Traffic Lights - Periodic Table of Videos

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  • čas přidán 21. 02. 2010
  • The traffic light reaction sees a solution change colour from green to red to amber.
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Komentáře • 593

  • @periodicvideos
    @periodicvideos  Před 4 lety +9

    These videos are made by Brady Haran - check out his "Unmade Podcast" here: bit.ly/UnmadePlaylist

  • @spagamoto
    @spagamoto Před 11 lety +3

    There is nothing stupid about enjoying learning something new. Sadly as we get older, we tend to lose this enjoyment. I for one applaud the University of Nottingham for doing an excellent job in keeping the fascination alive.

  • @hausser0815
    @hausser0815 Před 8 lety +35

    Neil always reminds of that guy from GoT Season 1/2 without a tongue. same hairstyle, same facial expression, and they both have equal dialogue time on screen.

  • @astrong0
    @astrong0 Před 7 lety +123

    That oxygen tank is size "W". For Wumbo.

  • @MartynDerg
    @MartynDerg Před 8 lety +118

    no explanation?

    • @Kizron_Kizronson
      @Kizron_Kizronson Před 7 lety +59

      Well, science happens, which causes pretty colours. For a more detailed explanation please visit.......the Internet.

    • @FWAKWAKKA
      @FWAKWAKKA Před 7 lety +6

      ... THEE IINTEERNEEEETTTTTT!!!!!!!

    • @christianvn1
      @christianvn1 Před 6 lety +10

      Mexi Chemia There are no manganese ions in this demonstration, though. The colour results from redox reactions between the indigo carmine and glucose.

    • @jhyland87
      @jhyland87 Před 5 lety +14

      I see a lot of "the internet" comments in reply to this... This is a science channel... This is typically where the internet would lead you, so i agree, there should be an explanation

    • @jakeledd
      @jakeledd Před 4 lety

      @@jhyland87 They explained it...

  • @mouseclick92
    @mouseclick92 Před 14 lety +3

    Showed this to my science teacher a year ago, I think. And now he's using it all the time when we have chemistry.
    Keep up the good work... A lot of students apreciate your help :D

  • @LizardKing1086
    @LizardKing1086 Před 8 lety +10

    I'm quite surprised she's not wearing gloves, considering the fact that she's making a pretty strong base with the sodium hydroxide.

  • @parakhmody1413
    @parakhmody1413 Před 8 lety +18

    Can you PLEASE show how it can go back to green again?

  • @DarksideoftheSteve
    @DarksideoftheSteve Před 8 lety +13

    How about doing this with the high-speed camera? It would be interesting to watch the colour changes in slow motion - the Iodine Clock video was fascinating in slow motion.

  • @mush01
    @mush01 Před 14 lety +2

    The stream of yellow liquid turning red as it hits the flask is a really neat visual effect :)

  • @leonardopesaresi7170
    @leonardopesaresi7170 Před 9 lety +3

    That is great !!
    As always Thanks from Italy.

  • @SkittleDash
    @SkittleDash Před 10 lety +31

    Can you get it back to green?

    • @Scy
      @Scy Před 9 lety +3

      I think the answer is no. It was green because of the temperature difference, I think. You can't revert that and cool down some molecules and some not.

    • @1998wiwi
      @1998wiwi Před 6 lety +3

      Theoretically? yes
      In practice? you'll have to put some effort into this

  • @HansenSWE
    @HansenSWE Před 12 lety +1

    this one accually gave me a stroke of genuine childish awe. i feel silly and privileged at the same time.

  • @P00P0STER0US
    @P00P0STER0US Před 14 lety +1

    Love that demonstration, fun to watch.

  • @drokles
    @drokles Před 14 lety

    Brady and the crew deliver again! This was pretty good :D.

