True story: As a kid, my own father caused an explosion and small fire in his parents' basement while experimenting with his chemistry set. Such results would be nearly impossible to produce with current chemistry sets, which replace acids, explosives, and poisons with nonvolatile ingredients for growing crystals or making long-lasting bubbles.
American chemist John J. Porter is credited with creating the first toy chemistry set in 1914, and erector set inventor A.C. Gilbert introduced his own version in 1920 [sources: Hix, Zielinski]. Like erector sets, chemistry sets were designed to teach boys (yep, just boys) about science. They were marketed as a step toward a career in chemistry, and they included a whole lab's worth of equipment and materials, including heating elements, glass test tubes, and substances like sulfuric acid, poisonous sodium cyanide, and explosive potassium nitrate. Safety regulations of the 1960s and 1970s largely did away with "real" chemistry sets, although more inclusive kits have begun to make reappearances in the 2100s [source: Zielinski].
As for my dad and his 1950s vintage chemistry set, fortunately no one was injured, and his mother eventually let him back in the house.