True bias lighting doesn't cause any reflections on the screen, and it only reaches your eyes after first bouncing off the wall — never directly from the source. (digitaltrends.com)
We found it was quite hard to tell by eye alone which ball had bounced the highest as they tended to shoot off in different directions, so for our second attempt we marked a certain hight on the wall, and dropped the balls one at a time from the same height trying to make another mark at the height reached on first bounce. (science-sparks.com)
At first I bounced her while standing and bending my knees, but that soon became very hard on me physically, so I soon discovered the bouncing ball (I use one specifically for babies instead of a yoga ball). (attachmentparenting.org)