The Why Game: Isaac v. PhD Mom

We all remember the Why Game, right?  Isaac has started.  We'd say something and he'd ask why.  Then he'd as why to the answer, and to the next, and so on.  Well, players of the Why Game, you have met your match--Bianca, or Professor Sculimbrene to kids at Holy Cross. 

We were driving home from a good nature hike (Mass Audubon's Flat Rock Sanctuary) when the following conversation occurred:

Us: Time to go.
Isaac: Why?
Us: Its lunch time.
Isaac: Why?
Us: Well, we are hungry.
Isaac: Why?
Us: Because we just went on a big hike and we need food.
Isaac: Why?
Us: Because we need food to replenish all of the energy we spent on the hike.
Isaac: Why?
Us: Well, food is how our bodies make energy and when we spend energy we need to get more.
Isaac: Why?
Us: Because our bodies can't just make energy.
Isaac: Why?
Bianca aka PhD Mom: Energy cannot be created nor destroyed, according to the First Law of Thermodynamics.

Bianca won this round of the Why Game.