Field Notes

As I traveled home on the commuter train tonight I had an Einstein moment.  No, I didn’t solve the grand unification theory.   Much to my and all the passengers dismay, the A/C was broken on the train.  It was 90+ degrees today so needless to say the train was a bit uncomfortable.  However, unlike the great majority of the passengers who choose to be miserable, I set out to make the best of it by reading David Levy’s The Sky.  As we traveled the 1+ hour path from Washington DC to Fredericksburg, VA I noticed something odd, there was an occasional breeze.  I thought, hmm, they must have opened the doors to get some air moving, but they had not.  Again, at each stop I noticed the breeze.  Then, BOOM!  I thought ah, physics.  I realized that we were in a closed system.  I was connected to the train via my seat.  The air around me was not.  As the train traveled and began its breaking process, I and the train shared the same negative acceleration.  (Yes, I realize there is a slight difference as my connection to the train is based on the friction and gravity holding me to my seat but the difference is negligible.)  So back to our story.  As we slowed the air around us was continuing at its constant speed until it collided with the wall of the train.  Now, I am sure there is a fluid dynamics problem in this for the turbidity of the air but long story short a breeze.  I would time leaning out of my seat at each stop to feel the pleasant cooling breeze because I stopped to think about the world around me.  It is so much fun to connect with the natural world around you.

This experience reminded me of the presentation by Neil deGrasse Tyson I attended 2 weeks ago.  He stressed the importance of understanding physics and science because it impacts our understanding of the world around us.

As I got off the train I phoned my wife and described the scenario ending the conversation with, “When I get home, tell me if you determine why I felt a breeze.”  She’s smart.  She got it.  The fun part was explaining it to our 8 year old, who also figured it out with minimal assistance.  We then took the opportunity to relate it to Einstein and Special Relativity which describes that all uniform motion is relative to an observers state of motion.  I thought that I must save this example for the next EPO or lecture I do.

GOD I LOVE PHYSICS!