Thursday, 11 August 2016

Ducks and Drakes

It is 1957. Two young boys are playing barefooted among the river stones. After three hours they show no sign of being bored. They have built dams and lagoons and constructed highways for Dinky cars. Now they are playing the game that their father calls "Ducks and Drakes," although they mostly call it "skiffing".
Jim and Alex Stevenson, circa 1957 
They are brothers. The older one has the advantage of strength, but the younger one has more finesse. He spends more time looking for just the right stone. It has to be flat on both sides and it has to sit warmly in the palm of his hand. By now they have played for so long that most of the flat stones that were on the shore are in the middle of the river where they shine on the flat, smooth, dark slab of stream-bed like coins in a wishing well. The remaining stones on the bank are less than perfect; too big, too small, too spherical or only flat on one side.

The jumble of river rocks on the bank changes with every flood but there is always a little beach at this spot. The strong current is funneled through a solid limestone chute that the river has carved out of the bed-rock. The main flow is near the far bank while the near-side is calm as a mill pond. In fact, the current is reversed along the beach, drifting up-river to rejoin the rapids that drop into the chute.  When the river is in full spate there is a whirpool here that audibly swirls, sucks and gurgles above the rushing white-noise of water and the strange submarine bonks and bumps of boulders on the move.

Fast water like that can transport rocks, gravel and sand, but as soon as it loses it's energy it drops its burden; the heaviest stones first, then the grit and pebbles and finally fine grains of sand. The sand lies nearest the water and the rocks get bigger as you ascend the beach, placed there during the heaviest of floods. The best skiffing stones lie in a strand line, above the sand and below the boulders, but now they are all gone, so the boys keep looking between the bigger rocks where they find a few more to send skipping over the water.

The brothers are both expert skiffers, having spent countless summer afternoons playing this game that members of their family have played here, in the same spot, for almost a century. They bend low and launch their missiles at a shallow trajectory so that they hit the surface flat and fast, like a seaplane landing at high speed and bouncing back into the air.

Boys like these two have probably been skiffing, skimming or skipping stones since the Stone Age. It may be the World's oldest sport, a precursor of cricket and baseball from the times before we invented the wheel or filled a pig's bladder with air to make a ball. Now there is an official world record for the game.*

The young one curls his index finger round the outside of his stone to send it in a flat spin so that, even though his brother's stones go further, he always makes his jump more times. Because of the spin, his stones travel in an arc, not a straight line. With each skip, forward momentum decreases, the spin takes over and the curve becomes tighter. That curving arc of splashes, getting closer and closer together is a thing of absolute beauty and mystery to behold, like a shooting star.

The science of it, both the skip and the arc, has been studied by physicists and the mathematics involved in describing it may even have made possible our space-age efforts to land a man on the moon or put a robot on a comet.

As for those two boys, who knows what their future holds? What forces will shape the arc of their trajectory?

*The Guinness Book of Records reports that the record was achieved on September 6, 2013 in Pennsylvania by Kurt "Mountain Man" Steiner, age 48. The record stands at 88 skips.

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