My father dealth a little bit with energy and used the term after I got a little bit of the idea about it. What he would have done I know, because he did in fact essentially the same thing--though not the same example of the toy dog. He would say, "It moves because the sun is shining," if he wanted to give the same lesson. I would say "No. What has that to do with the sun shining? It moved because you wound up the springs."

"And why, my friend, are you able to move to wind up this spring?"

"I eat."

"What, my friend, do you eat?"

"I eat plants."

"And how do they grow?"

"They grow because the sun is shining."

And it is the same with the dog. What about gasoline? Accumulated energy of the sun which is captured by plants and preserved in the ground. Other examples all end with the sun. And so the same idea about the world that our textbook is driving at is phrased in a very exciting way. All the things that we see that are moving are moving because the sun is shining. It does explain the relationship of one source of energy to another, and it can be denied by the child. He could say, "I don't think it is on account of the sun shining," and you can start a discussion. So there is a difference. (Later I could challenge him with the tides, and what makes the earth turn, and have my hand on mystery again.)

A game Feynman's father would play with him, asking what made things work, and following the chain of energy back to the sun.

The moth moves across the porch, millimeter by millimeter, a brief stage of a longer journey of energy from the core of the sun to the table of the ants. Protons fuse at the center of the sun, releasing energy. The energy diffuses upward, taking several million years to reach the sun's surface, where it is released as heat and light. The light streaks across ninety-three million miles of space, reaching the Earth eight minutes later, where it falls upon the green leaves of plants. The plants store the energy as carbohydrates. A moth stops at a flower of a plant and sips the sugary nectar. It uses the nectar's stored energy for flight. reproduction, and building a body rich with organic compounds. The moth beats its brains out against my porch light and falls dead to the floor, where it is discovered by a scout of a colony of ants. The call is raised: "Food! " Now the rest of the colony arrives, at first in ones and twos, then en masse. A storm of purpose ignites their tiny brains. Humping their backs and fiddling their legs, they have a go at the moth. The moth drifts across the porch floor, taking the packaged energy longer to cross a few feet of painted boards than it took to travel from sun to Earth.

From the sun to the ants that eat it.