Wave-Particle Duality and the Photoelectric Effect

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  • Опубліковано 31 січ 2025

КОМЕНТАРІ • 411

  • @ProfessorDaveExplains
    @ProfessorDaveExplains  6 років тому +508

    Guys! When I said that the smallest fundamental unit of energy is the Planck energy, that's totally wrong. That is a completely different parameter that is actually a macroscopic amount of energy. I confused it with the Planck time and Planck distance, so that label is being used incorrectly. Sorry!

    • @Adityasingh-pl9mc
      @Adityasingh-pl9mc 5 років тому +8

      A wave has a frequency... How can particles (photons) have frequency.

    • @Elegyforthend
      @Elegyforthend 5 років тому +4

      @@Adityasingh-pl9mc I think it's because at that time light is regarded as a wave and not a particle. not sure tho.

    • @Trypanosoma_
      @Trypanosoma_ 5 років тому +2

      @@Adityasingh-pl9mc photons emit a vertically-oscillating electric field that are described by the corresponding wave function of the photon

    • @active-ed
      @active-ed 5 років тому +2

      @@Adityasingh-pl9mc particle is a packet of wave..... that is why particle can have frequency

    • @active-ed
      @active-ed 5 років тому +2

      @@Adityasingh-pl9mc particle is a packet of wave that is why particle can have frequency

  • @mariamhashemi3950
    @mariamhashemi3950 9 років тому +310

    This saved my life! thank you. Especially, your saying "confused? you should be".......SIGH OF RELIEF!!!!!!!

    • @knowledgesource2
      @knowledgesource2 4 роки тому +1

      Hello sir , it's mean you are so creative man which get knowledge and zeal from anywhere and any sight ..keep it up
      Love from Pakistan 🌹🌹🌹

  • @malpacukierek4989
    @malpacukierek4989 7 років тому +520

    You make Khan Academy seem like a wast of the attention span; not bagging on them but you are literally the most efficient and effective teacher I've seen on the internet; especially when we consider this is chemistry. Don't stop dude! Explain everything forever yo.

    • @ProfessorDaveExplains
      @ProfessorDaveExplains  7 років тому +163

      that's the plan! please tell your friends to subscribe :)

    • @TheHamza1999
      @TheHamza1999 7 років тому +54

      I second you! Khan Academy is so much blabbering and time wasting, the videos seem so unplanned. While this guy is just amazing; concise, to-the-point knowledge.

    • @majidamaqbool5084
      @majidamaqbool5084 6 років тому +19

      Naah...Khan academy is a good source for boredom and time wasting

    • @yourfavouritescepticx8969
      @yourfavouritescepticx8969 5 років тому +3

      Professor Dave Explains this is the definition of a real G kids 😂

    • @jtcole146
      @jtcole146 4 роки тому +8

      @@LeatherCladVegan that moment when my chem teacher,(got second place for best science teacher in my state) shows this video in class to explains this topic...

  • @maaslander40
    @maaslander40 6 років тому +148

    I just signed up to be your sponsor on Patreon. I love your videos. I work as a science teacher at a small school and use your videos as a source of inspiration to make new lesson plans. Your comprehensions are also used in my lessons for my students. Keep doing what you do and I hope you will get enough funds to fulfill your passion. Love from Berlin.

  • @Kamoj85
    @Kamoj85 4 роки тому +23

    Thank you for this channel. it's very refreshing to have these chemistry topics explained easier than just reading a very wordy textbook that doesn't exactly explain the topic in terms to someone still learning the subject.

  • @zapperz2000
    @zapperz2000 4 роки тому +5

    Hi Prof. Dave. Thanks for your videos. I've linked a couple of them in my astronomy class that I taught last Spring.
    With regards to the PE effect, the notion that no electrons will be emitted for photons with energy lower than the work function, no matter how intense the light is, is only true for single-photon photoemission phenomenon. Since we now have intense laser sources, we can detect multiphoton photoemission. This is where photons with energy lower than the work function can cause an electron in a band (conduction band usually) to be raised to an intermediate state. But before it can decay back to a lower state, another photon comes by and excite it to another higher state. If this final state is a vacuum state, then it has the chance to escape.
    Multiphoton photoemission technique has been used in the study of materials, and also is a common phenomenon in particle accelerator photoinjectors. None of these means that Einstein's original model is wrong. It is just that we now know that the standard photoelectric effect is specific to the single-photon photoemission.
    Cheers!

