Introducing the study of chemistry with a bang with Mr. Ward.  Wearing proper safety equipment, of course, we combined hydrochloric acid with aluminum foil. The reaction started slowly, but generated heat that sped up the process of breaking off the hydrogen from the acid while dissolving the aluminum as it formed aluminum chloride. We captured the hydrogen in balloons and then applied an energy source (fire) to get it to combust with the atmospheric oxygen surrounding the balloon.  The result?  A nice orange boom and brand new water from the oxidation of the hydrogen gas.