Suppose you deflate a bicycle tire by depressing the air valve. ...

[Bernana]

Suppose you deflate a bicycle tire by depressing the air valve. Why does air rush out of the tire? After the air stops rushing out of the tire, is the tire empty? Explain your answer.
  What will be the ideal response?

Question 2

The atmospheric layer that is influenced by friction is called the friction layer or the ___________________ _ layer.
  Fill in the blank with correct word.

[dudman123]

Answer to Question 1

ANSWER: The air pressure in the bicycle tire is higher than in the surrounding surface air, which creates a difference in pressure. The pressure difference establishes a force (called the pressure gradient force) that causes the air to move from higher pressure toward lower pressure. Consequently, if we remove the air valve on the tire, air is going to flow out the tire until the same pressure exists inside the tire as outside the tire. The tire will not deflate entirely, only as long as there is a pressure gradient.

Answer to Question 2

ANSWER: planetary boundary