Culture Shock Continues

I put Israel in the sandbox at Hecksher Playground on Tuesday afternoon, and two minutes later I couldn't find him.  After searching the entire playground (it's a huge place, in Central Park), I finally found him hanging onto a fence by the benches staring at what seemed to be space.  When he didn't answer my calls, I knelt beside him and asked him what he was doing.  Turns out he was fascinated by the sprinklers just outside the playground.

What are they?
They are sprinklers.
What do they do?
They water the grass.
Grass is not for eating.
That's right.  Grass is not for eating.
Will there be strawberries there?
No.  Just grass.
Why is there water there?
The water grows the grass.
But grass is not for eating.
That's right.
Grass is not for eating.
That's right.
Why?
Why don't we eat grass?
Why water?!

He was genuinely confused and concerned.  Water, in Africa, is a precious commodity.  And grass is not for eating.