Jill: Mark is never gonna learn anything if he doesn't do his own work.
Mark: That's right, Dad.
Tim: You stay out of this. This is between your mother and me.
Jill: Tim!
Tim: OK. I'll just watch. I'll guide him. What have you got planned for that solar system?
Mark: Well, the plan was to hang a bunch of Styrofoam balls on wires.
Tim: You can't just hang 'em on wires. First, you gotta get the right proportions for the planets. Then the right distance from the sun - that is perfect, there.
Mark: Dad, I thought you were just gonna watch.
Tim: I am. I'm just tellin' you what I wanna see.