Fluid Dynamics

1 June is Children's Day in Poland.  If the date falls on a school day, as it was this year, kids in school generally go on outings.  Teachers don't expect homework.  And lots of parents give their children gifts or treats.  Kids not yet in school also get some sort of gift or treat for the day.  Fortunately, Hallmark has not yet reduced it to card giving -- it feels like a genuine sort of holiday, though its origin is not clear to me.

Maus's tricycle recently broke -- it was just 2 months old and came from a reputable shop, so of course we took it back and complained, and of course at the moment of complaint the shop reverted to communist mode of thinking and stared at us in disbelief and then asked us to fill in a questionnaire and then told us to wait two weeks for an 'adjudication.‘  How’s that for customer service, eh?  We’d thought of replacing it, or possibly of upgrading to one of the very small bikes that are made for young kids these days.  Fortunately, I surfed the web a bit first.  One website that seemed to know what it was talking about advised against bicycles before age 3 or even 4.  The argument being that younger children haven't developed sufficient balance, strength or coordination.  My observations of Chris jibe with that.  He trips over himself pretty easily, and ability to concentrate (even on remaining upright) is limited.  So we'll revisit the bike topic again next spring.  In the meantime, we faced a gift-gap.

We want to encourage him to run around and simply play with as few constraints of preconceptions as possible.  So I bought him what in Poland is called a handball (though it is nothing like the handball I remember from New York).  In Poland a handball is a half-sized soccer ball, made with the same sort of materials and patchwork of hexagonal pieces as a traditional soccer ball.  Rolling it, kicking it, throwing it would all be good for the little guy's coordination, strength and balance, I figured --  and in the meantime, we could have a lot of fun together, rather than the frustration predicted for giving a bike to a child unready for it.

So I bought the ball, and it has been a great hit.  We take it to the park and the playground and play together.  Other kids sometimes join in.  Primrose plays with us too for a while, then wanders off, nose to the ground.

  

But all this, which is once again true, was interrupted for a few days, about ten days ago.

One day, after we had played with the ball in the park, we went down to the river, Chris proudly carrying his ball in both hands, refusing to give it up.  He now understands that he is not supposed to go closer to the water than about two metres unless he is holding my hand.  And he’s quite good about it.  What he did not understand, it seems, is that heaving his ball into a flowing river might cause some problems.

"Heaving his ball" must be understood in context.  Chris is 26 months old.  Throwing his ball with all his might will, 90% of the time, result in it going about one and a half metres.  He still throws underhand, and the ball is large enough and just heavy enough that throwing it requires both hands and all his strength.  But this time he really heaved it -- achieving a long lob o at least four meters, a personal best (to date).  It plopped down in the slow moving river just a little beyond the range at which I would automatically have waded in to get it.  I have waded into the Warta before, and I know that the most likely things to be found beneath it's surface are beer bottles, thousands of them, many of them broken.  There are also all sorts of rusting detritus that can pierce human flesh with ease.  I was wearing rather nice shoes.  It was clearly a case of sacrificing my shoes, or myself -- or a $10 half-sized soccer ball.  After a moment's thought, I decided against both contracting tetanus (or worse) and ruining my shoes.

In defence of my choice, which made me feel cowardly and unfatherly, I assumed the ball would soon drift to the river's edge, so why bother with ruined shoes and wet trousers, let alone ambulances, amputation and life in a wheelchair?  But the damned thing stubbornly stayed near the centre of the river beyond reach, mocking all my assumptions about what happens to the stuff that is thrown into a river.  Somehow, I thought it all either sank or drifted to the edges.  If not, why not?  But far from drifting closer to the edge, where it would have got stuck into the reeds and grasses and have been easily retrievable, the ball stubbornly drifted more toward the centre of the river, where the current was strongest.

This made no sense to me; it still makes no sense to me.  (if you know the answer, please tell me.)  I was sure the ball's motion would exhibit the effects of some sort of drag factor and get pushed out of the main current toward the slower moving water at the sides.  But it didn't happen that way.  Chris watched it all very closely.  His eventual understanding of fluid dynamics, when he evolves one, is almost certain to be better than mine.  Unless one is a scientist, these sorts of things are intuitive -- such as the idea that an iron ball must fall faster than a feather -- and it takes something very special and very strong to dislodge the results of childhood conclusions and replace them with observed facts.

There was still another possibility for rescuing the ball.  Primrose. "Get the ball, girl!"   To my gob-smacked amazement, she jumped right into the river and paddled madly, getting to the ball in no time.  A regular Lassie.  She likes water, but not swimming.  She rarely goes beyond the depth at which her paws are touching something (in the Warta, most likely broken bottles).  I had never before seen her swim nearly to the centre of the river, and I didn't expect her to do so this time.  But she performed brilliantly,  heroically.  But then she made her only mistake.  She tried to get the ball into her mouth.  But her mouth was just a bit too small for the task.  She might have herded the ball, but she is not a herder.  She is a hunter, a retriever (actually a type of pointer).  Trying with everything she had, she succeeded only in pushing the ball farther away -- and in making me worry if she weren't going to drown in the process.  A lost ball would have been nothing compared to a lost Primrose.  Eventually, weary and embarrassed, Primrose returned to shore.  Maus and I cheered her wildly, but we still didn't have the ball.  Primrose accepted our applause, but one could see that she thought she ought to have done better.