  • @poorvalele9761
    @poorvalele9761 6 років тому +45

    heyy I am from India and I was browsing through so many videos and it was so much of textbook language and the concept wasn't really explained properly.I just discovered your channel and your videos are really amazing.They help to understand the concept quickly.Keep making more amazing videos. -Love from India

    • @icybear49
      @icybear49 4 роки тому +2

      This is in Chapter 2 of 11th grade Chemistry.

    • @shynishibu4082
      @shynishibu4082 3 роки тому +1

      Helped a lot for 11th grader like mee🙏🏻🙏🏻🙏🏻🙏🏻...❤️❤️❤️from India

    • @aryanaryan99899
      @aryanaryan99899 Рік тому +1

      ​@@icybear49cbsc

  • @NoName-ew6wz
    @NoName-ew6wz 8 років тому +111

    You teach a lot better than my teacher!!!!!

  • @majidamaqbool5084
    @majidamaqbool5084 6 років тому +5

    And then it happened as I am now loving science.
    It was a journey from boredom to awesomeness and lastly to curiosity about everything

  • @conormcgregor875
    @conormcgregor875 7 років тому +24

    your teaching can even make an 8 year old boy understand this high level science! this is what the world wants

  • @prixynealojado6998
    @prixynealojado6998 2 роки тому +1

    THANK YOU for this aaackk I'm a visual learner and I've been having a headache just watching other lengthy lecture videos explaining everything by word and description when all I needed is a clear visual illustration of how this works and this short video did it for me

  • @mshdbbdrbbdbd72
    @mshdbbdrbbdbd72 5 років тому

    Time saving, 3 min, only one mid roll ad at the end of the vid,teachs actually better than my teacher
    OUTSTANDING

  • @nipunisaumyaepage3522
    @nipunisaumyaepage3522 4 роки тому +4

    I am watching your videos for these two days for my quantum chemistry assignment..it is very easy to understand basic theory ..thank you very much..keep it up

  • @NeymarJR-du9rb
    @NeymarJR-du9rb 6 років тому +63

    He does a lot about the science stuffs
    Professor Dave explains!

    • @pedrosso0
      @pedrosso0 3 роки тому +5

      hm, I always thought it was "he knows a lot" but hey I might be wrong

    • @bakerstreet221c
      @bakerstreet221c Рік тому

      @@pedrosso0 yeah i also thought the same

    • @Nawab_A_S
      @Nawab_A_S Місяць тому

      @@bakerstreet221c same

  • @sehmio
    @sehmio 8 років тому +38

    Hi Professor Dave, I've probably said this a million times but thank you for these videos. They make me feel super nerdy because I get excited to learn about science!c

  • @sharmaravikant1287
    @sharmaravikant1287 6 років тому +2

    Sir , u seriously explaining physic in very simpler way,i deeply feel satisfy after clearing concepts explain by u.

  • @matthewspence7476
    @matthewspence7476 4 роки тому +1

    You’re a saint, doing this for no other reason than to teach people

  • @-mwolf
    @-mwolf Рік тому

    hands down most concise, clearest explanations out there

  • @missmoxie3065
    @missmoxie3065 5 років тому +18

    Ahhhhhhmazing, best channel ever. I'm acing chemistry because of you! You know so much!

  • @nani-m7s10m14
    @nani-m7s10m14 Рік тому +1

    "confused? you should be!" ... "Thanks to Einstein and others ..." XD
    Thanks for this, very helpful

  • @wouldbfarmer2227
    @wouldbfarmer2227 2 місяці тому

    Khan and Dave, and Jason, and Crash, and Bozeman and OCT are all helpful. I would never just want one teacher, or one source for any subject matter.

