This is a very simple project that will cause a lighter to either explode or shoot somewhere. All that is required for this project is a cheap plastic 50 cents lighter with an adjustable gas height switch.
Sorry I don't have pictures of me doing this. As you can tell from my other instructables, I don't like to post things that I don't have proof of doing myself, so you'd know that all my things are "Billy tested, mother approved". Its just that being in a dorm now, they are a lot more strict then at home, and they probably would not approve of setting fires in front of the building. Not only that, but the 911 call center for all of NYC is the next building over, and I'm pretty sure they wouldn't approve, they don't even allow people on the sidewalk in front of that building. So I guess the best thing that I can give you is my word that Ive done this project many times, its fun, and actually relatively safe compared to the other things I've posted.
Step 1: Prepare the Lighter
Remove the metal cover for the lighter. Underneath it should be the flame adjust switch, it is a plastic ring around a plastic piece screwed into the top of the lighter. Unscrew the plastic valve until you hear gas leaking out of it, without having to hold down the button. Make sure the gas leaking out is just a trickle, otherwise the lighter will loose too much gas for anything to happen. Spark the lighter once, it should ignite the gas leaking from the valve, and instantly drop the lighter on the ground OUTSIDE. After maybe half a minute, the flame from the leaking gas will melt through the plastic on the side of the lighter. The gas from the chamber will then escape out over the flame, ignite, and either cause the lighter to explode or propel it along the ground a few feet.
Step 2: Other More Dangerous Options
If your feeling more daring then waiting the 30 somewhat seconds for the plastic to melt, there is another choice. You need to open the valve a little more then in the last step, so there is a larger amount of gas escaping. There needs to be more gas escaping so the flame does not go out when you throw it at the ground. Ignite it, and throw the lighter away from you onto hard ground. The impact force will crack the plastic (if you threw it hard enough) allowing all the gas to escape at once and igniting it at the same time. The most common problem is having the flame go out while you throw it, the only solution is to throw it with just enough force to crack the plastic, but not so fast that it extinguishes the flame.
The most important thing to keep in mind is throwing it AWAY from you, meaning don't throw it down at your feet. Ideally you should have it hit the ground 15ft away from you, at that distance it would be almost impossible for anything to ricochet back and hit you. If you want to be super extra safe wear goggles while doing this.
If you are feeling really daring, tape one of the small butane refill cartridges (the ones shown in the photo) to the lighter. Ignite the lighter like in the last step, and throw the entire thing at the ground, making sure you throw it hard enough to crack the plastic butane case. It will give off a large flame and a loud whoosh.