The marker writes in blue ink, but when it’s exposed to temperatures exceeding 150 degrees Fahrenheit—like from a hot beverage inside a paper cup—it changes to green, letting you know your ...

This article is more than 5 years old. Scientists in Germany have developed three different tattoo dyes that change color based on the levels of certain health markers in the blood.

Making this Color Change Chameleon is a fun way to add color to any day. You’ll need: 2 paper plates, markers, a ruler, a craft knife, glue and a brad to hold the plates together.

These products promise to change color in response to certain disease markers in a cat’s urine, to help owners spot early signs of illness before more serious symptoms arise.