wiki Word: Weather Cocking

Definition: The action of a weather vane's action.  The action of a weather vane is pivoting about the vertical bar and always pointing into the wind.

Following a model rocket's lif-off, it tends to pont into the wind's direction.  This is also known as the term weather cocking, which is actually caused by aerodynamic forces.  Weather cocking is the action of a weather vane.  (See picture below...) 

Notice how in the black sketch at the top of the overall image has wind with an arrow.  The arrow is pointing to the weather vane, which is currently weather cocking because it's pointing torwards the wind.  If the rocket sketch were on the ground and not in the air, there wouldn't be any weather cocking going on.  Instead, there would just be a weather vane without any action.

In our water bottle rocket lab, we didn't actually have a weather vane, but the top of our water bottle rockets did show the action of a weather vane, or weather cocking, by pointing in the direction of the wind in the project.  When the water rocket bottles shot off, the end where the cap used to be is pointing downward, which is the direction of the wind flow in this case.

I found the information for weather cocking from:  Benson, Tom. "Weather Cocking." 17 Nov 2005 12 Feb 2008 <http://exploration.grc.nasa.gov/education/rocket/rktcock.html>.

I got the picture from the same page...