Chemically speaking, several things happen when the powder hits the acid. Any leftover magnesium powder reacts with the acid to produce hydrogen gas. The magnesium silicide reacts with the acid to produce silane gas, which spontaneously combusts on contact with air, giving off little pops that ignite the
nearby swirls of hydrogen gas.
If there is still some magnesium powder floating in the air, it catches fire too, creating a bright flash and a puff of white smoke. You get three forms of fire in one, and the powder falling to the bottom of the bowl is purified elemental silicon. Spells are fantasy, but potions are real, and this is a great one.
Click to see a reactive moment. Magnesium, hydrogen and silane burn off while the purified silicon falls to the bottom.
Theodore Gray is trained in lab-safety procedures. If you try this at home, you do so at your own risk. Find more info on Gray's scientific pursuits at periodictabletable.com.
Five amazing, clean technologies that will set us free, in this month's energy-focused issue. Also: how to build a better bomb detector, the robotic toys that are raising your children, a human catapult, the world's smallest arcade, and much more.