I never had one of these, but one of the earliest gifts I remember from my grandfather was a chemistry set which came with all the necessary chemicals to easily

I never had one of these, but one of the earliest gifts I remember from my grandfather was a chemistry set which came with all the necessary chemicals to easily create a wide variety of poisonous and otherwise dangerous (explosive / flammable for example) substances. The book that came with it was very explicit about those dangers and explained clearly what one should do to be as "safe" as possible about working with those chemicals. Fun times. Truly educational toys are just the best.