Q:

Did Kirk really show how to make gunpowder in the episode "Arena"?

I remember seeing this episode when it was first aired. I was 13 and always wanted to get the charcoal, sulfur and saltpeter.

A:

Not quite.
While those are the proper components, his method was flawed -- this has been covered in multiple shows -- including the primary go-to for such things, Mythbusters. Unfortunately, I can't find a full video of the test. For that you'll have to go to the website.

