We built a evaporating-hand water clock using a WaterColorBot fitted with a Buddha Board. The Buddha Board is a black board with a gray ceramic coating that becomes transparent when wet, so you can paint on it with plain water to make black marks that disappear as the water evaporates. (And, it fits nicely in a WaterColorBot with the appropriate jig.)
As a clock, once a minute it draws the minute hand, then the hour hand, and finally the outline of the clock face.
As the water evaporates over the course of a few minutes, the old minute hands fade away. It’s a neat effect.
And of course, video:
Continue reading A WaterColorBot Water Clock