  • @iloveanyfood
    @iloveanyfood Рік тому +1

    Quantum mechanics unveiled a mind-bending reality: particles like photons and electrons blur the lines between waves and particles, showcasing a dual nature known as wave-particle duality. In experiments, these entities exhibit wave-like behaviors-interference, diffraction-similar to undulating waves, yet they also display discrete, localized impacts akin to particles. Attempts to confine them to a single definition falter; they exist in a state of quantum uncertainty, oscillating between wave-like and particle-like attributes based on experimental setups or observation methods. This profound concept revolutionized physics, dismantling classical notions and propelling us into a universe governed by probabilities rather than certainties.

    • @lepidoptera9337
      @lepidoptera9337 10 місяців тому

      There are no particles in nature. There are only people who can't remember the eight word sentence "A photon is a small amount of energy." that they were taught in high school science class.

    • @stupidteous
      @stupidteous 9 місяців тому

      ​@@lepidoptera9337what ?

    • @lepidoptera9337
      @lepidoptera9337 9 місяців тому

      @@stupidteous We are teaching the basics of quantum mechanics in high school. Have been for almost 50 years. :-)

  • @johntucker2566
    @johntucker2566 7 років тому +5

    Nice video man, you explain things really clearly, keep them coming :)

  • @miethadar5679
    @miethadar5679 Рік тому +1

    i only understand what is quantized when i see Professor Dave, Thank you Dave

  • @Saylor3561
    @Saylor3561 2 роки тому

    12 videos and it’s already more than I learned in all of high school chem.

  • @ltreaction4840
    @ltreaction4840 4 роки тому +2

    Thanks! You really help me in my study. My lessons become more easy because of you!

  • @imagiro1
    @imagiro1 Місяць тому

    3:05 : QM doesn't have to be confusing. It just gets confusing by the simplification stating that light *is* two things at once. Understand light as *having properties* of both a wave and a particle, and the confusion goes away.
    It's like a platypus: A platypus is not both a duck and a beaver. It just has properties of a duck (a beak) and of a beaver (a fur), but is its own thing: a platypus.
    Once I understood this, I started to understand quantum mechanics.

  • @mary_melody
    @mary_melody 9 років тому +11

    Thank you for this video! It was very helpful.

  • @zeinabebron4849
    @zeinabebron4849 Рік тому

    Thank you so much for helping me in grasping so many concepts! It's only a matter of fine-tuning your channel.

  • @herpyderpy2869
    @herpyderpy2869 Рік тому

    I'm in 11th Grade and I've been doing a bit of a refresher before school starts and this is is doing a lot of help. Thanks!

  • @shielabelleza6491
    @shielabelleza6491 3 роки тому +1

    I do love to watch your videos, it is full (complete) of info and easy to understand.

  • @ruvstof
    @ruvstof 6 років тому +3

    A very helpful work. Even people living here in Brazil can learn some physics.

  • @nirmitiautkar16
    @nirmitiautkar16 8 років тому +3

    And that video is
    the example of precision! really helpful...Thanks prof dave😊

  • @AndersonSouza0001
    @AndersonSouza0001 8 років тому +5

    Cool video. Clear and concise.

  • @tirthjoshi2773
    @tirthjoshi2773 4 роки тому

    You explain the easiest way anyone in the world can understand thank you so much.................... because of you our study become easy

  • @Will-jz9eb
    @Will-jz9eb 3 роки тому +2

    Good video. My knowledge has expanded greatly thanks to your efforts.

  • @Zephyr6083
    @Zephyr6083 7 років тому +1

    I have to say it again, your videos are so clear and so well explained. Don't stop! I recommend to all my friends now! By the way, will you be doing any videos on amino acid synthesis (gabriel, strecker)?

    • @ProfessorDaveExplains
      @ProfessorDaveExplains  7 років тому

      thanks kindly! right now i'm focusing on biology and math so no more organic chemistry in the works, but maybe one day!

  • @user-lb8qx8yl8k
    @user-lb8qx8yl8k Рік тому

    Dave one small objection if I may, but it might be a bit misleading to say that light "is a wave and particle AT THE SAME TIME."
    One of my QM texts (I can find out which one if you'd like) devoted a paragraph or so to explain that a quantum entity may exhibit both wave properties and particle properties, but never will it exhibit both wave and particle properties simultaneously. I asked gpt-4 to explain the concept of wave-particle duality and here's the relevant part:
    "The wave and particle aspects of quantum entities are complementary, meaning they cannot be observed simultaneously; observing one necessitates that the other is not being observed."
    I trust this is true because, like I said, one of my texts made this very point.
    The double slit experiment is a good example. Electrons exhibit wave properties when not being observed and particle properties when being observed. That just blows me away!!
    Even in spite of this and the thing about planck energy you noted here in the comment section, this is a very clear explanation of the photoelectric effect and the works of Planck and Einstein.

