Archive for June, 2008
The Martini-Glass-of-Science and I spent some quality-time in the kitchen this morning making a video of a mad scientist potion. I also wrote up instructions for making the fizzing potion change color. Of course, if you really want to play mad scientist, add dry ice to the liquid.
Yes, of course you can make your own smoke bomb, but not everyone keeps potassium nitrate around the house, so you may want to visit a freworks store to get smoke bombs. They come in various shapes and sizes. The little smoke balls produce brightly colored smoke, but they only last a few seconds.
Bigger smoke balls will last a bit longer (about 30 seconds). Smoke grenades and large smoke bombs can last for a few minutes. Colored smoke is produced by heating and dispersing organic dye into the air, not usually because the ingredients actually burn a different color, so if you make your own colored smoke bombs, the key to success is forcing the colorants through an aperture.
If you add Mentos candies to tonic water and illuminate the event with a black light, you’ll get a glowing blue fountain. My advice: use diet tonic water unless you want a sticky mess.
You can open a beer, root beer, wine, or other glass bottle with a butter knife. All you have to do is hit it with a butter knife just under the lip of the bottle. The glass will shear cleanly, without sharp edges if you do it right. You can shear the neck of an empty glass bottle too (which is what Ry is doing here), but it works a lot better if you remove the label first (not necessary for a sealed bottle).
That’s also my first-ever YouTube video. I either need to figure out a way to mute my cellphone or camera or else strip the audio track (couldn’t find a converter for 3g2 to avi format). Suggestions are welcome.
Gunpowder or black powder is a mixture of sulfur, charcoal, and potassium nitrate (saltpeter) that has been used since the 12th century for fireworks and later as a propellent and explosive in weapons. It isn’t particularly efficient or safe for use in weapons, plus it produces a lot of smoke, so black powder has largely been replaced for those purposes by other compositions (e.g., pyrodex, shown in the photo), but black powder still has its place in pyrotechnics and as a propellent for certain firearms. You should know how it is made for historical reasons if nothing else. As with my ammonium sulfide stink bomb, if you decide to try these instructions yourself, use proper safety precautions. Be advised that the main problem with black powder is its tendency to ignite from static electricity. Keep this in mind and only use wooden or clay tools (e.g., wooden salad bowl). Store gunpowder in paper or cloth, never plastic (which may build up static).
Black Powder or Gunpowder Ingredients
The usual mixture consists of 75 parts potassium nitrate, 15 parts charcoal, and 10 parts sulfur.
- 75 g potassium nitrate (KNO3, saltpeter)
- 15 g charcoal (ideally from burning the wood of a willow or linden, but other sources work)
- 10 g sulfur
- distilled water
Making the Black Powder
There are different ways to do this. One is to mix the dry ingredients in a ball mill (like a rock tumbler) with lead balls (not steel! they can spark), run the ball mill about 2 hours, then filter the resulting black powder through a strainer so that the lead balls are retained in the strainer and the black powder is collected onto newspaper or cloth. The black powder is wrapped up and stored in a cool, dry place until use.
Since not everyone has a ball mill, the most common way to make black powder yourself is to do this:
- Grind each ingredient separately until it is a very fine powder. I recommend using a mortar and pestle for this, which you can get at any cooking store. If you are grinding each ingredient using the same bowl, rinse it out when you switch chemicals. (Traditionally you would add a little water or wine to dampen the ingredients and grind them all together at once, but that’s unnecessarily risky, in my opinion.)
- Boil your water.
- Put the potassium nitrate into the bowl. Add just enough boiling water to thoroughly wet it.
- Add the sulfur and charcoal.
- Stir the mixture for several minutes. It should be uniformly black.
- Allow the mixture to air dry. This is usually done outdoors on a warm, sunny day. Some people prefer to spread the mixture out onto newpaper to dry. Others mix in a bit of alcohol to speed the evaporation of the water. You don’t want to over-dry the black powder, since that will lower its effectiveness.
- When your black powder is dry, wrap it in paper or cloth and store it until use. This should be obvious, but don’t store it near heat or flame. If you make multiple batches of black powder, it’s not a great move to store it all packed together.
Black powder is used to produce a loud ‘bang’ in fireworks and as a propellent. Yes, it can explode, but so can a can of cola in your freezer. I’m not saying making it is risk-free or smart, just that black powder is mainly used for entertainment purposes, not destructive purposes. Now that you know how to make black powder, my next post will explain how to make a basic firework using it.
Friday was the last day of school for my kids. To commemorate the event, I posted a couple of safe recipes for stink bombs on my site and gave them permission to make the stink bombs as long as they did it at home and not at school. The recipes I posted are a little different from what you would get if you buy a stink bomb at a store that sells pranks and tricks. Those stink bombs usually release ammonium sulfide, as opposed to a hydrogen sulfide (rotten egg) or assorted sulfurous compounds (burning hair and rubber). You can make ammonium sulfide yourself, but it’s not a particularly advisable project. If you do proceed with this project you need to heed the safety precautions on the bottle when using ammonia (i.e., don’t intentionally breathe it; work in a well-ventilated area). Also, be aware that commercial stink bombs only release a very small quantity of diluted ammonium sulfide (1-2 ml). While ammonium sulfide stink bombs, like rotten eggs, are relatively safe, ammonium sulfide can be toxic and flammable (here’s an MSDS).
Ammonium Sulfide Stink Bomb
- 20 matches
- 1/4 cup of household ammonia
- Use the knife to scrape the material from the match heads into a jar.
- Add 1/4 cup of ammonia.
- Close the jar and allow the mixture to sit undisturbed at least a week.
- Open or smash the jar to release the stink.
Ammonium Sulfide Safety
Did you read the part about toxic and flammable? Ammonium sulfide and hydrogen sulfide (formed when the ammonium sulfide is released into air) are toxic in relatively low doses. Don’t use this sort of stink bomb in an enclosed space. Don’t make or use this stink bomb anywhere near a source of heat or flame. Ideally, only use these instructions for informational purposes. I consider this project to be something worth knowing, but not something I would do. So why post it? Because you’ll find the instructions elsewhere on the internet without the warnings. Hopefully if you read mine and decide to proceed with the project, you’ll at least use safety precautions. Ideally you’ll see why it’s better to just throw a rotten egg or buy prank stink bombs.