What are some free or commercially available simulation programs? The simulations I'd like to run would be related to spark discharge, electromagnetism, general chemistry, metal alloys, diamagnetic levitation, and such. It's nice knowing the formulas and theories behind stuff, but it'd be much nicer being able to see it happen without needing the equipment to do it live. I'm not looking for simple programs like those available by PhET Interactive Simulations. For example, PhET has several electromagnetism simulation programs, but those don't allow you to change the amount of current going through the wire, change the core material, height, diameter, or shape, go beyond four windings, etc.. I'm not expecting programs like those used to accurately simulate the big bang on supercomputers, either. I'm also open to some kind of sandbox simulator where I put in the formulas for gravity, magnetic flux density, ionization energy, or whatever else is necessary. Lists of programs or ideas for searching for them are both welcome.