In the car, on the way to theater camp today (Do-Jump, to be specific), she asks more questions about inertia.
Child: “Daddy, if I shake a toy rocket, the little people inside bounce around. How come when the car moves I don’t bounce around?”
Me: “Inertia. Remember when we talked about water in the bottle, how mass is lazy? Things that are moving want to keep moving. Things that are still want to be still. You have more mass than the little people in the toy rocket, so it takes more force to move you.”
Child: “What about in an accident?”
Me: “That’s why we wear seatbelts.”