This is simple simulation how to determine acid or base of the solution, based on changing the litmus color. Basically, if the solution is acidic, the solution can redden blue litmus. And if the solution is base, the solution can be blueing red litmus. Based on the condition, then if the litmus paper dipped into the solution, we will be able to identify whether a solution is acidic or base. For new version we has changing the background to green color, since to most viewing the solution color. Please try it and have fun!