[TheNightBringer89]

Hey all, I need some help, keep in mind I know absolutely nothing about chemistry so this might not even be possible. I am a magician and I need to be able to have a number apear on my arm. Is there some kind of substance that would go on clear and change color after time, or by blowing on it maybe? Possibly heat sensitive so it goes on clear then when I hold a lighter up to it it will change color? Also note that it will be on my skin so it cant be toxic. Any and all help will be greatly apreciated.
Thanks in advance

- Corey <><

[hmx9123]

There are a number of solutions, depending on the color, time delay, and toxicity that you want to expose yourself to.  A great book for this is Chemical Magic by Leonard Ford.  I think Amazon sells it.  It's a Dover publication, so it's really cheap.  It's an old book from the 1940's, IIRC, so a few of the procedures aren't super safe (like the ether fire or the white phosphorous experiments).  However, the majority of the material there is pretty decent.  Almost all the color changing stuff is innocuous.  Take a look in there, and you'll find a treasure trove of material like what you're looking for.