First Test Research

Ball type: Golf ball

Height: 29cm

Surface: Wooden table

I've dropped a golf ball on a wooden table from the height of 29 cm. I have filmed eight different tests of the ball. Each with different force added to the ball, so it moves at different speeds across the screen. I’m going to choose three different videos and study them.

Video 1

Fast ball

The ball moves across the screen pretty fast. It does only two bounces. However, the height of the ball is decreasing with each bounce. Also timing is different with each bounce:

Fall – form the top to the bottom 4 frames.

First bounce – from the bottom to the top 4 frames and from the top to the bottom also 4 frames. But there is one more frame, where the ball holds its position at the top.

Second bounce – from the bottom to the top 2 frames. One frame of hold at the peak and one frame more to get out of the screen.

Total number of frames: 17

The ball is rigid so there is no squash and stretch.

Here is a diagram I’ve drawn to show the curves of how the ball is moving:

Based on this diagram I've created a simple animation of the golf ball following the curve. I'm amazed how this diagram has speeded up my animation. And the timing is right.

Video 2

Medium ball

The ball moves across the screen with a medium speed. Now it does four bounces and the height is also decreasing in similar way as it did in the previous test. Here are the numbers of frames for each bounce:

            Fall – from the top to the bottom 4 frames.

First bounce – from the bottom to the top 3 frames. On the top 1 frame of hold up. From the top to the bottom 4 frames.

Second bounce – from the bottom to the top 2 frames. On the top 1 frame of hold up. From the top to the bottom 3 frames.

Third bounce – from the bottom to the top 1 frame. On the top 1 frame of hold up. From the top to the bottom 2 frames.

Fourth bounce – 1 frame together with the hold up. 2 frames to get out of the screen.

           

            Total number of frames: 25

Here is another diagram to show the curves of this ball:

Here is an animation I’ve done based on the diagram:

Video 3

Slow ball

The ball is moving across the screen slowly. The ball does 8 bounces and continues to roll until it’s out of screen. However, I’ve noticed that the ball is moving so slowly that before it appears on the screen it already has managed to drop from the top to the bottom. So the animation will start from the bottom. Here is number of frames for each bounce:

First bounce: from the bottom to the top 3 frames, 1 frame of the hold up, 4 frames to go down.

Second bounce: 1 frame to go up, 1 frame of the hold up, 2 frames to go down.

Third bounce: 1 frame to go up, 1 frame of the hold up, 2 frames to go down.

Fourth bounce: immediately goes to the 1 frame hold up, 2 frames to go down.

Fifth bounce: 1 frame of the hold up and 1 frame to go down.

Sixth bounce: 1 frame to go up and 1 frame to go down.

Seventh bounce: 1 frame to go up and 1 frame to go down.

Eighth bounce: 1 frame to go up and 1 frame to go down.

Roll: 4 frames.

Total number of frames: 31

Although some bounces take exactly the same number of frames their height changes.

Here is a diagram to show the curves of the ball’s movement:

Based on this diagram, I've created an animtion: