The Soap Explosion and Pyrotechnic Demos
Most recent answer: 10/22/2007
Q:
I would like to know how do you do the soap Explosion, i would like to show me studens it.
I am a teacher in physich and chemistry in Denmark at a high school.
I would also like to ask about some pyrotechnics experiments from you?.
Thank You
Karl Jensen
- Karl Jensen (age 28)
Kobenhagen west high, Kobenhagen, Denmark skandinavien
- Karl Jensen (age 28)
Kobenhagen west high, Kobenhagen, Denmark skandinavien
A:
Karl -
One question at a time...first, the soap explosion:
The soap explosion is really pretty simple. The difficult part is that it does require about a half of a gallon of liquid nitrogen. If you live near enough to a university, you may be able to get some from their physics or chemistry departments, and some hospitals and research institutions also use it for cryogenics. Unfortunately, though, if you can’t get any liquid nitrogen, I really can’t think of any other way to do this demo.
Next, put about four inches of warm water in the bottom of a bucket (larger buckets seem to work better, if only because they’re harder to miss.) Add some regular dishsoap - you shouldn’t need more than a couple of tablespoons. Set the bucket well away from your audience and just dump the liquid nitrogen in - the harder you dump it, the more bubbles you’ll get! Be prepared to get completely covered with soap!
Also, if you’re doing this indoors, find a room with a high ceiling and do it over a tarp (although it’s probably better to do it outside), because this does make a mess:
The explanation for this is that the liquid nitrogen is so much colder than the warm water that when it hits it, it evaporates pretty much instantly. This produces a lot of gaseous nitrogen which forms bubbles with the soap in the water.
Ok, now for pyrotechnics! I don’t know too many of these off the top of my head, but here’s one that I’ve heard is pretty cool:
Get a large glass bottle. It has to be glass, and I do mean /large/! About the 5 gallon size would be good. Make sure that the glass isn’t cold to start off with so that it won’t shatter when heated. Put some alcohol in the bottom of the bottle (methanol should work). Rotate the bottle around so that the /entire/ inside of the bottle is covered with a layer of alcohol.
Light the alchohol around the top of the bottle with a match and get out of the way! (So long has you’ve got a decent quality glass bottle, it shouldn’t break, but you really don’t want to get burnt doing this.) The burning alchohol will form a ring of fire around the inside of the bottle that will travel down the side of the bottle pretty quickly. It also makes an interesting sound as this happens. I’m not really sure how much in the way of physics this demonstrates, but it’s sure to get your class excited!
Good luck!
-Tamara
One question at a time...first, the soap explosion:
The soap explosion is really pretty simple. The difficult part is that it does require about a half of a gallon of liquid nitrogen. If you live near enough to a university, you may be able to get some from their physics or chemistry departments, and some hospitals and research institutions also use it for cryogenics. Unfortunately, though, if you can’t get any liquid nitrogen, I really can’t think of any other way to do this demo.
Next, put about four inches of warm water in the bottom of a bucket (larger buckets seem to work better, if only because they’re harder to miss.) Add some regular dishsoap - you shouldn’t need more than a couple of tablespoons. Set the bucket well away from your audience and just dump the liquid nitrogen in - the harder you dump it, the more bubbles you’ll get! Be prepared to get completely covered with soap!
Also, if you’re doing this indoors, find a room with a high ceiling and do it over a tarp (although it’s probably better to do it outside), because this does make a mess:
The explanation for this is that the liquid nitrogen is so much colder than the warm water that when it hits it, it evaporates pretty much instantly. This produces a lot of gaseous nitrogen which forms bubbles with the soap in the water.
Ok, now for pyrotechnics! I don’t know too many of these off the top of my head, but here’s one that I’ve heard is pretty cool:
Get a large glass bottle. It has to be glass, and I do mean /large/! About the 5 gallon size would be good. Make sure that the glass isn’t cold to start off with so that it won’t shatter when heated. Put some alcohol in the bottom of the bottle (methanol should work). Rotate the bottle around so that the /entire/ inside of the bottle is covered with a layer of alcohol.
Light the alchohol around the top of the bottle with a match and get out of the way! (So long has you’ve got a decent quality glass bottle, it shouldn’t break, but you really don’t want to get burnt doing this.) The burning alchohol will form a ring of fire around the inside of the bottle that will travel down the side of the bottle pretty quickly. It also makes an interesting sound as this happens. I’m not really sure how much in the way of physics this demonstrates, but it’s sure to get your class excited!
Good luck!
-Tamara
(published on 10/22/2007)