Saturday, April 20, 2013

Of course all of the sunflower seeds are at the top of the feeder


I am a particle scientist.  Not in the muon, neutrino way but in the everything solid is made up of smaller parts, or particles way, much much larger than a quark.  I studied the shape of individual particles to determine things like flowability (how do you get all the jello mix out of the package) compaction (how do you get a tablet of ibuprophen to stay together) and coverage (how does that black paint look so black).  I used techniques to study these particles individually and in bulk.  It was an early lesson that the whole behaved differently than the sum of the parts.  One of the very first experiments to demonstrate this was entitled “why are the brazil nuts always on top” back in like 1962 I think.    Counter to all of our intuition, the largest pieces rise to the top of the can of mixed nuts.  If I examine this nut, individually it is large, it is dense and it is long.  If I put it on a bed of smaller peanuts I would expect it to sink down into the bed because it has so much mass in comparison.  In fact, the brazil nut will always rise to the top, no matter it’s mass.  It’s shape creates a packing density difference.  These long banana shaped nuts do not stack well, there is room around them for smaller nuts to maneuver.  So all of the small nuts, in their search for lowest energy state, seek to fill in the gaps and move lower in the can.  Add a little vibration and well, you can use this trick to get the biggest pieces of popcorn to the top of the bag. 
Alone, they are just nuts, together they are examples of granular convection.   The best part- we are not exactly sure why this happens. I gave some of the reasoning but there isn’t an agreed upon comprehensive explanation. 
Today I remember my curiosity counselor Dr. Brian Kaye.  He made chaos exciting and opened my mind to accept quantum mechanics.  He was a major influence in the lives of many women, taking them on and encouraging them to get graduate science degrees.  He sought to make the mysteries of science accessible to everyone, writing books on complicated topics in simple language.  He loved language and studied etymology, his books filled with side-bars on word origins.  He strong armed the university into letting all of his ‘harem’ (seriously, that’s what some of the other old farts used to say) attend, participate and lead industry workshops giving us real world experience.  I oft retell the story of leading my first workshop at the Powder & Bulk show and how there were no stairs to the stage.  I, in my pretty skirt suit, had to go around back and climb up on- I was the only woman speaker in the entire conference proceedings.  Dr. Kaye told my parents once that my gift is my ability to explain complicated things in an easy to understand way.   I know he helped me cultivate that gift, one I use every day in every way.  I love to share knowledge, like why we think the sunflower seeds are at the top of the feeder.  

No comments:

Post a Comment