170 replies to this topic

[Chyros]

Good luck with that .


On another note: a friend of mine works in physical organic chemistry making organic substrates and has lots of colourful compounds, such as this one. Here you can see a beaker of one of his samples under a blacklight.

Explain what is happening here.

[Destiny]

Bio-luminescence!

[deltaepsilon]

Destiny, on 27 Oct 2010, 18:33, said:

Bio-luminescence!

It's like what happens to infantry poisoned with anthrax in Generals.

[Chyros]

Destiny, on 27 Oct 2010, 9:33, said:

Bio-luminescence!

No, I'm a chemist so of course it's chemiluminescence . But do go on . try to describe in your own words what's happening, and given that it's a completely organic molecule, try to come up with a way how it could be happening, too.

Edited by Chyros, 27 October 2010 - 15:35.

[n5p29]

is that fluorescent (that glow-in-the-dark thingy)?

[Chyros]

n5p29, on 27 Oct 2010, 17:49, said:

is that fluorescent (that glow-in-the-dark thingy)?

Correct ^^ . It's a fluorescent material. It's not glow-in-the-dark though, because this will not actually keep glowing in the dark. As soon as you take the beaker out of the UV blacklight it's under in this picture, it will stop emitting light. Glow-in-the-dark materials are phosphorescent; they release their light more gradually, and therefore will continue to glow even without a blacklight or comparable source.

[Destiny]

I guess the stuff inside are reacting each other which in turns produces light and heat and...stuff, and the blue coloration is because of...UV?

[n5p29]

Chyros, on 27 Oct 2010, 23:24, said:

n5p29, on 27 Oct 2010, 17:49, said:

is that fluorescent (that glow-in-the-dark thingy)?

Correct ^^ . It's a fluorescent material. It's not glow-in-the-dark though, because this will not actually keep glowing in the dark. As soon as you take the beaker out of the UV blacklight it's under in this picture, it will stop emitting light. Glow-in-the-dark materials are phosphorescent; they release their light more gradually, and therefore will continue to glow even without a blacklight or comparable source.

so the colorful glowing ring/tube toys, that usually found at night carnivals or concerts, are not fluorescent? o:

[Chyros]

Destiny, on 28 Oct 2010, 2:22, said:

I guess the stuff inside are reacting each other which in turns produces light and heat and...stuff, and the blue coloration is because of...UV?

Nah, it's not really a reaction - it's just a single compound in that solution. And though the UV does cause the blue colour - how does it do this?

@ n5p29: eh, it's time for some more formal terminology to explain this. It's neither fluoro- nor phosphorescent - it's chemiluminescent since the light comes from a chemical reaction between H₂O₂ and Ph₂(COO)₂. Fluoro- and phosphorescence emit light because they absorb light, not because of a reaction.

[Destiny]

Pigmentation? Or...stuff...IDK Maybe the chemical properties absorb all but blue and stuff...

[Amdrial]

Just a random guess: The substance contained within the glass refracts and reflects the light directed at the glass and reflects the light back at the (camera)lense which will as a result make it appear as if the entire substance is glowing? (Compared with shooting a narrow coloured laser at a crystal, which will in turn make the entire crystal glow in the laser's colour)

Edited by Amdrial, 28 October 2010 - 08:59.

[Chyros]

Hmmm, not bad guesses. Both of your guesses are important concepts in physics, actually. In this case, it's like this.

The molecules absorb energy in the form of UV light, which brings them into a higher-energy state. This higher-energy state relaxes back into the "normal" state with loss of energy, namely the light emitted from the molecule. Kinda like this (except not a laser but UV)

Edited by Chyros, 28 October 2010 - 19:30.

[Chyros]

Addendum on aqua regia:



In retrospect I found I had kept it a bit short .



Also, the reason why the organic molecule was fluorescent was because it has a highly conjugated system (many alternating double bonds) which allow it to take up and delocalise electrons easily. This excess energy is then emitted again in the form of visible light.

[Destiny]

That little jar was shaking so much I was hoping it would fall and

[Chyros]

It's very hard to do stuff while having only 2D vision . I can either look at camera footage and have 2D vision but at least keep the camera on target, or look at the thing with my own eyes (in 3D) and then the camera will start to wander off of what I want to film. I'm also very limited to what I can film since for most chem stuff you need two (or three or four or five or two dozen) hands.

If I made some kind of massive cockup I would just re-record the movie, though .

[BeefJeRKy]

I was thinking of energy levels myself

Also chyros, get a helmet cam

[Chyros]

We don't have helmets (well, we got blast shields, but I'm not going to use those ) but even if we did, I'd never get the cam on in such a way that I'd be able to film well what I was doing. Worse, it wouldn't be able to record sounds much at all.

I'll have to think of some other way, I guess.

[Destiny]

Tape it to the side of your head/blast shield?

[BeefJeRKy]

Pinning this

[Chyros]

Destiny, on 31 Oct 2010, 2:51, said:

Tape it to the side of your head/blast shield?

Nah, like I said, if you can't see what it's filming, you're inevitably going to get useless films. And you wouldn't hear a thing.

[BeefJeRKy]

Your next alternative is to have someone else film you

[Chyros]

The glow, the wonderful glow - can you not see it General?!

After a rather long pause here I'm gonna throw in a fun picture of a reaction done using a very powerful UV lamp. The lamp is so powerful that you need serious tinfoil to keep the light in otherwise everybody who gets near loses eyesight pretty immediately. The lamp also has to be cooled constantly because otherwise it would melt itself.

I have some more stuff in the pipe that I want to show, but first I need a video to explain the principles of it and I've tried four or five takes now which have all failed. I'm trying to get it on ASAP without too many messups in it .

[Destiny]

It looks very...evil

[TheDR]

That looks awesome!

Now if i could only incorporate that into a computer case...

[Chyros]

TheDR, on 5 Dec 2010, 17:20, said:

That looks awesome!

Now if i could only incorporate that into a computer case...

It would liquefy your computer .