Opie didn’t really throw the rock into the lake Sir Ron Howard, who played the character of Opie, Andy’s son on the show was 6 years old at the time of filming the scene which required him to throw the rock into the lake. However, he wasn’t strong enough to throw the rock far into the lake, so the assistant director of the show had a man hidden behind the bush to throw the rock. You can find a subtle lag in the actual throw and the resulting splash, if you watch the show