Before each serve, most professional tennis players go through a ritual to get in the zone. Novak Djokovic will bounce the ball with his racket, then with his hand. Rafael Nadal will usually pull at his shorts and the sleeves around his shoulders, then touch his nose and tuck his hair behind his ears. Each has a very distinctive routine. But there’s one tennis ritual nearly every pro tennis player does: choosing a specific tennis ball. A common belief among players is that the ball they choose can help them win.
But there’s real physics at play behind this ritual — and It all comes down to the fuzz. For a faster serve, players try to find a compact ball. For a slower serve, they feel for more fuzz. The idea is that a fluffier ball is more likely to be slowed by drag as it travels through the air — and that choosing the right level of fuzz can help the serving player defeat their opponent.