The river, and therefore the ball, were not moving very fast even at the centre of the current.  It was easy to walk faster than the flow.  I remained convinced that the central current of the river would push the ball toward either of the sides and eventually cause it to catch in the intermittent shrubs, reeds and grasses that grow along the river's edge.  (Einstein, speaking of science, said that the definition of insanity is doing the same thing and expecting different results.  This applies also in everyday life, though it happens quite often.  Being certain of something does not make it so.)

We had Chris's stroller with us, but using it along the river’s edge is not that easy, even though there is a path most of the way.  Hoping the presence of two sunbathing girls lying on the nearby grass would dissuade any thieves that might have contemplated snatching the stroller, I left it in situ and put Chris up on my shoulders.  This is currently his favourite position for watching the world, and he is remarkably observant.  We set off loping along the river bank, hoping our little ball would tire of the game it was making us play and come close enough for me to grab it without too much commotion.

In fact, the ball exhibited several of Chris's own characteristics of the moment.  Obstinacy, teasing  playfulness, deafness to my imploring voice, disdain for instructions, a certain slyness, a propensity for mischief.  All the ball lacked were a radiant smile, twinkling eyes, and a pure, silvery, high-pitched squeal of delight.

With Primrose alternately tagging along and running ahead, we went down the western side of the river for half a kilometre, to the point where the ball had to decide (yes, I know I am anthropomorphising a half-sized $10 soccer ball) which channel of the river it would take around Cathedral Island (Ostrów Tumski).  Had it chosen the other one, it would have encountered patches of bog that surely would have stopped its progress, though they would also have made retrieving the little thing a royal muddy mess.  But, being a clever blighter, it feinted toward the boggier channel and then swung back into the faster flowing, wider channel.  So, with Chris on my shoulders, we attempted to get to the other side before we lost sight of the ball.  We headed to the Cathedral Island Bridge and crossed over to Cathedral Island itself.  As so often in spring and summer, the island was crowded with tour buses of nuns, priests, and brain-washed school children -- including, I noticed, a large contingent of buses from France, where they have far more interesting (and authentic) Gothic cathedrals than one will find in most of Poland.

Chris and I got down to the bank of the river just in time to see our little ball alter course away from the shore and back toward the centre of the river.  Now I was sure the Gremlins were in charge.  I had to laugh.  How did it do that?

I was also thinking, "Where's the silver lining in all this?"  I see everything I do with my son as an educational experience for both of us.  Either I am teaching him something, or he is teaching me something, or the Gremlins are teaching us both something.  Or Primrose is teaching us all something.  Most often it's a combination of these things.  I wondered as we walked, What's the best lesson in this for wee Master Maus?  I wasn't sure.  I still felt bad for not having jumped in to save the day at the start -- even though doing so would have been dangerously stupid.  Definitely not the right lesson to teach. There is such a thing as overdoing it, and I don't want Chris to overdo everything in life, working himself into a lather over small things, rendering himself too tired or frustrated for the big things.  Proportion is something I lack totally, but I don't want Chris to suffer from that condition.  It makes for a tough life.  However, I also don't want my little guy to quit too easily or to get the idea that half-sized soccer balls are infinitely conjurable with the flash of a credit card.

We kept on for a while, tracking along the shore, watching the little ball as its short playfully lyric voyage became a sort of epic.  At the far end of Cathedral Island, where the tracks to the little Poznań-Garbary railway station cross over the river on a very rusty and shabby looking railway bridge, the river ceases to have a passable bank.  Shrubs, reeds, mud and all sorts of rubbish block the way.  Neither I (with Chris perched in his observation post) nor Primrose could continue, though Primrose made it a bit farther than Chris and I.  Unable to continue, we waved goodbye (in Polish one waves pa pa) to our errant little ball and wished it an exciting journey.  That is, Chris and I wished it well.  Primrose was still a bit miffed at having been bested by a $10 half-sized soccer ball.

We rather wearily walked back over the Cathedral Island Bridge and along the grassy bank to the Saint Roch bridge, about two kilometers, perhaps a little more.  I walked and Chris rode.  Of course, I babbled on about all the fun the little ball would have, and all the things and places it would pass on its way to wherever it was going.  I mentioned that it might even make it out into the Atlantic Ocean if it kept up as it was, and perhaps go all the way around the world.  Mistakenly, I said it might go to Gdansk (I should have said Szeczen).  Or it might stop someplace along the way and be found by another little boy or girl who didn't have a ball.  I'm sure this is the usual happy-talk one says to children in such circumstances -- and I don’t advocate altering the tradition.  However, I expect Chris, even at 26 months, was already hoping I'd get something stuck in my throat.  Really, dad, it was only a ball.  But thanks for trying to get it back for me.  That was pretty cool, dad.  We had fun, didn't we?  Yes, Maus, we definitely had fun -- I expect I will remember it all the days of my life.  I hope so.

After a few days of mild grumpiness about the lost $10, I went back to the shop to buy another ball -- only to find that the sale during which I had bought the previous ball had ended, and the price had increased by 25%.  Damned Gremlins -- clearly in cahoots with the little ball and the retailers. They probably got a cut. Sometimes the only appropriate this to say is Welcome to Poland.