Arcs Link 01 

Arcs Link 02 

Arcs are a very important principle in animation. They are used to give an object life using spline tangents instead of linear. If you have straight in-between frames, then your animation still may seem dead. Therefore, you must implement the use of splined arcs in your animation to breathe some life into them. Gravity and joints have a lot to do with arcs as well, because gravity is always acting. Therefore, everything will have some sort of arcing motion. Also, since we are human and we have joints, our bodies will move with arcing motion, because gravity acts to shift our weight.

Anticipation Research

12 Principle of Animation

   From what I understand Anticipation is pretty self explanatory within animation. Anticipation is when something or someone that is being animated prepares the viewer to see an action. An example would be someone who is going to jump anticipates by bending their knees and getting lower to the ground before jumping up. If you did not have anticipation in an animation it would just feel wrong. You need to have anticipation to make something feel natural and alive.

Research - Pose to Pose & Straight Ahead

Pose To Pose & Straight Ahead

  There are two very different ways to animate. One of the methods is called pose to pose, and what it is directly relates to its name. Pose to pose animation is where the animator would plan out his/her scene prior to starting any animating. They would then set key poses throughout the animation to give them a solid direction. Once these key poses are set, the animator can then go back in and space out and add "in betweens" as needed. These in between frames will be used to glue the key poses together, and ultimately lead to a more fluid animation.
  The other type of animation is Straight Ahead. As with the first method, this one also directly relates to its name. Straight ahead is when an animator creates an initial pose, and then builds off of that. This allows for more creative flow, as the animator is making up all of the poses as they move along. This is best used when you want to have some randomness or wildness to your animation.

Either one of these two methods is fine for animating, it is just up to what your preference may be.

Ease In & Ease Out

Ease In & Ease Out in Animation

  From what I understand after reading this small tutorial ease in and ease out gives your animation more life. What I mean by this is that your animation will seem more lifelike, because nothing ever happens at the same speed at the same time. Usually the action starts slow, speeds up and then slows down again when it is going to come to a stop. 

The example they used is when you are moving your arm up and then moving it down.

When moving it UP it will move fast at first and then slow down at the top.

When moving it DOWN your arm will move slow at first to move out of the up position, and gain speed as it goes down.