You do not want to be messing around with KNO₃. A mixture of charcoal, KNO₃ and sulfur is EXPLOSIVE and can cause serious injury!!! GUNPOWDER!

If you want to explore the world of fast chemical reactions, I suggest you channel your efforts into a safe activity that still uses chemical reactions. One example would be model rocketry. Google search on ESTES industries or model rocketry and you will find places you can purchase rockets models that can be built; you can also purchase rocket motors to propel the rockets to 1000's ft altitude. But I reiterate again, fooling around with dangerous explosive chemicals can produce severe burns, loss of eyesight and broken ear drums as well as production of noxious fumes. You can lose a finger quite easily and its not worth it. BE CAREFUL. DO NOT FOOL AROUND WITH CHEMICALS UNLESS YOU TALK TO YOUR CHEMISTRY TEACHER. Some of these materials are illegal and they all are HAZARDOUS.