A lesson on falling and acceleration (+inertia)
This is an introductory lesson to falling and g, but with an aside on inertia. I used two tennis balls, 1 secretly weighted with water, and dropped them from a height to introduce, then I got a student to roll them along the floor with equal force to show inertia. There are two cool puzzles, one for inertia and one for the rate of falling, both space based. The lesson provides simplistic data on speed vs time of falling tennis balls for graph plotting and gradient calculation.