  • @gdca20
    @gdca20 Před 14 lety +1

    Great video! Forwarded this to my students x

  • @greglitke4919
    @greglitke4919 Před 11 lety

    I love this video! It looks like fun! I'm sure the children love that reaction! Your videos are awesome!
    Thanks

  • @leviathanfafner
    @leviathanfafner Před 14 lety

    Awesome! I love the these videos as well as Sixty Symbols! Keep it up!

  • @vbpeepee
    @vbpeepee Před 14 lety

    @KlaxonCow:
    Well put, VERY well put!

  • @gnfr211
    @gnfr211 Před 12 lety

    Amazing, thanks for the great upload!

  • @tubolgat
    @tubolgat Před 11 lety

    My favourite Periodic video!!!

  • @samn100
    @samn100 Před 14 lety

    Good videos. Keep them up. Do you take requests?

  • @doctorwholover2112
    @doctorwholover2112 Před 11 lety

    i love how the red-green transition is instantaneous.

  • @bdnugget
    @bdnugget Před 14 lety +1

    Wow that's really cool! I did it with potasium permanganate intead of indigocarmine, but that ins't reversible that way. This is way more awesome!

  • @Mikej1592
    @Mikej1592 Před 9 lety

    that is so cool, I really like the pouring of yellow and when it hits the surface it is totally red from the O2 so cool

  • @JumpStop1
    @JumpStop1 Před 14 lety +1

    that was ridiculous! very cool reaction!

  • @Naijiri.
    @Naijiri. Před 9 lety +35

    Can someone explain why chemical reactions are able to change colors that we percieve?

    • @michaelangeloparkinson5055
      @michaelangeloparkinson5055 Před 9 lety +23

      Poke Playah I would assume it's probably because since the chemicals mixed in with each other, it absorbed different amounts of light, changing the visible color to us.That's just an assumption though, don't take my word for it

    • @Blox117
      @Blox117 Před 9 lety +10

      Poke Playah electrons play a large role in determining the chemical and physical properties of a substance.

    • @Naijiri.
      @Naijiri. Před 9 lety +1

      ***** Thanks man

    • @calebprice7896
      @calebprice7896 Před 8 lety +40

      +Poke Playah In this reaction, glucose (an aldehyde) is in an alkaline solution of Sodium Hydroxide (NaOH) and is slowly oxidized by dioxygen (O2) to form gluconic acid:CH2OH-CHOH-CHOH-CHOH-CHOH-CHO + 1/2 O2 -----------------> CH2OH-CHOH-CHOH-CHOH-CHOH-COOH
      Gluconic acid is converted to sodium gluconate in the presence of sodium hydroxide. Indigo carmine speeds up this reaction by acting as an oxygen transfer agent. By oxidizing glucose, indigo carmines oxidation state is itself reduced, and becomes green. It is then reduced further and becomes red. Again it can be reduced further and will turn yellow. If there is a sufficient available oxygen (from air), indigo carmine is re-oxidized and the yellow color of solution can be restored to red. So basically what is happening is the indigo carmine is going under oxidation state changes (So called "redox reaction" for Reduction-Oxidation Reaction). But as chris handy said, it is the different molecules that are being formed and their shape that causes light to be absorbed and emitted at different frequencies (by extension, colors). Just thought it would be handy as to why the reaction actually can change several colors!
      Source(s): I'm currently attempting to get my organic chemistry Bach. degree

    • @kerberossi
      @kerberossi Před 8 lety +1

      Caleb Price TL:DR

  • @n310ea
    @n310ea Před 14 lety +1

    Cool, very nice experiment.

  • @841067596
    @841067596 Před 13 lety

    That was awesome!

  • @jammydodger128
    @jammydodger128 Před 11 lety

    I did enjoy it, ty sir.

  • @somuchsoul
    @somuchsoul Před 14 lety +1

    pretty cool experiment!

  • @davagain
    @davagain Před 12 lety

    Good video. Would it work with sucrose instead of glucose? That is more readily available in the US.

