The Essentials- Hypothesis: Slippery Conditions

We hosted our first official broomball tournament today and it was great.  Nine teams of two battled on a 600 square foot sheet of ice in a north Minneapolis backyard.  It was a great turnout and a great time but once again I was most intrigued by the ice.

At 8:00am this morning the temperature was perfect for a quick shovel and last minute flood.  After glazing the ice with a thin layer of hot water (hot water promotes good integration of the new water with the existing substrate and also freezes faster(yet another topic for another time)), the sheet was silky smooth.  I was impressed with how the flood turned out and I wasn’t sure if the ice could get any smoother than after the morning flood had frozen. I was wrong.

By the end of the day the ice was much slicker. After thinking about it I have a hypothesis to explain my observation.  All day long the ice was subjected to dozens of feet, scrubbing tiny crystals against the surface, buffing it to a brilliant polish.  The crystals were provided by the snow that has recently fallen and that snow was transported back onto the rink by every player’s feet.  I don’t know if this is what really happened but it makes for a compelling story.  The story is only part of a hypothesis because in science a hypothesis has to have standards.

This explanation works as a hypothesis because it is testable.  That is to say that I could re-flood the rink to mimic the pre-tournament conditions, measure the slipperiness, treat the ice with a good snow assisted boot scrubbing, measure the slipperiness again and compare the results with the first test.  Based on the results of my little experiment my hypothesis would either be supported (not proved) or rejected.  The hypothesis has the power to eliminate possibilities but never prove an explanation because science always leaves room for better and more conclusive evidence to trump previous assumptions.

This rink test is a simple example of experimentation and represents one way of how science works to understand the natural world. Science isn’t, however, limited to experimentation as a way of knowing. Experimentation is just one of many tools science carries on its utility belt of knowing.  Unfortunately those means, and their explanations, will have to wait for another day to be resolved.

This is What I've Been Waiting For (Part 3)

Wonder of Water Miracle of Molecules
Water is a polar molecule which means that it has both positive and negatively charged ends.  Like the poles of a magnet the poles of a water molecule are attracted to each other.  These polar attractions are called hydrogen bonds. In its liquid state water molecules form and break hydrogen bonds at breakneck speeds.  It is the coupling and uncoupling of molecules that allows liquid water to both stick together and flow.

As the energy economy of water moves toward recession (the molecules get colder) the molecules become increasingly thrifty with their motion.  Just as a frugal investor might favor stable government issued bonds to avoid the risks of a down market, water molecules hedge their more fluid hydrogen bonds for steady hydrogen bonds entropicly issued by their crystalline structure.  

So what does this have to do with the rink? The rink survived because of one of waters properties that comes partnered with its polarity, specifically, its specific heat. Specific heat is the amount of energy a substance can absorb before changing its temperature and water has one of the highest specific heat values of any substance and its resistance to changing temperature is even greater when frozen. 

In anthropomorphic terms Ice is more willing to organize itself into a solid than it is to regain the increased freedom its molecules would enjoy as a liquid.  In a down energy economy the frozen water molecules are hesitant to liquidate their assets.

And so the rink survives due to the miracle that is water.

There was also a nice mini miracle in the form of a late New Years Eve rain/snow storm followed by a two day respite from the tropical winter. January started with temperatures in the teens and the accumulated snow made for nice patch material to fill the accumulated holes in the rink.  Over those two days I carefully but aggressively flooded the rink and gained several centimeters of ice.

The temporary relief from rising temperatures (we were back in the fourties again today) along with my renewed confidence in the forgiving properties of my favorite polar molecule was what I was waiting for and has helped me enjoy a happy new year.

This is What I've Been Waiting For (Part 2)

Dying a Slow Death (or Undesirable State Change)

For the last three years I have built a hockey rink in my back yard.  This season I managed to build a pretty good base of ice in the first week of December but needless to say the sheet was threatened by the onslaught of thermodynamic energy that consumed the bulk of the month.

Every day the thermometer ventured above the melting point my once beautifully bound water molecules absorbed the ambient energy and their once indiscernible frozen vibrational motion transitioned to the all too perceptible flow characteristic of a liquid.  The water found its way out of the rink, marched onto the sidewalk and onward toward the requiem of a rink.

My youngest son’s birthday is at the end of December and when asked what he wanted he didn’t list toys or video games but said he wanted to skate with his friends. Leading up to the party daytime temperatures were consistently above freezing. My worry grew as the moderate temperatures threatened the realization of my son’s modest request.  I nursed the ice through its winter fever with late night infusions of water but it lost more than it gained and by the day of the party the corrosive heat had carved a pair of full depth holes in the deck of ice.

On the bright (literally very bright) side of things the kids had a blast spending hours and hours playing boot hockey in shirts and hoodies under a sunny sky and 40 degree temperatures. After a great day the rinks holes had grown, I sprayed off the coating of dirt that was transferred from the snowless yard and I considered the possibility that the first and last ice event of the season had come and gone.