Thresholds

Frick Park

Pittsburgh

December 2019

At what point does water freeze?

Most liquids lose volume — they contract — as they get colder.  Not water, at least not some of the time.  Lower the temperature of water and it will contract just like all the others, but only until it reaches 39° Fahrenheit, at which point it will begin to expand, and continue to expand as it gets colder.

This is weird.  Water is weird.  In the lab, scientists have messed around and found a way to keep water liquid down to as cold as 42°F below zero.  Totally weird.

This is what I am thinking while on my walk this morning.  Just before I left the house, I heard the guy on the radio say the temperature is 33°.  Well, because it is raining, this all got my brain churning.

Water begins to crystalize at 39°F, when it expands.  Then, like magic, it turns into ice at 32°.  If the temperature drops just one degree while I’m out here, from 33° to 32°, do we have an analog situation?  Does the water gradually sort of become harder and more rigid?  Or is it digital, as if it clicks over, now liquid, and then in a moment, it is solid.  I kind of need to know;  I’m walking in it.

Let’s follow this a little farther.  I mean, I’m out here, comfortably warm and dry in my waterproof layers, no need to rush off the trail.  Lots of time to think such thoughts.

Water, the liquid, is generally considered to turn into ice, a solid, at 32°F.  We know this, right?  But watch…

Basic physics tells us that water (and most anything) gives up energy when it cools.  After all, temperature is simply a measurement of the amount of energy that is in a substance.  The warmer it is, the more energy it has.  The cooler, the less energy.  (Science is reasonable like that.)


Side trip.  This is mainly for you obstinate Americans who, in 1975, refused to shift over to the metric system.  That is when the United States passed the Metric Conversion Act which called for “voluntary conversion” to the metric system.

Here I will use metric units for my story because it just makes so much more sense.  Justification?  You want justification?  Here’s an example of what it does for us.

Celsius and Fahrenheit are two different temperature measurement scales.  We use Celsius when using metric measure, and Fahrenheit in this other dumb system we’re all used to.  So…

If water cools one degree Celsius, it gives up some energy, specifically one calorie per gram of water. To wit, in the metric system, we measure…

-1° Celsius = -1 calorie of 1 gram H20

We stubborn Americans use the English system, or as we call it, the <Imperial> system.  In the Imperial system, the equivalencies are…

-1.7° Fahrenheit = 0.7377 foot-pounds of 0.035274 ounces H20

Do what you want, but I’m using metric.

Now back to my hike.


Weird water mostly behaves, but when it gets down around freezing, it does some pretty outrageous stuff.  Take water to its liquid state at 0°C (32°F) and convert it to ice, which is to say, remove some of its energy.  How much?  80 calories!  It usually takes 1 calorie and now it takes 80?  And it doesn’t even change its temperature?  This is scandalous!

So when exactly does liquid water convert to solid water?  Woof.  Tough one.


Well, this all got my mind buzzing, thinking about transitions, about thresholds.  At what point do we lose this and gain that?  For now we’re just looking at when exactly water crosses the threshold to ice.

But wait.  I’m still doing my park trek for today.  I’m pondering more thresholds than water to ice.

When we walk in Frick park, Lisa and I often remark about the distant “lonely train whistle.”  Warren Zanes, in a Los Angeles Times article, says, “I’m among those who hear in the train whistle a kind of vernacular poetry.”

Lisa and I occasionally hear that vernacularly poetic train whistle, the one we refer to as the “lonely train whistle.”  It’s been certified lonely by Jimmie Rodgers, dressed in railroad garb, sittin’ on a wooden stool, singing Waiting for a Train and playing on his acoustic six-string.  He yodels.  Just listen;  when he introduces the song, he imitates that lonely train whistle.

As well, our use of the phrase, “lonely train whistle” has been certified by Bob Dylan in Freight Train Blues, where he plays his harmonica and lays out lines like…

The hummin’ of the drivers was my lullaby

And a freight train whistle taught me how to cry.

Dylan turns the word “blues” and the word “shoes” into freight train whistles.  And even though he makes the whistle dance about, it’s still lonely.

Hank Williams actually used the words “I heard that lonesome whistle blow” in his song Lonesome Whistle.  Identified, verified, certified.

When are we first aware of a distant sound, y’know, like a lonely train whistle?  The answer to this question varies depending on whether you are asking Lisa or me.  She will hear it long before I do.  When is it loud enough to cross the threshold of her hearing?  How much louder must it be to cross my threshold, for me to hear it?  And at what point is it lonely?  I guess that lonely train whistle is particularly lonely when neither Lisa or I hear it.


How bad does the pain have to get for it to be time to tell someone?  Where is the threshold?  Where is the dividing line between not feeling well and feeling sick?  Between sadness and heartbreak?

When do we make the decision to continue to climb up the mountain even though our thighs are on fire?  Or do we decide to cut the hike short and go back down, because the fire is not the right kind to power us farther?  One step more?  One mile more?  Or are we done?

At what point do we realize we are in love?

Is it a walk or is it a hike?

When is your last hiccup?  Now?  Now?

When does a hill become a mountain?  My friend Marc once explained to me that for a mountain to be its own mountain, rather than being one mountain with several peaks, it must have at least 200 feet of prominence.  Does that help?

Or how about waterways?  Is it a creek, a river, a stream, a brook or a run?  USGS says there are no official categories.  Now what?


Walking between two trees, I step into another world.  Now there’s a threshold for you.


What is this all about?  Simple.  Be prepared for a walk/hike in 33° weather, especially if the temperature is dropping.

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