Motion

Lots of things can move:   baseballs, cars, clouds, and people are just a few familiar examples.   When a thing is moving -- that is, the thing is changing its location or position -- we say that the thing is in motion.   Typically, we become aware of and observe an object's motion by noting its movement relative to some other object or reference point.

However, if the object in motion is air, then generally we do not see the air itself in motion, rather we see its effects.  The effects of "air in motion" -- or what we more typically refer to as "wind" -- can be both numerous and varied.  Visually observable effects like leaves moving on a tree or loose papers blowing down a street can serve as the basis for estimating wind speed -- as is the case when using the Beaufort Scale.  Follow this link -- effects of wind -- for more information on this topic.

The physical behavior of objects in motion is described by Newton's Laws of Motion.   The scientific study of the motion of objects is called kinematics.

There are three quantities that we can use to describe an object's motion at any instant.   They are its direction, its speed and its acceleration.   An object's motion can be either constant or accelerated.   With constant motion the direction and speed do not vary (i.e., there is no acceleration).   With accelerated motion either the object's direction of motion is changing or the object's speed of motion is changing or both the object's direction and speed of motion are changing.