Newton's first law on a rafting trip

 Yesterday, my family and I took a rafting trip down the Colorado River.  

The trip began with the obligatory safety and instructional lecture.  Dylan the perky guide assured us in an enthusiastic voice that we were about to have FUNNNN!  And then when we didn't holler in ecstasy, he asked us again if we were about to have FUNNNN!  Thank goodness the parents with two enthusiastic ten year olds in tow gave the requisite response so that Dylan moved on.

In a spiel that reminded me of the boat operators on Disney's Jungle Cruise, Dylan went on to explain truly important safety information like what to do if you fall out of the raft, how not to accidentally whack your seatmate with an oar, and so on.  Next came navigational instructions.  After demonstrating proper paddling technique, he described the commands we might hear.

"When I say 'forward one', everyone paddles one stroke - only one stroke! - forward.  Everyone show me 'forward one'!"  Everyone dutifully mimed a single stroke.

"Now show me what you do when I say 'backward one'!"  The assembled masses pretended to paddle backward once.

"Sometimes I'll have you paddle 'full forward'!  What do you think that means?" Some shouts from the ten year olds suggesting that we should keep paddling forward.  "Good!"

"And finally, if I say "all stop," then hold on to your paddle, but keep it out of the water.  What do you think happens to the boat?"

My moment had arrived!  "The boat continues to move at a constant speed, due to Newton's first law!" I said loudly enough to get a Look from the fellow rafters, including, especially, from my own family members.  Dylan looked a bit hurt that I had anticipated his punchline.  But, he cheered up a wee bit when the ten year olds shouted that the boat would stop.  "No, the boat is on a river, it's gonna keep going! Dylan cheerily told everyone, while he looked sidelong at me.  Sometimes it's a social curse to know physics.  

Tune in next episode when I describe how I explained the phenomenon of concave acoustic mirrors to a flummoxed guide on our Savannah, Georgia Ghost Tour.