This article is not for beginners, but for those more advanced readers who like to ponder the physics of pool. There is a lot of debate among advanced players regarding the dynamics of spin and deflection. I recommend against thinking about any of the following in a game.
Although squirt and throw have been covered in other articles, we did not include the possibility that, at times, one dynamic can cancel out the other. In other words, either on purpose, which would be extremely difficult, or by accident, which I believe happens frequently, a miss-hit on the object ball caused by a small amount of squirt (side deflection) might not seem like a miss-hit, if the side spin that caused the squirt is precisely enough to throw the object ball back on the correct path to the pocket. (What???)
In the all three diagrams at left (all exaggerated) the shooter intends to shoot the object ball full in the face for a straight-in shot.
(Fig. 1) In the first diagram, a severe miss-hit on the cue ball causes it to "squirt" left, which in turn drives the object ball severely to the right.
(Fig. 2) In the center diagram, a slight hit off center does not cause the cue ball to deflect, but does create throw spin, thus driving the object ball slightly to the left. (I use this shot often for various reasons.)
(Fig. 3) In the last diagram a cue ball hit just enough off center to cause a slight deflection causes the cue ball to hit the object ball slightly to the left of center. However, the spin on the cue ball also throws the object ball slightly left, thereby canceling out the deflection mistake.
A word of caution: Do not think about throw, deflection, or any other anomaly that might take your mind off the game and your focus off the object ball. Many "slumps" are the result of a player trying to introduce techniques into his or her game that should not be artificially imposed. With proper practice, you will automatically make adjustments, and build confidence in your shot making abilities. I just believe it is a good idea to become educated to the existence of anything that might affect a shot.
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