The changing coffee mug bargain
We've all seen a coffee mug that changes color when you put your warm coffee in it. Most certainly they're pretty cool looking, but I noticed they don't serve the primary job of a coffee mug--to hold your coffee and keep it warm as long as possible.
At first I thought my coffee might have been going cold so quickly simply because the mug had a larger diameter than my others, making there more exposed surface area for the hot coffee to conduct heat to the cooler surroundings. However, I have a coffee mug that would expose even MORE surface area than my fancy color-changer, and it seems to keep heat even longer.
So what's really going on here?
Actually, once it hit me the concept is pretty simple. The only thing that makes the black background turn into vibrant colors on the mug is heat. So clearly that heat is what's being taken to produce the color change. Speculation makes me think it may be like exciting electrons--different excited electrons, when they jump back down to where they're supposed to be, emit different colors. But I have no idea what these mugs are made of and they aren't actually GLOWING, so it could be something entirely different. Whatever the case, it's quite clear that the appearance of the colors are stealing the heat from the coffee too appear. So on top of the normal heat loss to the surrounding atmosphere, the coffee is also losing heat to make the mug look pretty.
A good bargain? I guess it depends on how fast you drink your coffee.
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