A capped 2-liter plastic bottle containing a clear, colorless liquid is shaken. The liquid turns a deep blue color. At rest, the liquid returns to colorless. The cycle can be repeated many times. Ask ...

For example, an out-of-the-blue email from a once-upon-a-time airplane seatmate recently inquired what a particular bottle of wine may be worth and if there was a way to sell it. Our initial ...