  • @daonpa
    @daonpa Před 14 lety +1

    amazing video

  • @superdau
    @superdau Před 14 lety +1

    Yes. It's quite easy to get (at least here in Austria) even by mail order. But it's not as harmless as it looks. The solution with water is caustic. Just have to know what you are doing.

  • @chuckles731
    @chuckles731 Před 12 lety +1

    there's a really awesome chemical reaction where you put some chemicals in a beaker on a stirring and heating machine and it changes colour back and forth on it's own

  • @vanidar21
    @vanidar21 Před 14 lety

    this is a really nice effect

  • @fuggles
    @fuggles Před 14 lety +2

    That's quite interesting! I would appreciate if you could you chemically describe exactly the reaction. Thank you for these videos!

  • @JakkaF
    @JakkaF Před 14 lety +1

    Very good video :) thank you

  • @superdau
    @superdau Před 14 lety

    Indigo Carmine is used as (blue) food coloring and glucose is (grape) sugar. NaOH is also used to prepare lye rolls (quite common here in Austria). I wouldn't drink it though. I don't know the concentration, but a NaOH solution is alkaline (this is the reason for the color change; indigo carmine is also an pH indicator) and can be caustic.
    But you could dunk some dough in it, bake it and have some nice blue sweet lye roll ;-) . Just do it in a kitchen and not in a lab (no foods in a lab!).

  • @ctfxcfangurl
    @ctfxcfangurl Před 12 lety

    That's so awesome!

  • @genicide81
    @genicide81 Před 14 lety

    We preform this demonstration at my school, we place the solution in a bottle with a good amount of air head space. Swirling the solution will turn it red, shaking it vigorously will turn the solution green. If anyone is interested in demonstration chemistry I would suggest checking out books by Bassam Z. Shakhashri. He has many experiments like this one with in-depth explanations of the processes involved.

  • @alexflohr1453
    @alexflohr1453 Před 8 lety +24

    The cylinder is SIZE W for WOAH, that's a lot of O2.

    • @U014B
      @U014B Před 8 lety +4

      Actually, it's size W for WUMBO.

  • @Legolaaa
    @Legolaaa Před 14 lety +1

    This just topped my list on the best chemical reaction!

  • @Taconut7
    @Taconut7 Před 12 lety

    Is there a certain molarity you have to have the NaOH solution? Also does it matter how much sugar you use? (I plan on creating a design lab based off of this reaction)

  • @awesomescarlett5229
    @awesomescarlett5229 Před 11 lety +6

    When I first started forensic science I tried to explain this reaction to my chemistry teacher. She had no idea what I was on about and told me it must be universal indicator solution. -_-
    Well, now I know.

  • @ElveeKaye
    @ElveeKaye Před 14 lety +1

    What a fun experiment!

  • @insAneTunA
    @insAneTunA Před 14 lety

    @periodicvideos I like these videos a lot, but maybe it is a good idea to make some annotations about safety when it comes to certain materials and experiments. Untrained people might wanna copy the experiment at home without knowing the effects and reactions from the substance that is used with certain other materials.
    But keep the videos coming, I learned a lot, and now I have a better understanding of the elements.

  • @DevilMudger
    @DevilMudger Před 14 lety +1

    Indeed. I did that one for my coursework; very nice.

  • @detronyx
    @detronyx Před 10 lety

    Fascinating!

  • @AcanLord
    @AcanLord Před 14 lety

    awesome experiment.

  • @ndean1687
    @ndean1687 Před 2 lety

    That. Is. AWESOME!!!

  • @japjustjap3273
    @japjustjap3273 Před 4 lety +2

    Could we also use an oxidation agent like H2O2 or NaOCl to reverse this reaction?

  • @SciPhi161
    @SciPhi161 Před 12 lety

    Brilliant!

  • @HansenSWE
    @HansenSWE Před 12 lety

    i watched it again. its awesome.

