Sciencemadness Discussion Board - 2 quick, but rather random, questions

2 quick, but rather random, questions

AngelEyes - 19-2-2010 at 05:59

Hello everyone,

Got a couple of questions. One is a serious one, the other...well..not so serious

1. This summer I am planning a party with drinks in the garden, etc, and I want to have something a little different. I was thinking a fire (I have a big copper firebowl) but using logs soaked in various salt solutions so they burn nice colours.
I would like green, blue, red...and maybe purple and white too.
What I have so far is:
Green - Barium Chloride
Blue - Copper Chloride
Red - Strontium...but I only have the Carbonate
Purple - a K salt...I only have chlorate currently - not lighting a piece of wood soaked in that!
White - any ideas?
So...firstly would anyone recommend any other salts to what I have there, and secondly how toxic would the smoke be from a Barium impreganted log? Dangerously toxic...or 'so long as you don't breathe the smoke you'll be fine' toxic?

2. My other, less serious question, is about farts. I pumped one out the other day that was exceptionally eggy. I mean, proper whiffy. So it must have had a fair concentration of H<sub>2</sub>S in it...yet the msds states that above 150ppm there is rapid loss of sense of smell. Yet this bad boy lingered for well over a minute - could there really only have been <150ppm H<sub>2</sub>S?

Thanks

Angel

12AX7 - 19-2-2010 at 10:03

1. Volatile salts will do better... copper chloride is volatile enough to evaporate quite effectively in a wood fire. You'll get blues and turquoise greens, inconsistently, depending on temperature and whatnot.

Lithium may be better than strontium for red, and you'll want to turn that carbonate into chloride.

White -- I've actually found lead chloride produces a whitish color, but I wouldn't recommend that, nor would I recommend barium for the same reason, they're both about as poisonous. If people can stay out of the smoke, it doesn't matter much (fence around the firebowl?). Magnesium metal would be much more exciting.

A vacuum-KClO3-impregnated log would be very interesting indeed. It would probably smoulder a lot though, since you probably can't get enough KClO3 into it to burn at once. It would also have to dry a looong time. Barring that, ordinary KCl will suffice.

Don't forget our friend sodium for brighter yellows.

As for H2S, the threshold is in the low ppb range, so where a weak fart is just slightly stinky, you can easily smell 10^5 times more H2S before you don't know it anymore. Of course, by that point, you're liable to die by your own farts.

Tim

argyrium - 19-2-2010 at 10:51

Halides of those you list will be the best. You might consider some HCl on the SrCO3 to make some chloride. The problem with good colors on logs is the carbon in the flame; the yellow tending to mask most other emissions. Other naturally occurring mineral salts will also interfere with good colors.
Try boric acid for green.

The best, fairly clear colors are obtained by burning methanol containing these salts.
Try some in little stainless bowls or possibly even Pyrex "custard" cups.

Argyrium

AngelEyes - 20-2-2010 at 04:43

Parts per billion? Wow...that's a big presence for such a small amount of gas!

As far as the other suggestions go, I like the Boric Acid for green - forgot about that.
And I realise the logs themselves will give off unburnt carbon and lots of orangey/yellow...and that's fine...I just want these logs to also give off bits of other colours so guests go 'ooh, ahh' etc.

Mg metal, more exciting certainly, but I don't want to blind people...plus I don't want to melt the firebowl!

So copper chloride a definite. I like a mix of blues and greens, that'll be fine. Lithium if I can find it, strontium (turned to chloride) if I can't for the red. Boric acid for the green. I don't think I'll need more yellow but Sodium, obviously, for that. K halide for purple if I can source it. Probably have to forget about the white I guess...

Thanks

Angel

pantone159 - 20-2-2010 at 07:02

I don't think B(OH)3 by itself will do anything, at least in my experience. The green color comes, I think, from the methyl or ethyl ester. I have tried tossing powdered boric acid into a fire and absolutely nothing interesting happened.

ScienceSquirrel - 20-2-2010 at 11:53

Methanol reacts quite readily with boric acid to form methyl esters.
Stirring a mixture of the acid and methanol on a hot water bath results in the acid rapidly disssolving and esters are formed.
If you pour the mixture in to a tin can and ignite it lovely apple green flames are produced.

woelen - 20-2-2010 at 13:30

The flames of the methyl ester of boric acid are really nice pure green.

http://woelen.homescience.net/science/chem/exps/borate_ester...

Unfortunately, the fire does not last for a long time. What you could try is dissolve a few grams of boric acid in a few hundreds of ml of methanol and soak some dry wood with this. Store the wood with the methanol in it in a closed bucket for a few days such that the methanol really is drawn into the center parts of the wood. Such wood will certainly show green color when it is burnt, but I do not expect a pure green fire.

A very nice thing, however, is to take a little alcohol burner and fill this with methanol in which some boric acid is dissolved. You can light this and put this on a table as an alternative candle. The flame from this is really green, like the flames I show in the videos of the webpage, given above. Besides that, such flames can burn for a long time, one such an alcohol burner can burn at least two hours on just 75 ml of methanol.