    • @lepidoptera9337
      @lepidoptera9337 10 місяців тому

      Yes, that was complete bullshit. ;-)

  • @Drderp-hd5bb
    @Drderp-hd5bb 6 років тому +1

    Awesome videos dude, really helping, plz keep making!!

  • @mariaangelaabalos8273
    @mariaangelaabalos8273 2 роки тому

    Oh my I got goosebumps upon learning about thiss. Thanks professor daveee!

  • @farhanlabibahan
    @farhanlabibahan 2 роки тому +1

    i am from bangladesh and enjoy youe videos a lot

  • @rifathossain6140
    @rifathossain6140 7 років тому +7

    dope intro dude i like it

  • @fabiomariaantoniali3096
    @fabiomariaantoniali3096 2 роки тому

    Hi Dave, the video is very effective! Actually Einstein used the term "energy quanta" in its 1905 paper, whereas the term "photon" was introduced in 1926 by G.N.Lewis.

  • @nqnqnq
    @nqnqnq 3 роки тому +1

    really good video! short yet concise.

  • @dhruvgamingyt3289
    @dhruvgamingyt3289 4 роки тому +1

    Thanks professor dave. I have no doubts.

  • @kristenyose740
    @kristenyose740 8 років тому +4

    Such a helpful video-- thank you so much!!

  • @RR42636
    @RR42636 7 років тому +1

    This is really, really good stuff man. Thanks!

  • @forhadahmed4643
    @forhadahmed4643 Рік тому

    best teacher on youtube....

  • @joelthomasjaison7748
    @joelthomasjaison7748 7 років тому +1

    Thank you professor Dave ...................
    You explained Grate...
    Continue with this

  • @sweetdemon5372
    @sweetdemon5372 4 роки тому +2

    Hello professor Dave
    I am watching ur videos since 2 months
    And I love ur videos
    Can u please do a QNA

  • @shreyashreemazumdar9295
    @shreyashreemazumdar9295 Рік тому +2

    Literally felt like Ranbir Kapoor explaining omg doppelganger

  • @isadora13correa
    @isadora13correa 7 років тому +2

    Thank you, your explanations are amazing!

  • @narimanomar2098
    @narimanomar2098 4 роки тому

    Oh my god! I have never been so happy you literally saved my life once again. Thank you so much!

  • @rajeswarikalyanasundaram6041
    @rajeswarikalyanasundaram6041 4 роки тому +8

    Professor dave what's the relation between stopping potential frequency and wavelength?

  • @chadley
    @chadley 7 років тому +1

    Here I am wishing my Chemistry professor is just as good as you

  • @aashrithasaraswathibatla9283
    @aashrithasaraswathibatla9283 4 роки тому +1

    I have an online exam today this is very useful to tq soo much profresser dave can u do more videos on spectrum

  • @nadalpushnof
    @nadalpushnof 3 місяці тому

    Hey Dave! At 01:52 you said that quantum theory went on to show that everything is quantized. This statement is incorrect! Gravity isn’t quantized (at least not yet- because string theory is still just a theory).

  • @funkydrummerplatypus
    @funkydrummerplatypus 9 років тому +2

    Really great video. Short, accurate, and to the point. Thanks so much Dave!

  • @sophie8869
    @sophie8869 4 роки тому +1

    you are the reason im going to pass my chemistry final

  • @adityathakur6424
    @adityathakur6424 7 років тому +6

    please explain me what is the proprties of wave and particle

  • @CesarTheWelfareCaptain
    @CesarTheWelfareCaptain 3 роки тому

    i finally understood what quantized mean, thanks Dave.

  • @themariola69
    @themariola69 6 років тому +1

    I love your videos!! please make more!!! I am using them for mcat studying! They are simply amazing and to the point!

  • @totoush1678
    @totoush1678 7 років тому +4

    YOU ARE A LEGEND!