  • @doctorwholover2112
    @doctorwholover2112 Před 11 lety

    its also cool how the yellow-red change happens

  • @user21XXL
    @user21XXL Před 14 lety

    sry stupid ctrl+c/ctrl+v mistake you are 100% right, and it was nice of you to explain the reaction

  • @MichaelZola
    @MichaelZola Před 11 lety

    that was fantastic!

  • @yorkandpomona
    @yorkandpomona Před 14 lety

    this was super!

  • @Anonyminded
    @Anonyminded Před 12 lety

    superb!

  • @x3na3
    @x3na3 Před 12 lety

    would this work with any base and indicator? or should it be solid NaOH [we haave liquid]; we dont have indigo die either. any substitute?

  • @trfccurt07
    @trfccurt07 Před 14 lety +1

    Anyone notice the green tint as soon as it hits the bottom of the container when she pours it, its only there briefly but try and pause it

  • @abelhoul
    @abelhoul Před 14 lety

    love this

  • @omermagen824
    @omermagen824 Před 8 lety +1

    Can you please make a new video since you have got a new high speed camera and i would like to see this reaction in slow motion? And it will also be very nice if you will explain the chemistry that is taking place. Thanks

  • @pfoth
    @pfoth Před 11 lety

    Sodium hydroxide catalyzes the glucose sugars ability to act as a reducing agent. Glucose reduces the original oxidized indigo carmine. Oxidized indigo carmine is a green colour and reduced indigo is amber orange. The red colour we see before it gets to amber is actually a transition step (like a half reduced indigo). bubbling oxygen into the mixture reverses this process re-oxidizing the indigo molecule making it red. As of why indigo is these colors at these steps, well, electronic transitions

  • @revorocks123
    @revorocks123 Před 14 lety

    That's one big ass conical flask. Cool reaction

  • @FrostPegasus
    @FrostPegasus Před 14 lety

    That's pretty awesome.

  • @bartomanboy
    @bartomanboy Před 14 lety

    @savtoz No, it's a indicator for O2.

  • @Ryuorly
    @Ryuorly Před 9 lety +3

    It's works too with Potassium Permanganate (KMnO4) instead of Indigo Carmine

    • @mistertheguy3073
      @mistertheguy3073 Před 7 lety

      Sir Ryu so glucose with NaOH with potassium permanganate will work?

  • @gurlz8
    @gurlz8 Před 14 lety

    amazing!

  • @maciejdelekta6167
    @maciejdelekta6167 Před 8 lety

    when i saw that i thought about some interesting reaction where is producing singlet oxygen, it looks awesome because it glows!

  • @310BPM
    @310BPM Před 14 lety

    holy hell, that impressed me. wow.

  • @AsheronsFall
    @AsheronsFall Před 8 lety +28

    Witchcraft

    • @DANGJOS
      @DANGJOS Před 5 lety

      +Mexi Chemia
      Woooosh!

  • @exaedeth107
    @exaedeth107 Před 8 lety

    Pretty cool!

  • @rogeryermaw
    @rogeryermaw Před 13 lety

    @aashish7kumar5 actually if watch the entire series you will hear him speak. i can't recall which video but i have heard him speak. it is quite rare.

  • @nicechem123
    @nicechem123 Před 12 lety

    is this a redox reaction like the blue bottle reaction?

  • @SaifZahir
    @SaifZahir Před 14 lety

    Glucose in the presence of sodium hydroxide acts as a reducing agent, and actively reduces the dye, indigo carmine. Thus, its most oxidized state, indigo carmine is blue. In its most reduced state, the dye is yellow. As oxygen (an oxidizing agent) is bubbled through or mixed into it, it gets oxidized again but is quickly reduced again because the Gluc-NaOH mixture is in excess.

  • @intermission101
    @intermission101 Před 14 lety +1

    Is it some sort of reversible redox reaction?

  • @miesrah12
    @miesrah12 Před 14 lety +1

    this is my favorite at home reaction

  • @ericl8743
    @ericl8743 Před 4 lety

    Those are some fancy stoplights. Where I live, we just used colored LEDs.

