Slow in and slow out
Refers to the timing of an object or figure at the beginning or end of a sequence. ‘Slow In’- an action decelerates into a key frame meaning that the object will move slower. ‘Slow Out’- an action accelerates out of a key frame meaning that the object moves faster. Most actions will involve both a slow in and slow out to make the movement of the object look more realistic.
A bouncing ball is the most basic example to represent this principle as it uses both actions, this is called 'Variable Action' it shows acceleration and deceleration within a sequence. A contemporary example of this would be the Pixar Logo animation as both 'Slow In' and 'Slow Out' is used to control the speed of the bounce within the lamp.
Hannah Bentham