On/Off Mug

INVENTION IDEAS : On/Off Mug

At first, I doubted whether this really existed. This is one of those out-of-this-world invention ideas. But yeah, the On/Off Mug really does exist! So what's so special about this mug? When it's empty, it's a plain black mug with the word OFF written on it, but when you fill it with your favorite hot beverage, it changes from black to white, and the word OFF changes to ON. Unbelievable? This is what I thought so at first, but it has a scientific explanation guys. This clever mug has a heat sensitive pigment that accounts for the change. Talk about amazing! It's pretty affordable too, it's sold for only $25 at Charles & Marie. Wow your friends and family with these cool inventions!