Timing and Spacing/Slow in and slow out

Timing is very important, in an animation, if the timing in a scene is wrong the whole scene will be wrong, let's have a look at a bouncing plasticine ball where I have made a mistake in the timing.

(And spacing makes an animation more fluent and more realistic).

In this animation you can see that there is a mistake in the timing between two frames, when after hitting the ground the ball heads towards the sky, there is a missing frame in-between (The extra frame should have been closer to the previous frame, so there is also a mistake in the spacing, since the next frame is too far 4rm the previous one).

Missing frame- this is where slow in and slow out are useful

To make an animation look more realistic, (An animation with a beginning and end point- like for instance someone starting a run and coming to a stop or someone standing up or even a thrown bouncing ball, or something falling from the sky) there should always be more frames at the beginning and at the end of the animation, in the middle there should less frames than in the beginning and the end. If you look at my video, there is a mistake in the timing and spacing, when the ball flies off the ground, there should have been more frames, then later less, but there is a missing frame so that the slowing out looks wrong a bit.