Showing posts from December, 2020

Did You Get Your Magic Cup Yet?

  Last month, Starbucks introduced the holiday season drinks, a bevy of artisanal ceramic mugs, the Holiday Blend coffee beans, and the new color-changingcups . They start off green, and turn red when hot liquid is poured in. Regardless of how you celebrate the darkest days of winter, we all need a little magic in our lives. Even in the best circumstances, magic is a good thing, but now at the end of 2020, magic is much needed. I’ve always wondered about the science behind color-changing cups. The new magic cups at Starbucks are a perfect example of thermochromism and heat-sensitive paint. Thermochromism is the property of certain materials to change their color in response to a change in temperature. In this case, heat-sensitive thermochromic paint contains pigments that change color based on temperatures of about 60 degrees and above. Considering that hot coffee is usually served at temperatures of at least 90 to 100 degrees---and higher, serving coffee in these cups automatically