It can take a while for water running from the tap to get hot. Yeah, you can wait around with your finger under the water, but it would be a lot easier if you could see when it's finally hot. This clever DIY temperature indicator lets you do just that. This video from the Shake the Future YouTube channel shows you how to create a simple temperature indicator for your tap that doesn't require any special tools, batteries or electronics. All you need is some clear nail polish and some thermochromatic pigment that loses its colour when it gets heated up. Remove the nozzle from your tap, paint it red and let it dry. Then mix the thermochromatic pigment with the clear nail polish, paint it over the red, and let it dry. The nozzle should now look blue in its neutral state. When you attach it back on your tap and try to run some hot water, the nozzle will turn red when it finally heats up. Now you can do other things in the kitchen while you wait to know exactly when it's ready. If you don't have a nozzle on your tap, you can follow the same process by making a dot somewhere on your tap instead.