A few weeks ago, a fair-to-middling snowstorm descended on us, with the weatherman promising 6 to 8 inches of snow overnight. Before dinner, I cajoled Oldest Daughter and Son into helping me shovel the driveway. Then we all came in, but I went out again to shovel the front walk.
At dinner time, my son asked, “Mom, why did you shovel the front walk when it’s just going to snow some more?” I said, “Because I would rather shovel 3 inches now, and then 3 inches in the morning, than shovel 6 inches all at once.”
He replied said, “But that’s twice the amount of work – you have to throw the snow twice over.” My son is all in favor of the Law of Conservation of Energy.
The Common Household Husband (remember that he is a biologist, O Best Beloved), chimed in with some helpful theoretical physics. “As you know, Work equals Mass times Acceleration. So shoveling half the mass of snow requires less work....”
The Common Household Son, who is going to the regional Science Bowl at the end of February, has been studying up on physics, although he has never had any formal class. He could not be fooled, and corrected his Dad's theoretical physics. “DAD, it’s F = ma. That’s FORCE equals mass times acceleration. Force is not the same as Work. Work = Force times Distance.”
His Dad said, “Exactly. Force is related to Work. So half the mass means half the work. That’s half the work today and half the work tomorrow.”
My son objected, “No! It’s twice the work because you have to walk up and down the walk two times instead of one.”
Dad said, “No. It’s the distance you’re throwing the snow, not the distance you’re walking along the way. So the amount of work is the SAME.”
This argument went on for some time. I finally decided that, according to the Law of Conservation of My Sanity, I needed to put an end to the discussion. So I said, “Okay, Son, I’m nominating YOU to go out and shovel the walk tomorrow morning.”
But the next morning, guess who did the Work of moving a Mass of snow a certain Distance? That’s right – me. Because I am the only one around here who knows Applied Physics.
Advanced Applied Physics Equipment