Temperature sensitive ink
We designed a marker to let users know when their hot beverage has cooled down. The ink changes from dark blue to green when a liquid enters the cup that is hotter than 150°F and changes back to dark blue when it cools back down to 150°F.
Our goal is to optimize the coffee / tea drinking experience by giving users visual cues of their drinks temperature. Like it hot? When ink fades to dark blue, start drinking up. Like it cooler? Wait till it reverses color completely. Drink completely cold? Microwave and see the ink change color to have a baseline of how hot your drink is. Know your drink's heat and enjoy every sip.
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