Keep in mind that boron is somewhat toxic, there is no problem at all to use this can of green 'candles' on a nice summer evening outside. Breathing a whiff of the vapor is not a problem at all. But I would not use such 'candles' inside during a winter evening party.

AngelEyes - 9-7-2010 at 06:02

Right...so I had the party and it all went well. I didn't use soaked logs in the end, instead opting for small steel bowls filled with methanol / colourant mix, and some ceramic fibre wool as a wick. It worked great. I had green (boric acid) and blue (copper nitrate + a little methylene chloride). Couldn't get red to work (used both strontium carbonate and nitrate) instead got a rather dirty orange, and the purple I tried (kno3) was a washout. But everyone was impressed with the green and blue so that was fine.

Turns out my neighbours are more into playing with fire than I thought so I am considering doing something a little more combustion-orientated for November 5th (Guy Fawkes night for our non-UK friends) but without using just fireworks. I have a few ideas, but if anyone else has any more then I'm all ears.

Ghost mines.
A couple of these should be good. Standard green or blue methanol mix in a bowl or tube, and then a lift charge (with some sponge Ti or flake Al in it) to 'make it go'. Should get a few 'ooohs' and aaahs' from the crowd!

Flame trail.
Make up several mixtures and lay them in a trail (maybe several feet long) so that when lit at one end it burns from blue to red in a line, like a rainbow or something.

Burning various metals
Everyone has seen Mg burn, but not many have seen Aluminium burn, or zinc, or sodium etc. Might set up a few of these on some concrete slabs, should be good to light up the garden!

Gas in a balloon
Take some balloons and fill them with various mixes (pure H2, mix of H2 and air, mix of H2 and O2, etc) so the difference between pure and optimally fuelled can be spectacularly demonstrated.

...but that's all I got. I am trying NOT to use explosives (like NG or NC etc) as they're inherently dangerous to use in a back garden, but obviously I do need something to excite my guests. So...any other ideas? Chemiluminescence (sp?)maybe? I have access to some raw materials but I don't work in a lab or anything so can't get anything too exotic.

Thanks for any and all suggestions.

Angel

densest - 9-7-2010 at 07:34

@angel - when you tried strontium compounds, did you add a chlorine donor? The deep red color comes from the SrCl molecule, not Sr++. I forget whether it's SrCl+ or SrCl2 which is the emitting species.

Lithium *without* chloride in methanol makes a nice red flame - slightly different color though.

AngelEyes - 9-7-2010 at 07:50

Yes, in the solutions where the metal salt was not a chloride I added a splash (maximum 5 or 10% by vol) of methylene chloride to act as a donor. This worked real well with the copper nitrate (I had a great blue when it got darker) but seemed to have no effect on the Sr or K salts.

Sadly, I don't have any Li salts otherwise I would have used them. Are they available OTC anywhere?

Cheers

Angel

watson.fawkes - 9-7-2010 at 15:24

Quote: Originally posted by AngelEyes

Burning various metals
Everyone has seen Mg burn, but not many have seen Aluminium burn, or zinc, or sodium etc.

Don't forget steel wool.

LiCO3 is generally available at pottery suppliers as a glaze additive.

zed - 12-7-2010 at 13:57

If you really want to impress, black flames would do the trick.

Unfortunately, black fire is not readily accessible on this plane of creation.

Other colors are available from your local or mailorder, pyrotechnics supplier.

http://www.firefox-fx.com/chemicals.htm

You are kind of a long ways off. Shipping charges would probably make Firefox an impractical supplier for you. Were shipping costs not an issue for you, I'm quite sure that if they had an extra neutron bomb laying around, they would be quite willing to send it to you.

Good folks.

Oh, by the way....A balloon filled with a mixture of H2 and O2?

That would be a bomb! Yup. Any spark, flame, or catalyst....and blammo! Violent explosion.

[Edited on 12-7-2010 by zed]

12AX7 - 12-7-2010 at 14:36

Quote: Originally posted by zed

If you really want to impress, black flames would do the trick.

Unfortunately, black fire is not readily accessible on this plane of creation.

I expect some Lucas electronics could help you with that goal.

Tim

Formatik - 13-7-2010 at 09:38

Quote: Originally posted by AngelEyes

Sadly, I don't have any Li salts otherwise I would have used them. Are they available OTC anywhere?

Lithium hypochlorite is used as a swimming pool disinfectant.

Hypergoles are another option, using KMnO4, KClO3, NaDCC, etc. as oxidants. A mixture of KBrO3 and sugar (must be ground separately!, then mix them together on a newspaper or paper) that has a drop conc. H2SO4 added to ignite it would work well in the night making a blue white near flash. Here is a mixture of 0.3g KBrO3 mixed with 0.1g cane sugar (not stoichiometric) igniting from a drop conc. H2SO4: http://ifile.it/8ngeld6

Compared to 0.3g KClO3 with 0.1g cane sugar ignited from the same acid (flame is purplish orange, burns a bit slower): http://ifile.it/s05nuba

Pictures of the same reactions are below.

