It's rotoscoping, you take a photo of the bowling alley, put the ball on it take a photo, then place a small brick under the ball take a photo, then place the 1st picture & the 3rd picture (with the ball raised) using a graphic package like Gimp, you overlay the 3rd photo on top of the 1st & erase the little brick that was raising the ball. so it looks like the ball is floating. you have to do it each time the ball bounces, dozens if not hundreds of frames. V.time consuming