j_sum1
Administrator
Posts: 6372
Registered: 4-10-2014
Location: At home
Member Is Offline
Mood: Most of the ducks are in a row
|
|
How to make a smoke match or smoke paper
I was wondering if I could have a bit of help:
I wish to demonstrate convection currents to a junior science class. I have come across some things called smoke matches, which as far as I know are
not available where I live -- at least not at short notice.
I would like to have something flammable, safe and smokey that I can use for the demo -- maybe impregnate some filter paper with something so that it
produces copious quantities of smoke.
Looking for some good suggestions.
(Probably a good thing to have on hand for checking lab ventilation and fume hood operation as well.)
|
|
|
Twospoons
International Hazard
Posts: 1349
Registered: 26-7-2004
Location: Middle Earth
Member Is Offline
Mood: A trace of hope...
|
|
Try cotton wick soaked in potassium nitrate (and dried, of course). It will smoulder steadily for quite a long time. If you used the wide flat wick
thats used in oil lamps you should get a decent amount of smoke.
[Edited on 7-2-2025 by Twospoons]
Helicopter: "helico" -> spiral, "pter" -> with wings
|
|
|
Sulaiman
International Hazard
Posts: 3779
Registered: 8-2-2015
Member Is Offline
|
|
https://en.m.wikipedia.org/wiki/Smoke_bomb
safer may be an ultrasonic water mister
as a youth : damp sawdust + saltpetre
mixing ammonia and hydrogen chloride vapours
joss sticks
a lit cigarette?
PS fire makes heat, which causes convection currents of its own.
[Edited on 7-2-2025 by Sulaiman]
CAUTION : Hobby Chemist, not Professional or even Amateur
|
|
|
Fulmen
International Hazard
Posts: 1748
Registered: 24-9-2005
Member Is Offline
Mood: Bored
|
|
The simplest method will probably be the KNO3/sucrose-mix: https://pyrodata.com/PyroGuide/index.php%5Etitle=Smoke_mix.h...
We're not banging rocks together here. We know how to put a man back together.
|
|
|
Morgan
International Hazard
Posts: 1728
Registered: 28-12-2010
Member Is Offline
Mood: No Mood
|
|
I once tried a light source from about 5 meters away from a lit small butane torch whereupon the shadow cast on the wall showed the convection
currents quite nicely, yet not all that exciting for students. Sort of like this image illustrated with a match and jet of hot gases. I've often
wondered if the effect shown here could be captured merely with a shadowgraph effect.
Jam Jar Pulse Jet Schlieren
https://www.youtube.com/watch?v=q1LQ94pjUWE
A simple demo but could use more smoke
https://www.youtube.com/shorts/7NF4kWJcFXo
With a smoke match but maybe the candle could be closer to the exhaust port.
https://www.youtube.com/watch?v=XVAI3tYzhqE
[Edited on 7-2-2025 by Morgan]
|
|
|
Belowzero
Hazard to Others
Posts: 174
Registered: 6-5-2020
Location: Member Is Offline
Member Is Offline
|
|
50:50 ammonium nitrate and sugar absorbed into paper gives a very nice thick white smoke when lit.
Just dissolve it into a little water and let the paper soak and dry.
It tends to burn a little too well, this can be controlled some what by rolling it up.
The ratio can be shifted to make for a slower burn.
Smells rather nice and the toxicity should be quite low as far as burning things go.
|
|
|
j_sum1
Administrator
Posts: 6372
Registered: 4-10-2014
Location: At home
Member Is Offline
Mood: Most of the ducks are in a row
|
|
Thanks belowzero. I ended up with something similar: paper towel soaked in a solution of KNO3 and dried. A rolled up wad of this produces more smoke
than flat paper.
Paper ended up more reliable than cotton wool. I did not have any wicks of the kind twospoons described.
If I get a chance today I will try ammonium nitrate and see if that is better. The KNO3 sputters a little.
|
|
|
Axt
National Hazard
Posts: 860
Registered: 28-1-2003
Member Is Offline
Mood: No Mood
|
|
I'm going back to being a kid here, I'm not sure what it was about newspaper, but soaking newspaper in AN-water was the way I used to make smoke bombs
25 years ago, back when AN was freely available to any kid walking into the farm store.
If you are up for experimentation try ammonium perchlorate and sulphamic acid 58:42 as a powder, I guess less sulphamic acid if soaked into paper.
Other perchlorates/chlorates would likely work too, just increase the fuel load to tame it.
[Edited on 9-2-2025 by Axt]
|
|
|
![[*]](images/xpblue/default_icon.gif){kind=icon}
