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Wet Plastic

May 24, 2018

Why do some things dry in the dishwasher while others stay stubbornly wet?


(Stephen Worden / Radio Newark)

(Stephen Worden / Radio Newark)


Plastic that’s all wet. I’m Bob Hirshon and this is Science Update.

WIZU radio station manager Steve Worden in Newark, Delaware noticed that his dishwasher dries some items better than others.


The plastic dishes have beads of water all over them, but the china dishes are perfectly dry. Why is that?


We asked material scientist and author Ainissa Ramirez.

AINISSA RAMIREZ (Science Underground podcast):

It ends up that these items are experiencing the same temperature in a dishwasher, but they each have a different level of hotness.


She says the technical term is heat capacity, and it means that it takes a lot more energy for a plastic item to feel as hot as a ceramic one. As a result, plastic stays cool under conditions that get ceramics hot enough to evaporate water droplets. If you’ve got a science question, call us at 1-800-WHY-ISIT. If we use your question, you’ll receive a fast-drying Science Update mug. I’m Bob Hirshon, for AAAS, the science society.

Story by Bob Hirshon