  • @capyper2353
    @capyper2353 4 роки тому

    This course is amazing

  • @hossamzebian2164
    @hossamzebian2164 11 місяців тому +1

    if a certian surface metal plate is irraidiated with light an electron is ejected which can be detected when it interacts with a positively charged wire ot plate sensor

    • @hossamzebian2164
      @hossamzebian2164 11 місяців тому

      the ability of the light to eject an electron depends only on its frequency and not its intensity so if the beam was below certain frquency even if very intense beam with alot of light could not eject an electron

    • @hossamzebian2164
      @hossamzebian2164 11 місяців тому

      Albert einistain solved the problem by extending the concept of max planck

    • @hossamzebian2164
      @hossamzebian2164 11 місяців тому

      Energy is quantized and all energies are multiples of the smallest unit of energy (quant energy)

  • @rudymelo880
    @rudymelo880 3 роки тому

    "Confused? You should be." That's how I always feel when I learn wave-particle duality

  • @gretchenevans8132
    @gretchenevans8132 3 роки тому +1

    At timestamp 2:54, you say that the v in the equation is the frequency of the photon--why is it marked as a v instead of the f that was used earlier? I have been struggling with understanding the whole velocity vs. frequency thing.

    • @ProfessorDaveExplains
      @ProfessorDaveExplains  3 роки тому +1

      So it actually should be the greek letter nu, which looks very much like a v. It can be a little confusing, and I should have just used the greek letter here.

  • @johnweldon1259
    @johnweldon1259 2 роки тому

    Thank you! Understand this better now

  • @MedSou
    @MedSou 6 років тому +1

    Thank you,nice explanation👍👍👍👍

  • @zy9662
    @zy9662 8 років тому

    Great video, thanks. At 2:15 you say quantum theory went to show that space and time is quantized, but I think this has not been shown yet, that would be a proved theory of quantum spacetime, meaning a proved theory of quantum gravity (spacetime is gravity according to general relativity), which I think we still lack.

    • @ProfessorDaveExplains
      @ProfessorDaveExplains  8 років тому

      nope, not necessary! the planck distance and the planck time are both well established and ubiquitous in modern physics. though you are correct in identifying the main challenge in producing a grand unified theory, as quantum mechanics has not yet been merged with general relativity.

    • @zy9662
      @zy9662 8 років тому

      Thanks for replying, but the words you use: "established and ubiquitous" can be confused for the layman as physical reality, and the Planck length (or time) has no proven physical significance, meaning there is no experiment that proves its existance, this is my point

    • @ProfessorDaveExplains
      @ProfessorDaveExplains  8 років тому

      i did some quick googling and it seems that you are correct that these concepts are not as physically significant as i assumed, though in the wikipedia of each there were some concrete applications of each (beyond quantum gravity). at any rate i definitely subscribe to the idea that space and time are made of quanta, so perhaps i will just have to learn more and see how physics develops!

    • @zy9662
      @zy9662 8 років тому +1

      chuvzzz can you elaborate with an example why Quanta is the result of imposing boundary conditions?

  • @kayladelgadillo3854
    @kayladelgadillo3854 5 років тому

    Thank you for helping me with physics.

  • @wcomsa
    @wcomsa 8 місяців тому

    very clear explanation thank you

  • @legendrybeast3398
    @legendrybeast3398 6 років тому

    Very interesting video cleared all doubts

  • @Pierrot110194
    @Pierrot110194 8 років тому +1

    Hi Dave! I loved your videos on organic chemistry, they've helped me a lot during my first year. I have to say though, in this particular video (I don't know whether this effect prevails through the entire series) the presentation seems obviously read to the viewers, rather then explained, if that makes sense. It's not a biggie, just throws you off a bit, maybe try to remember a little more and not read as much? I just try to give some constructive advice. Anyways, as I said you're doing great work nevertheless! Thanks :)

  • @atomx8723
    @atomx8723 3 роки тому

    He knows a lot about the science stuff!professor dave!

  • @andreasjodahl7354
    @andreasjodahl7354 3 роки тому

    Love your videos! Keep it up king

  • @tlovahaval7301
    @tlovahaval7301 Рік тому

    You’re such a life saver 💘

  • @matifadzaaa
    @matifadzaaa 2 роки тому

    I UNDERSTAND HAHAHA THANK YOU PROFESSOR DAVE!!! im so hyped!