Alexein made 2L soda bottle sized glowing sticks, you could put the resources into the precursors, even much more effort it would be to make these oneself: http://www.youtube.com/watch?v=mUCdGMeTveM

KBrO3-and-KClO3withsugar.png - 230kB

Formatik - 29-7-2010 at 22:52

Quote: Originally posted by Formatik

Lithium hypochlorite is used as a swimming pool disinfectant.

A note on this. I have some LiClO which was sold as a hot tub and spa disinfectant (may have gotten it from a pool/spa supply, don't remember). The purity was claimed 30%, the rest of the ingredients not specified. I tested to see if I could get red flame color, but the material only deflagrated with an orange color when held on a burning match. Higher purity will be needed then.

Fire Demo

sargent1015 - 30-4-2012 at 20:04

Quote: Originally posted by zed

Oh, by the way....A balloon filled with a mixture of H2 and O2?That would be a bomb! Yup. Any spark, flame, or catalyst....and blammo! Violent explosion.

Actually this mixture is substantially less explosive than just plain H₂ gas in a balloon. My student outreach group on campus in Madison actually does this demonstration, so don't worry about the entire neighborhood going up in flames

Endimion17 - 1-5-2012 at 06:11

Quote: Originally posted by sargent1015

No, it isn't. Stoichiometric mixture of hydrogen and oxygen is notoriously known for its violent detonations.

Flames are not something to be worried about when dealing with small amount of hydrogen. It is very light, dissipates easily, burns quickly or detonates if mixed with air/oxygen. It's not pure butane which deflagrates with a diffused yellow fireball.
The flame is short lasting and invisible, if hydrogen was pure.
Detonation is the problem.

The baloons your group makes obviously don't contain the proper mixture because hydrogen seeps out of the baloon fairly quickly, in a matter of minutes.
Freshly prepared mixtures are extremely violent.

mycotheologist - 1-5-2012 at 06:18

A bit of elemental Mg will make brilliant white flames. So brilliant, it'll blind everyone if you use enough of it lol.

Quote: Originally posted by ScienceSquirrel

Methanol reacts quite readily with boric acid to form methyl esters.
Stirring a mixture of the acid and methanol on a hot water bath results in the acid rapidly disssolving and esters are formed.
If you pour the mixture in to a tin can and ignite it lovely apple green flames are produced.

I wanna try this since I have 1kg of boric acid, but no uses for it. It is a reaction between the esters and the tin that produces the green flame? Reading threads like this makes me wish I was living in the country so I could play around with pyrotechnics and do all the experiments I like without worrying about the neighbors calling the fire department in response to seeing smoke, coloured gases or flames etc.

[Edited on 1-5-2012 by mycotheologist]

ScienceSquirrel - 1-5-2012 at 06:27

The tin is just to hold the burning mixture.
Boric acid readily reacts to form trimethyl borate that colours the flame.

sargent1015 - 1-5-2012 at 10:12

Quote: Originally posted by Endimion17

The baloons your group makes obviously don't contain the proper mixture because hydrogen seeps out of the baloon fairly quickly, in a matter of minutes.
Freshly prepared mixtures are extremely violent.

Then I'm glad our balloons don't contain stoichiometric amounts

Anyways, tried and true method supported by FST and NSF, if it wasn't safe, we most certainly wouldn't be doing it.

I'll look it up for you later tonight

-B

Alright, this method also applies for Hydrogen balloons. Hydrogen balloons are substantially more explosive than the mix (Bigger fireball). Make sure to do this in a room with high ceilings or outside with no wind:

Combine equal amounts of hydrogen and oxygen in a balloon, tie to a string and weight it down properly. It is important to note that static discharge at this point IS a problem! Be very careful, specifically, do not tie the balloon between your legs or transport the balloons via car. Make sure the string length is sufficiently long enough that you can reach the balloon with a meter stick. Attach a candle to the meter stick as well. The best way I have seen this done is by duct taping a 3-prong clamp to the stick, then you can easily change out candles.

Light candle, explain Hindenburg Explosion, make sure ears are covered and of course eye protection... AND light!

Loud bang, cloud of flames, children and adults love this!

Once again, I am referencing a demo that we do here on the UW-Madison campus. It has also appeared in the demo shows of the great Bassam Shakhashiri, genius!

Please be safe and smart when handling hydrogen gas

-Brendon

[Edited on 2-5-2012 by sargent1015]

[Edited on 2-5-2012 by sargent1015]

AJKOER - 1-5-2012 at 17:35

Actually, when I was a kid I managed to slightly damage the hearing in one of my ears by setting off an obviously too large H2/Air mixture (think plastic trash can). So fire and toxic fumes shouldn't be your only concern.