I'm currently trying to refine my magic system which is able to manipulate the elements using the body's natural energy.
I can create water out of the air by coalescing available moisture in the air and/or combine the elements of oxygen and hydrogen to increase the volume created.
I can split and combine elements from compounds like carbon from charcoal and infuse it into iron to make steel.
I can manipulate the elements and compound to create shapes (mould a steel ingot into a gun barrel).
I can do anything that manipulates the elements as long as I have the necessary element or compound nearby, I cannot create it from nothing.
The difficulty is trying to understand how difficult these tasks should be. Assume for the moment that 1 joule of energy from the body can manipulate 20 joules of magical energy (Value for example purposes and not set in stone). We of course do not have an infinite amount of energy, assuming a level fit for a human and using it up would be like finishing a marathon at maximum effort.
How many joules (in bodily energy) would it require to manipulate the elements? From creating water or causing a breeze in the air to splitting/infusing elemental compounds. For example, would splitting carbon from steel take the same level of energy for infusion carbon into iron to make steel? Is there any reading material someone can point me to to give me a better idea? I'm no chemist so would need something not overly technical.
Lots of questions sorry but at the moment I'm trying to figure out how difficult it would be for my protag to craft a semi-modern gun in a period that's set somewhere similar to the middle ages. Please ignore other issues about gun manufacturing for now though, I've already got another post from a few days ago that went into that and other specific issues about this I think I'll ask in a new and separate post.
Edit: Had a lot of questions, narrowed down now I think? If not I'm really not sure how to narrow it further without missing important points.