  • @jaidenzheng6969
    @jaidenzheng6969 6 років тому +1

    Better than my teacher, a true teacher.

  • @anuugrah
    @anuugrah 8 років тому +1

    sir , could you post a video on waves and their super positions

  • @osta9016
    @osta9016 4 роки тому

    Thanks for the video. It really helped.

  • @haseebali576
    @haseebali576 3 роки тому

    Sir you are great love the way you teach stay happy respected Sir

  • @sanjaygajbhiye2809
    @sanjaygajbhiye2809 Рік тому

    sir you are rockstar love you from nagpur, india

  • @Rik....
    @Rik.... 3 роки тому

    Great intro Professor Dave :)

  • @nimitapurohit3986
    @nimitapurohit3986 4 роки тому

    Awesome teaching

  • @David_Hardy
    @David_Hardy 7 років тому

    Nice explanation

  • @paulperez3013
    @paulperez3013 3 роки тому

    If sound is also a wave, why doesn't sound have particles along with its waves? What happens to the particle along the wave spectrum, or does waves reach a certain energy that it attracts particles, traps or knocks particles out of somewhere? Are the missing particles the fundamental building blocks of waves or things that pop in an out of existence all the time?
    Why doesn't sound have particles?

    • @ProfessorDaveExplains
      @ProfessorDaveExplains  3 роки тому +1

      Because it's a reverberation of the particles in the air.

    • @paulperez3013
      @paulperez3013 3 роки тому

      Thank you. I relearn something again. Had a science mental block

  • @jdstudios1912
    @jdstudios1912 7 років тому

    Absolutely brilliant!

  • @sanjuansteve
    @sanjuansteve 3 роки тому

    Since we know we’re in a sea of undetectable dark matter but don’t know exactly where it’s distributed and since everything in the universe from electrons to solar systems is in orbit with something else, why isn’t the first assumption of how or why a photon acts like a particle but also as a “wave packet” for every physics student to think every photon might be in orbit with a dark matter particle pulling it into a polarizable axial or helical apparent wave as they travel?

  • @TomHendricksMusea
    @TomHendricksMusea 3 роки тому

    Ask an astronomer "How are photons created or destroyed", talks about quantum jumps.
    Q. The only interactions a photon has are to be created or destroyed.
    My idea is that the photon pops up as an electron positron pair that power the quantum leap or releases a photon.
    That means that the leaping electron interacts with the electron positron pair. One electron and positron annihilate which powers the left over electron to jump.
    That means that in space time photons are always electron positron pairs.

  • @SinemihleNtshangase
    @SinemihleNtshangase Рік тому

    “Confused? You should be” 🤣✋🏾

  • @CHALI_GRACE
    @CHALI_GRACE 2 роки тому

    May God bless you❤
    You're videos save alot of people
    Thank you soo much

  • @trieuhuyvan5020
    @trieuhuyvan5020 3 роки тому

    it's a bit early to find out about you, I hope it's the same. Thank you so much

  • @flexible3351
    @flexible3351 2 роки тому

    it was really helpful thanks a lot

  • @josephcallahan1664
    @josephcallahan1664 3 роки тому

    Excellent. Thanks.

  • @wendishaver9520
    @wendishaver9520 2 роки тому +4

    Why can't college courses be taught like this?

  • @markdeadman1884
    @markdeadman1884 6 місяців тому

    I am confused, but you made it much easier to understand! Hallelujah! Finally, I found a video that explains this. Thank you for disarming Flat Earthers in other videos.

  • @yashpatel4683
    @yashpatel4683 4 роки тому +1

    But number of electrons ejected is proportional to the intensity / brightness of the light . ( I just read it in my journal ) .

  • @JaykeSapalaran-iq3qs
    @JaykeSapalaran-iq3qs Рік тому

    Great video information very informative ❤ thank you for sharing your knowledge and experience 🇵🇭🫡

  • @tiffanyproa863
    @tiffanyproa863 4 роки тому +1

    "the speed limit of the universe" Love you dave LOL