It was all in the name of fun... mostly. It was also one of the most memorable teaching experiences.

I thought I mentioned smoke bombs, but apparently not. They were a good litmus test to see if the boy could keep a secret. Following which were: Dry ice bombs. Thermite, Elephant Toothpaste. Napalm. Hydrogen gas explosions. (If you see a plastic bottle on your lawn filled with blue liquid, do NOT disturb. Call the non emergency police line.) Nitrogen explosions. (See 2020 Beirut explosion for visuals.) And a few other unmentionables that are much too easy to manufacture, one of which I saw in another's answer.

RDX (Royal Demolition eXplosive) is the oomph behind the plastic explosive C-4. It is slightly more explosive than C-4, because it hasn't been stabilized by anything.

All ended well and mostly good. Unfortunately I think I assisted the boy is believing breaking the law was fine so long as you don't get caught. Now I can't look at chemical formulae without my heart starting to pick up the pace. However, there were no injuries, no actual close calls except the spilled water when we started the dry ice. Following which the boy sat through several intensive lessons each on operations security, command structure and discipline, distractions, and safety. We learned safely, which is all that matters in the end.