Acommon visual behavior is the âhead jerk.â This motion is generally observedwhen an individual otter approaches a raft of sea otters. The approaching otternoses and sniffs the other otters while jerking its head from side to side.
Axis tilt is the vertical angle at which the ball rotates. Axis tilt is what is commonly known as spin. Axis tilt is determined by the position of the thumb during the release. If the hand turns too early, the thumb exits on top of the ball. Bowlers with a high degree of axis tilt will be able to see the top of their hand during the release and follow through.
The Tilt Changes. Earth's axial tilt actually oscillates between 22.1 and 24.5 degrees. The reason for this changing obliquity angle is that Earth's axis also wobbles around itself. This wobble motion is called axial precession, also known as precession of the equinoxes. It is caused by the gravitational force from the Sun, the Moon, and other planets. Acts Like Two Spinning Tops