A stranger was seated next to a little girl on the aeroplane when he turned to her and said,

"Let’s talk. I’ve heard that flights go quicker if you strike up a conversation with your fellow passenger."

The little girl, who had just opened her book, closed it slowly and said to the stranger,

"What would you like to talk about?"

"Oh, I don’t know," said the stranger. "How about nuclear power?" and he smiles.

"OK" she said, "That could be an interesting topic. But let me ask you a question first. A horse, a cow, and a deer all eat the same stuff - grass. Yet a deer excretes little pellets, while a cow turns out a flat patty, and a horse produces clumps of dried grass. Why do you suppose that is?"

The stranger, visibly surprised by the little girl’s intelligence, thinks about it and says,

"Hmmm, I have no idea."

To which the little girl replies,

"Do you really feel qualified to discuss nuclear power when you don’t know shi*?"