Frustrations of teaching physics to a 4-year old

Not that I'll ever get tired of pushing her (well, alright, that's not completely true...) but it would be nice if our daughter would learn that she could propel herself on the swingset so she doesn't have to constantly rely on Daddy. I've tried explaining this* to our daughter, but she doesn't quite grasp that "torque, applied mostly at the ends of the oscillation, will add energy just like a push." She's also seen her friends and I demonstrate proper swinging technique, but it's all been to no avail so far.

Oh, well. At least I get the pleasure of watching her smile and giggle with glee with each push I give her. Hmmm... maybe I shouldn't rush things.

*link via GeekPress