# Determine water temperature without touching the water

I've come up with a riddle that I use on a daily basis to solve a simple problem.

In a kitchen, you have a water tap that can run cold and hot water (or a mixture). The more fancy ones have a handle that can rotate in 360 degrees where horizontal movement determines the temperature, and the vertical movement determines the tap being on or off.

It is possible to determine how warm the water is without touching the water itself or using any device that measures the temperature that will work on most, if not all water taps (I have not found a tap where this did not work)

So, how can you determine if the water is cold, warm or hot without touching the water?

• Why was this question down-voted? Seems to follow the guidelines of the help center. Apr 28, 2020 at 10:50
• "Water crane"? Do you mean a tap - I doubt you are filling steam-powered locomotives... Apr 28, 2020 at 11:00
• @LPChip I'd guess you're Dutch. The Dutch word for tap/faucet is "kraan", and the same word is also used for the bird and for the lifting device. Apr 28, 2020 at 11:21
• @JaapScherphuis I am indeed. :) Apr 28, 2020 at 11:24
• @Chronocidal It's a nice descriptive word though :-) I understood immediately what it must mean. Apr 28, 2020 at 11:26