Before I was a teenager and well into my teen years we made and set off bombs and explosive devices that would get us long prison sentences today. Our parents and the local police knew what we were doing and didn't have a problem as long as we didn't endanger anyone or cause any damage.
I never had a chemistry set but several friends did. There were experiments that would scare people silly today. Chemical supply stores and some drug stores sold everything we needed to make gunpowder, guncotton and one time nitroglycerine. Sodium metal and calcium carbide could be used to create an explosion and fire projectiles. Now we can't even set off a firecracker.
"Now we can't even set off a firecracker."
As much as I hate to say it...considering that 90% of parents do not raise their children anymore it probably is safer for all of us that some of these things are not so readily available. :( I think that would change if someone actually held parents of underaged people accountable for what their children are doing.