I'm building a little quiz game in Arduino and I already have it displaying a multiple choice question and people can answer by pressing pushbuttons.
But anyways now I wanted to know if it's possible for there to be an element (maybe some sort of metal or diode?) that heats up depending on whether you get the question right. So you would answer the question with one finger and put your another finger on the element to tell if you got it right. Obviously I don't want this heating to the point of actually burning someone, just enough so that they can tell if they got it right.
Also it would be cool if this same element would also be able to cool down (below it's initial temperature) if the answer is wrong. And obviously the heating up (or cooling down) has to be relatively quick, you can't be waiting a couple minutes. And as an added challenge I don't want this to be sucking up all my batteries
Any ideas about what this element / circuit can be?