Brains Not Brawn – Expansion and Contraction of Matter


Two of my favorite bowls got stuck together the other day. I had a goodbye dinner with friends and family for my daughter who was going back to her job in Thailand after a 6-week holiday in the States.   We had a lot of food, and a lot of bowls.
contraction2Everyone helped clean up and stacked the dishes, as good guests often do.  I left two bowls out on the counter overnight and the next day I drove her to JFK airport in New York from Philadelphia. The next day, when I went to put the bowls away, the bowls were stuck together.  A smaller clear glass bowl was inside a larger blue glass bowl.

I tried prying them apart but with no success.  Then I remembered the phrase I have been telling my daughters for years: “It is brains not brawn.”  What I mean is, when faced with a situation that requires strength, use your brain to figure out the solution if you find yourself not strong enough.   Think pulleys, inclined planes, wheels, the pull of gravity,  (when trying to move heavy objects) and in this case, the fact that matter expands when heated and contracts when cooled (to open jars or release two bowls stuck together).

I used science concepts to free my bowls from their embrace, because pure strength wasn’t useful in this situation.

Here is what I did:

1. Turned the bowls upsidedown in the sink and ran hot water over the blue bowl (it was the outside bowl).

2. Turned the bowls over and immediately filled the clear smaller bowl with ice.

3. Waited a few seconds and was able to pull the two bowls apart.

I think it was the contraction of the clear bowl and the expansion of the blue bowl that did the trick!