And his parents were glad for the time away from baby-care duty. It was all too innocent, I realize now. So time with Clark was just as new for me as it was for him. The problem was that I forgot to turn off my analytical engineering mind when I was with him. And that's when it slowly hit me.
Babies clearly violate Newton's Law of the Conservation of Mass.
I further noticed how Clark would flail his arms and legs about like a perpetual motion machine, and that got me thinking even more. After estimating the mass of his arms and legs and then carefully measuring the distance of motion and the timing of his movements, I calculated how much kinetic energy he expended within a 24-hour period. On the contrary, for every kilojoule a baby consumes, it expends at least four or five kilojoules of energy. It all became abundantly clear when I thought again about Newton's life. Even though he was the father of physics, in real life he was nobody's father.