Black or white

Spark and I have been reading about deserts and one of the things we read was that people in deserts often wear black because, although it heats up faster in the sun than white, it cools down faster after a person goes in the shade.  Really?  That didn't make a whole lot of common sense to us so we tried it out.

 

We got a black mug and white mug and put a cup of water in each one.  The temperature of the water in each mug was 50 degrees.  We put them out on the deck in the sun for an hour.  After an hour the temperature of the water in the black cup was 71 degrees and in the white cup 70 degrees.  Not real warm but it was late in the day and not very warm out so the 70 degrees was much warmer than the air was.   After we took the temps of the water we let them sit on the kitchen counter for an hour.  The temperature of the water in the black cup was 67 degrees and the white one 69 degrees.  So the book we were looking at was right, black does cool down faster than white.  If we hadn't done the experiment I don't think I would have believed it.