How is a freeze resistant hose bib constructed. How does it work. Relates to outdoor hose bib

Here is an example: lets say that the frost free faucet (that is what they are called in my area) is 12 inches long. The seat and washer that actually stops the water from going through is on one end of the faucet, the handle that you turn is on the other. Therefore when you turn off the water it is cut off 12 inches back into the house. Also these faucets are made so that the spout end will naturally be on the down slope when installed correctly that is so that any water that is in the 12 inch barrel will drain out and there will be nothing in the barrel to freeze. Now one word of caution, any thing left on the faucet, such as a hose or a timer will hinder the drain of the barrel and therefore it can freeze.
I hope you can understand from my description how it works.

LetmetellU just gave you a excellent description of a Frost Free Sillcock, (see image. Let me add to that a little and show you how we addressed this problem in my home state of Wisconsin before Frost Free Sillcocks came out.
We installed Stop and Waste inline valves,(see inage) inside the basement upstream from the outside hose bib. In freezing weather we shut off the valve inside the house and opened up the outside hose bib. We then opened up the small waste outlet on the valve in the basement and drained out the remaining water. A lot of older homes up north still have these installed and use them every winter. Thank you LetmetellU for the dynamite explaintion.
Cheers, Tom