My uncle used to be in the Navy.
He did not know how to talk to a kid.
I asked him to teach me how to whistle.
I wanted to learn how to make that loud
kind of whistling sound that, in theory,
you get with two fingers in your mouth.

In practice, it's quite hard to do.
"What happens when we whistle?"

Let's ask Bob Mcdonald,
host of Quirks and Quarks on
CBC RadioOne, and Dr. Morsink:
http://www.cbc.ca/quirks/