I tried this with my Year u and 9 classes as a demo and the students are in awe. They love chemistry. I've done the dancing flames and blue bottle from your videos as well and I love seeing the wonder in their eyes.
After 9th grade's final exam, my students lost will to study. Then I started to find something inspiring them and I reminded "Traffic Light Solution(In our country, we call it like this :D)" that I made in our university's conference. I tried with no specific recipe and I failed and I searched this video. Your instruction REALLY works. Now I'm getting more chemical knowledge from RSC. Thanks for a bunch of COOOOL stuff! AND~ I have two Q. Q1: Is there some specific concentration to make turquoise? Q2: Is there some proper ratio between NaOH : Glucose?
+Terpsichore13th thanks for the feedback - check www.rsc.org/eic/2014/05/indigo-carmine-traffic-light-demonstration for further info. The trick to getting blue is working below pH 11.4 so you don't push that initial colour up into the green through the high pH. Use the 0.4M NaOH and add when adding the sodium hydroxide (changing from blue form) you need to stop adding just as it's about to turn green. You can tune the turquoise at which you stop to your own preference. If you added all the NaOH it would go to green (half blue/half yellow) but if you add a bit less then there is more blue than yellow so it looks turquoise. As for ratios .. well it depends what you want. The amount of NaOH will affect the colour of the dye from a pH perspective (see article) - the OH- ions are useful to us in assisting the formation of the aldehyde form of the sugar before being further oxidised. So playing with the ratios affects both the series of colours you get and the rate at which the whole thing proceeds (it's 1st order wrt both the glucose and the OH-. The ratio provided is a sweet spot for use with a class when you want it to do its thing 'on command' :)
Question: Will Chemiluminescence occur if one added some luminol to react with the hydroxide of the NaOH in the mixture with the diluted indigo carmine? In addition, Will one need a metal catalyst to activate the luminol?
0olong thanks for the comment .. to be honest I'm surprised you got it to last that long :) As you can see in the attached article in the description , the glucose is constantly being reacted through to the final product, sodium arabinonate. Along the way there are two intermediates of relevance to the reaction and the most important one is the enediolate anion which reduces the dye. Eventually as the glucose is used up, no more of this anion is around to do it's job so the flask will stop working.
Hitman Monkey haha it might be! Filming these videos alone often leaves me for long hours in the lab trying to sort out lighting, framing and focus and getting the reactions to work "just right" so sometimes my belly has to wait ;)
It turns out that trying to juggle speaking to two people, whilst ensuring you say everything you need to say to camera in one take, whilst worrying if you're going to be asked to leave by the cafe owner is more difficult than it looks. I felt awful when I watched the footage back!
I tried this with my Year u and 9 classes as a demo and the students are in awe. They love chemistry. I've done the dancing flames and blue bottle from your videos as well and I love seeing the wonder in their eyes.
This is a fantastic demonstration - Students from 5 - 19 years are enthralled
After 9th grade's final exam, my students lost will to study. Then I started to find something inspiring them and I reminded "Traffic Light Solution(In our country, we call it like this :D)" that I made in our university's conference. I tried with no specific recipe and I failed and I searched this video. Your instruction REALLY works. Now I'm getting more chemical knowledge from RSC. Thanks for a bunch of COOOOL stuff!
AND~ I have two Q.
Q1: Is there some specific concentration to make turquoise?
Q2: Is there some proper ratio between NaOH : Glucose?
+Terpsichore13th thanks for the feedback - check www.rsc.org/eic/2014/05/indigo-carmine-traffic-light-demonstration for further info. The trick to getting blue is working below pH 11.4 so you don't push that initial colour up into the green through the high pH. Use the 0.4M NaOH and add when adding the sodium hydroxide (changing from blue form) you need to stop adding just as it's about to turn green. You can tune the turquoise at which you stop to your own preference. If you added all the NaOH it would go to green (half blue/half yellow) but if you add a bit less then there is more blue than yellow so it looks turquoise. As for ratios .. well it depends what you want. The amount of NaOH will affect the colour of the dye from a pH perspective (see article) - the OH- ions are useful to us in assisting the formation of the aldehyde form of the sugar before being further oxidised. So playing with the ratios affects both the series of colours you get and the rate at which the whole thing proceeds (it's 1st order wrt both the glucose and the OH-. The ratio provided is a sweet spot for use with a class when you want it to do its thing 'on command' :)
The beauty of Chemistry....
what a wonderful idea sharing chemistry with the public.
Question: Will Chemiluminescence occur if one added some luminol to react with the hydroxide of the NaOH in the mixture with the diluted indigo carmine? In addition, Will one need a metal catalyst to activate the luminol?
Can you continue to change the color by shaking it? Or does it have a time limit before it becomes a dud?
I WANT AN ANSWER!
I found that mine stopped working after a couple of days. I'm curious to know why.
0olong thanks for the comment .. to be honest I'm surprised you got it to last that long :) As you can see in the attached article in the description , the glucose is constantly being reacted through to the final product, sodium arabinonate. Along the way there are two intermediates of relevance to the reaction and the most important one is the enediolate anion which reduces the dye. Eventually as the glucose is used up, no more of this anion is around to do it's job so the flask will stop working.
Thanks Declan Fleming! Your clear and concise explanation is much appreciated. :)
It probably only lasted so long because my lab was so cold.
"Jesus' magic makes the colors change, Science boy!" ~ Liberty University
thanks for the new great information
well this is awesome
this is great for a Titration
Is that a rumbling stomach I hear at 3:20?
Hitman Monkey haha it might be! Filming these videos alone often leaves me for long hours in the lab trying to sort out lighting, framing and focus and getting the reactions to work "just right" so sometimes my belly has to wait ;)
The girl to the left is feeling like a third wheel.. Not having alot of fun. ^^
It turns out that trying to juggle speaking to two people, whilst ensuring you say everything you need to say to camera in one take, whilst worrying if you're going to be asked to leave by the cafe owner is more difficult than it looks. I felt awful when I watched the footage back!
If you look at the article linked from the video there are some other dyes mentioned you can use. Most famously methylene blue
+TALENTED OSAS hopefully this prep will help? www.rsc.org/education/eic/issues/2006Nov/Exhibitionchemistry.asp
University of Whales ;)