells us is this: after looking at the screen we deduce an interference pattern that indicates, based on our knowledge of wave behavior, that if this was a wave-slit system that wave would have a wavelength which produces the pattern. Instead, and since what we see on the screen is the only thing observed (i.e. no one has ever observed an electron looking like a wave – only a quantized entity absorbed in this case and not spread out in the way you're implying), we are forced to describe this behavior as "wave-like" which simply means "we can't really explain what it is other than that we detect it in quantized lumps only". I think this theory has created a lot of confusion that is now rampantly circulating on YouTube and elsewhere (some Ted Talks are mistaken on this point as well).
For double slit in particular, it's incorrect to say that the single electron approaching the barrier "is a wave", but let's assume that it is for a moment. This implies that part of the wave enters one slit while another part enters the other while the rest is spread out within some volume that doesn't include the slits. But this contradicts DeBroglie's relation lamba = h/mv for the lamba observed at the screen (after a great many electrons strike it). What is m if part is in between one slit, part is in another, and almost all the rest of it is elsewhere? m in your case would be just a small fraction of the total mass of the electron in which case we'd observe a much different pattern at the screen. Instead, what's observed is the pattern expected for the total mass. This is the mystery of this experiment and the reason for why it's so famous – it cannot be understood by simply claiming that the electron is a wave so DeBroglie et al. called the behavior "wave-like" since there's really no other way to describe it.
The best we can say is that there is a wave-function which solves for the energy state of the system. That wave-function can be used to calculate the likelihood of detecting the electron in a certain volume during a specific time interval, but it does not indicate that the electron itself would ever look anything like a wave.
love your stuff Dave, but here you went straight from discussing wave like behavior of matter (depending on experiment) to claiming "all particles are also waves". whoops! unfortunately there is no QM reasoning that results in this assertion, and it's perhaps one of the most confusing elements of the entire field. In the case of the double-slit experiment for instance, QM formalism presents the tools allowing us to solve for the double-slit system. In doing so we end up with a wave-like solutions for the system as a whole. those solutions are mathematical. they are combinations of wave "functions" like sine waves. the same can be said if you wanted to describe a point in space: it can be described as a combination of an infinite number of wave "functions". because of this one may say it has wave properties (depending on how you look at it) but that does not make it a wave.
Wait! You didn’t explain why the interference pattern disappears when an observer is present (when individual electrons are shot through the double slit)?
What is the current explanation??
Can you please explain how one can isolate and shoot just one electron at a time?
I thought electrons are mostly “fields” and Not an “item” that can be isolated individually.
All Subscribe this channel
cant help but think of the wave beam from Metroid Prime. is that weird?
Great explanation! Glad I came across this channel, even though we disagree about the shape of the Earth. ?
I err.. shall pretend I understood whatever was being said for the last 4mins.
Prof Dave, so many Thiests want their God/s to fill in the gaps. I find their ignorance mind numbing. What are your thoughts. Just been watching Trace Harris on the Atheist Experience about the double split and some Thiests saying this proves the existence of God.
Hey Dave, i can imagine both waves and particles. How does a wave-particle look like ?
The phenomenon of diffraction as well as the phenomenon of double-slit experiment are caused by the interaction of a particle near the slit with the walls of the substance in which the slit had been cut. A detailed submicroscopic theory of the phenomena are described in a book entitled Structure of Space and the Submicroscopic Deterministic Concept of Physics (2017).
Professor Dave, if we perform the double slit experiment with photons in stead of particles with a rest mass like electrons, does the diffraction pattern of single photon passes through the pair of slits look the same whether you compute the diffraction pattern stripe-distance according to waves of the photon frequency or according to the quantum wave dispersion?
It is said that light waves propagate due time varying electric field( which produces time varying magnetic field ). From sun to earth, is it that electric field exit for light to travel and reach earth. If yes, how ? (Because both sun and earth are nurtral bodies and there are no charged bodies either in the surrounding ) and is this field the same as coulomb electric field?
Dude you need a haircut.
I thought humans mostly emit light in infrared, so that would mean we have very large (compared to particles) wavelengths (not negligible)…can someone explain that part to me??
The most important points, the observation and the rays where left out. Which are held that quants stay in solid static state.
Like Einsteins Question: "Is the Moon not there when we don't look at it ?"
Sure it is there since in case of Rays which are every where present in the universe and which force the quants into their static state bc they are measured now.
"…no matter how much you diet…" thanks for calling me fat!
3:41 we can clearly see Hitler on the left and Jordan Peterson on the right, that's what I got from this video
great
In my book there's a 3 page topic on young double slit experiment so…. see ya later
There's so much in Quantum Physics that we could really use here on Earth.!There are a few actual physicists who touch on really wonderful applications that could make our world and our individual reality far better. Because from what I've gathered from these physicists, as well as reading some of the writings of the Founders of Quantum Physics, and from other sources, and thought experiments of my own, there is no matter at the subatomic level, only energy, and that energy responds to our expectations, our beliefs, and our truths. To me, this non material nature of everything in the universe, logically makes our universe spiritual or mental in nature, and so it's thoughts and beliefs that need to be upgraded/uplifted to create a more abundant and satisfying "reality" for us as individuals as well as for the world in general. A Quantum Leap would really be nice right about now! This doesn't contradict anyone's belief in God, but actually really strengthens it, and if you read Genesis I, you would think a Quantum Physicist wrote it… saying that we are "created in God's own image and likeness" (that would be Spiritually), and that we have "dominion" over the things of the Earth… (matter???) And lots more.
Thank you Dave for giving us a chance to discuss this subject.
you look iranian
WONKA VISION ?
Finally understood the YDSE
Thanx sir
I subscribed your channel
"so this will be pretty tough no matter how much you diet" ????
But if the slits are smaller than the object passing through it wouldn’t light always come out as a wave? Just as the illustration?
Why is the wave only horizontal? If the slits were the same size vertically and horizontally would the wave pattern be in both directions? Or if round, in a circle?
Does sound play a part in this? I imagine the electron, or particle, would make some sound no matter how minute, and sound travels as a wave.
Can the individual particles really be treated as individual particles? With the unimaginable fast speed of travel of the particles and the short distance the particles travel isn’t it safe to say that the particle is present in the complete path in which it travels, while it exist? Acting more like a solid object extending from the particle “producer” to the back wall detector (doesn’t as a particle travels it fades from one spot in time (since light is the cosmic speed limit, doesn’t light sorta determine time) and reappears in the next spot only to fade and repeat?)?
Wouldn’t the way particles travel through space and time, and understanding such, play a huge role in evaluating this experiment? And are the fraction of a fraction of a fraction……of a second in which these particles are traveling really understood?
Just curious, in all the videos I’ve seen there is always an example of a body of water with a wave traveling towards 2 slits and the wave pattern is formed on the back wall(detector). I’ve never seen the “horizontal wave only” addressed when we are dealing with traveling particles. Sure a wave in water will make the horizontally extending wave pattern but why is light also extending horizontally, and not in EVERY direction? Would the wave pattern extend vertically if the slits were rotated 180 degrees?
Probably dumb arse questions, this experiment is just so hard to believe. Easy to see what is happening, just hard to believe.
I'm curious I would like to see an experiment where they add more measuring devices and instead of just having one in the front have one behind the two discs and one in each slit and have them where you can turn them all off and on at different intervals and try them all out and see what happens ? For example if they had the one in front and one behind the disc turned off but the two in each slit turned on I wonder if sometimes it would split into two and that way they could prove it that's one atom split into two or more ??? That would be cool I'd love to see a video on that and see if they could do that which I believe fully that they can.