I suspect this is result of the metal lining expanding when the hot coffee hits it. The metal will expand due to a temperature increase, resulting in less room for the water in the lining, pushing the water out the bottom of the cup. Interesting. Moral of this story? I'm a nerd. :-)
Tuesday, May 23, 2017
Coffee Mug Science
Each morning before heading to work I brew a pot of coffee for my wife and I and pour my serving into a travel mug and take it into the office with me. When washing the mugs in the sink, if they soak for too long, water is sucked up into the lining between the outer edge and the actual cup the coffee rests in. No big deal. What's interesting, however, is that the water doesn't directly drain out. It stays in the lining until I pour the hot coffee in. Once the hot coffee hits the inside of the mug, the water in the lining comes pouring out the bottom! The picture below doesn't do it justice. It shows water on the counter, but it is always interesting to me when I see it in action.