A stranger was seated next to a little girl on the airplane when
the stranger 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 shit?