Why
Does the Air Speed Up?
When moving air encounters an obstacle--a person, a tree,
a wing--its path narrows as it flows around the object. Even so, the amount of
air moving past any section of the path must be the same, because mass can be
neither created nor destroyed. The air must speed up where the path narrows, in
order to have the same mass flowing through it. So air speeds up where its path
narrows and slows down where it widens.
(Rev. 08/31/99)
