Keyframing a bouncing ball in After Effects can be challenging but is surprisingly easy once you understand how the easing curves in the graph editor must look like. A bouncing ball is accelerated by gravity and gravity is a constant force. Therefore, the speed graph must consist of only straight lines (going upwards while the ball falls down and accelerates and going down while the ball flies upwards and slows down). That means easing your keyframes is super easy and involves no guesswork at all: Just open the speed graph in the graph editor and adjust all keyframes such that the speed graph consists of only straight lines!