For a brief description please watch this video:
Note: Alot of people have mistakenly claimed that I have stolen video and pictures for this Instructable. To clear everything up, I didn't steal anything, I simply posted elsewhere long time ago, and eventually it became popular on the internet. Look in the beginning of the video for the signature.
Step 1: Materials
Before we start, I must warn you. This is obiously NOT a safe experiment you should allow small kids to make, as this will combust with an explosive-like effect with a drop of water, and might not always go off the way you want it to. This mixture is hygroscopic (will soak moisture from air) because off the ammonium nitrate included. So if it is very humid or raining, making this is not a good idea.
Okay, so let's get started!
For this project we will need following items:
- An "Instant cold pack"
- Table salt
- Zinc powder (grey metal powder, can be bought from unitednuclear.com or inoxia.co.uk)
Further you'll need
- A scale, preferably precise to 0.1g
- A mortar and pestle to grind the mixture
Step 2: Ammonium Nitrate
Start by cutting open the Instant cold pack. You'll notice there are two things inside:
- A bag of water, that you can throw away.
- White granules, consisting of ammonium nitrate.
We want the ammonium nitrate for this project, as it will act as oxidizer.
Step 3: Grinding
Now we will need to weigh out the following:
- 3g Ammonium nitrate
- 0.5g Table salt
Transfer it into the mortar and pestle and grind, untill it's well mixed.
Now comes the part were you need to take precaution, weigh out:
- 7g Zinc powder
Put it in the mortar and pestle and grind it together with the other ingredients.
Care must be taken at this point, not to let any water near this stage, since the powder is now finished and ready to use. Use it instantly, as storing the mixture will guarantee problems.
Step 4: Igniting
The only thing left to do is to ignite it.
To do so, add a few drops of water with a syringe or pipette (or stand well back and see if you can hit it with spit!)
The important thing is to wear safety gear, such as goggles or gloves.
A few seconds after the water is added, smoke will appear, and then a combustion will occur with a bright, green flame.