Hello. Thanks for your review.
Color represent the temperature of the molecule. The closer it gets to red, the hotter it is. If it turns fully red, it will burns out (became black). If you try to cool it (by clicking on it click) when it is not hot (blue pallete) it will freeze (turn white).
So game loop is: cool it, to dont let it burn out (became black) while not over-cooling it to prevent freezing (turning white).