Summary: David Alciatore, PhD ("Dr. Dave") ILLUSTRATED PRINCIPLES
"Squirt Part VIII: squerve effects"
Note: Supporting narrated video (NV) demonstrations, high-speed video (HSV) clips, and
technical proofs (TP), and all of my past articles, can be accessed and viewed online at
billiards.colostate.edu. The reference numbers used in the article help you locate the
resources on the website. If you have a slow or inconvenient Internet connection, you
might want to view the resources from a CD-ROM or DVD. See the website for details.
This is the eighth and final article in my series dealing with "squirt." So far, we have looked at
basic terminology, the physics behind squirt, some experimental results, the effects of follow and
draw on squirt and swerve, techniques for compensating one's aim for squirt, low-squirt cues, tip
shape effects, and cue-test machine results. To refresh your memory, squirt, also called
deflection, refers to the angular change in the initial cue ball (CB) direction due to an off-center
hit. In other words, when you use English, the CB doesn't go where you are aiming because of
squirt. For more background information, see my August '07 article and refer to NV 4.13 and NV
A.17. When using English, it is also important to be aware of the effects of swerve (see NV 4.14
and NV 7.12) and throw (see NV 4.15, NV 4.16, NV A.21, and my August '06 through July '07
articles). Sometimes, the phrase "effective squirt" or the term "squerve" is used to refer to the
net effect of both squirt and swerve on the shift in the CB position at object ball (OB) impact (see
my August '07 article for more information). If you want to refer back to any of my past articles,
they are all available on my website (billiards.colostate.edu).