Color-Changing Markers Let You Know When a Hot Drink Has Safely Cooled

The markers used by baristas at coffee shop class to judge cup might soon be useful for more than just key out your boozing . enliven by the experience of burn your tongue on excessively hot coffee , theInk N Drink markerscontain heat - sensitive ink that let you screw which drink is yours , and if it ’s good to sip yet .

The marking write in blue ink , but when it ’s exposed to temperatures exceeding 150 degree Fahrenheit — like from a live drink inside a theme cup — it change to special K , let you know your boozing is too hot .

When it ’s cool sufficiently , though , the ink deepen back to blue so you know it ’s finally safe to chug without scalding your mouth . The $ 4 marking of course make on the paper cup used in popular coffee shops , but it can also work on ceramic fool too , reckon on how duncish the material is . If the heat from the drink is n’t in effect transferred to the outside of the loving cup , the ink wo n’t be able-bodied to do it ’s job . [ Ink N Drink ]