Color change Chemical reaction help

[jonathancohen]

I am working on a project that needs 2 chemicals to react and change colors. The catch is they most likely need to be or come in a powder form, non toxic, and relatively inexpensive.

PLEASE HELP!

 

[Borek]

To clarify: you want to mix two powders and observe color change?

 

[jonathancohen]

yes, that is correct

 

[jonathancohen]

...without heat

 

[chemisttree]

Try tumeric and methylene blue. Mix the yellow powder with the blue one and it turns green! How cool is that?