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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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.
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.
So true!
Ilyn Payne.....
That oxygen tank is size "W". For Wumbo.
W...wide? Wow that's big? Whoa now?
Wholly too much, With Excess, Without end. lol.
astrong0 Whopper
Patrick saying this somehow springs to mind
The size of my wiener
no explanation?
Well, science happens, which causes pretty colours. For a more detailed explanation please visit.......the Internet.
... THEE IINTEERNEEEETTTTTT!!!!!!!
Mexi Chemia There are no manganese ions in this demonstration, though. The colour results from redox reactions between the indigo carmine and glucose.
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
@@jhyland87 They explained it...
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
what happens if we overshake it
I'm quite surprised she's not wearing gloves, considering the fact that she's making a pretty strong base with the sodium hydroxide.
Can you PLEASE show how it can go back to green again?
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.
The stream of yellow liquid turning red as it hits the flask is a really neat visual effect :)
That is great !!
As always Thanks from Italy.
Can you get it back to green?
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.
Theoretically? yes
In practice? you'll have to put some effort into this
this one accually gave me a stroke of genuine childish awe. i feel silly and privileged at the same time.
Love that demonstration, fun to watch.
Brady and the crew deliver again! This was pretty good :D.
Great video! Forwarded this to my students x
I love this video! It looks like fun! I'm sure the children love that reaction! Your videos are awesome!
Thanks
Awesome! I love the these videos as well as Sixty Symbols! Keep it up!
@KlaxonCow:
Well put, VERY well put!
Amazing, thanks for the great upload!
My favourite Periodic video!!!
Good videos. Keep them up. Do you take requests?
i love how the red-green transition is instantaneous.
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!
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
that was ridiculous! very cool reaction!
Can someone explain why chemical reactions are able to change colors that we percieve?
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
Poke Playah electrons play a large role in determining the chemical and physical properties of a substance.
***** Thanks man
+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
Caleb Price TL:DR
Cool, very nice experiment.
That was awesome!
I did enjoy it, ty sir.
pretty cool experiment!
Good video. Would it work with sucrose instead of glucose? That is more readily available in the US.
amazing video
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.
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
this is a really nice effect
That's quite interesting! I would appreciate if you could you chemically describe exactly the reaction. Thank you for these videos!
Very good video :) thank you
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!).
That's so awesome!
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.
The cylinder is SIZE W for WOAH, that's a lot of O2.
Actually, it's size W for WUMBO.
This just topped my list on the best chemical reaction!
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)
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.
What a fun experiment!
@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.
Indeed. I did that one for my coursework; very nice.
Fascinating!
awesome experiment.
That. Is. AWESOME!!!
Could we also use an oxidation agent like H2O2 or NaOCl to reverse this reaction?
Brilliant!
i watched it again. its awesome.
its also cool how the yellow-red change happens
sry stupid ctrl+c/ctrl+v mistake you are 100% right, and it was nice of you to explain the reaction
that was fantastic!
this was super!
superb!
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?
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
love this
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
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
That's one big ass conical flask. Cool reaction
That's pretty awesome.
@savtoz No, it's a indicator for O2.
It's works too with Potassium Permanganate (KMnO4) instead of Indigo Carmine
Sir Ryu so glucose with NaOH with potassium permanganate will work?
amazing!
when i saw that i thought about some interesting reaction where is producing singlet oxygen, it looks awesome because it glows!
holy hell, that impressed me. wow.
Witchcraft
+Mexi Chemia
Woooosh!
Pretty cool!
@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.
is this a redox reaction like the blue bottle reaction?
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.
Is it some sort of reversible redox reaction?
this is my favorite at home reaction
Those are some fancy stoplights. Where I live, we just used colored LEDs.
@raydredX Well some might say that Chemistry is just applied physics. Either way they are closely related.
what concentration of glucose n sodium hydroxide are we suppose to take in the water?
Very awesome :)
THAT IS SOO!!!! COOL!!!
What are the reactions taking place?
May I have the amounts please. Thanks!
can u buy the dye indigo carmine for demos at a store or online? and the sodium hydroxide?
I think Sodium Hydroxide is a common cleaning product,so you should be able to find it quickly
Since these are somewhat harmless chemicals you can buy them online easily.
very nice
This still amazes me.
amazing! :)
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.
@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)
awesome!
so cool!
Isn't indigo carmine a pH indicator?
@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.
Is this like an equilibrium type thing?
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.
what are the materials i need to do this?
So could you take the oxygenated solution and apply a vacuum to turn it yellow, right?
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.