Heat Sensitive Mug with a Smiley Face
This coffee mug reacts to heat. When hot water is poured inside, the color of the mug changes to bright yellow. This is no magic, this is science – the mug is painted with thermochromism paint (a type of paint that is sensitive to temperature).
What’s interesting about this particular mug is that before the color changes, you will only be able to see two comic looking eyes. When hot water is poured, the mug color changes to bright yellow and a smiley face will appear to brighten up your day.
The seller of this mug also has other mug designs with a similar feature.