  • @ModernGameChangers
    @ModernGameChangers Před 12 lety

    @raydredX Well some might say that Chemistry is just applied physics. Either way they are closely related.

  • @unnatiperishetty2877
    @unnatiperishetty2877 Před 9 lety

    what concentration of glucose n sodium hydroxide are we suppose to take in the water?

  • @BoomRoomFive
    @BoomRoomFive Před 9 lety

    Very awesome :)

  • @daniel75o
    @daniel75o Před 14 lety

    THAT IS SOO!!!! COOL!!!

  • @borgdylan
    @borgdylan Před 2 lety

    What are the reactions taking place?

  • @sheisonewholoveslife
    @sheisonewholoveslife Před 7 lety +1

    May I have the amounts please. Thanks!

  • @OboeFiles
    @OboeFiles Před 8 lety

    can u buy the dye indigo carmine for demos at a store or online? and the sodium hydroxide?

    • @nicolashurtado1073
      @nicolashurtado1073 Před 7 lety

      I think Sodium Hydroxide is a common cleaning product,so you should be able to find it quickly

    • @christianhoffmann8252
      @christianhoffmann8252 Před 7 lety

      Since these are somewhat harmless chemicals you can buy them online easily.

  • @jubilantgnome
    @jubilantgnome Před 14 lety

    very nice

  • @Profolie
    @Profolie Před 9 lety

    This still amazes me.

  • @mandrakesMD
    @mandrakesMD Před 14 lety +1

    amazing! :)

  • @RMoribayashi
    @RMoribayashi Před 11 lety

    Sorry I misunderstood. It's all very confusing, especially at night around high pressure sodium vapor street lights. To red-green colorblind people like me street lights look green and green traffic lights look white. I've read that some countries have a reflective border around the entire signal, a really great idea.
    A co-worker of mine once brought her blue-yellow colorblind boyfriend to work. We had a bit of fun at her expense by having a mock argument over colors for about fifteen minutes.

  • @FerSFumero
    @FerSFumero Před 13 lety

    @puncheex acids will draw water, alkalis might as well, but the danger from alkalis is that saponification occurs, and the fat in the skin reacts with the base. An acid-base reaction occurs with the fatty acids, and they are separated from the glicerine molecule to for glicerine and a fatty acid salt (a.k.a. soap), that's why an NaOH solution feels slippery (even in diluted solutions)

  • @CarlosDuarte2007
    @CarlosDuarte2007 Před 9 lety

    awesome!

  • @vickylikesthis
    @vickylikesthis Před 11 lety

    so cool!

  • @savtoz
    @savtoz Před 14 lety +1

    Isn't indigo carmine a pH indicator?

  • @FmMan33
    @FmMan33 Před 14 lety

    @YellowMagi
    Of course not, and I'm all for telling people to work it out themselves before asking. My point is you can't call someone a moron just because they asked a question. We're always asking questions from childhood and it's the only way we truly learn.

  • @K2Tanner
    @K2Tanner Před 14 lety

    Is this like an equilibrium type thing?

  • @pickagreatname
    @pickagreatname Před 14 lety +1

    So I'm guessing that's a pH indicator and the glucose is reacting with the base to change the pH of the solution, then that reaction is reversed by oxygen somehow? I wish you guys would go into more detail about the reactions you're doing.

  • @sanchezbrian295
    @sanchezbrian295 Před 12 lety

    what are the materials i need to do this?

  • @aligatorsandwitch72
    @aligatorsandwitch72 Před 12 lety

    So could you take the oxygenated solution and apply a vacuum to turn it yellow, right?

  • @akkudakkupl
    @akkudakkupl Před 11 lety

    Well indigo carmine is a pH indicator. In high pH it turns to yelow colour. As the hydroxide mixes in the second solution the pH rises through time. It is also a redox indicator thats why it turns red again as it is oxidised by oxygen.