Assignment: Bouncing Balls

Contributed by Corrie Francis Parks at UMBC

Learning Outcomes

• Apply the principles of timing and spacing to show changes in speed representing gravity and momentum
• Apply the principles of arcs and squash and stretch to create a believable bounce for different balls
• Base your animation on real-world observations

Preparation

Lecture and reading on bouncing balls is helpful, but real-world observation can be an engaging class activity. If space and time allow, have students bring in different types of balls and observe their bounces in groups of 3-4. They should time the bounces, noting how long each full arc takes, how much height is lost with each bounce, how far the ball travels horizontally, and how it reacts with different surfaces and angles, such as walls, corners, stairs, or different types of floors. Students should attempt to draw the arcs for different balls with their group members as note-taking for the assignment. Video references is also a good idea.

Since this is our students first drawing assignment, I have them animate on paper, for the experience of using light boxes peg boards, and the animation punch. The assignment can, of course, be modified for any digital workflow!

Assignment

Animate two bouncing balls that have significantly different weights or material properties. (e.g. a bowling ball and a golf ball; a beach ball and a bouncy ball). Both balls should bounce in the same environment (i.e. have the same background or structural elements) and interact with at least one environmental element (i.e. off a table, down a step, hit a wall, etc.)

Details:

• Use a field guide so you know where the edge of the frame is. Work at at 16:9 aspect ratio.
• Draw a background on one sheet of paper and use that under every drawing. Both balls should bounce in the SAME environment. You can composite the background with the animation in Premiere.
• Start the bounce off the page and continue it until the ball goes off the page or comes to a complete stop.
• Draw the arcs for each type of ball and mark out the spacing on a separate guide layer.
• When you shoot the drawings, hold on the empty background for one second. Once you have finished, hold again for one second (this makes viewing in critique easier).
• Composite the bounce animation onto the background image. (Tutorial here)

Examples