Bowling is one of my favorite activities to do during the winter time. I've tested a lot of different ways to throw, trying to come up with the most effective and consistent way to bowl strikes. I found that hitting the front pin straight on does not work every time because when it hits the front pin right down the middle, the outside pins often wont get touched leaving you with a pretty bad split.
The best thing to do is to hit the front pin but from an angle. What I mean by this is that when the ball comes in contact with the pin, it should strike it from the side of the pin. This causes more pins to fall because when the pin falls at an angle instead of straight back, the bowling ball does not follow the front pin after contact. The front pin will fall to the left causing the left side pins to fall, and the ball will move slightly to the right causing the right side pins to fall. This is due to conservation of momentum.
To accomplish this I put spin on the ball to make it curve into the side of the front pin. At the beginning of the balls path it slides on the hardwood, but after a while the friction of the floor will cause the ball to only move through rotation. If the spin is in the direction that is perpendicular to its original velocity then it will curve inside.