| Bowling can be traced back to approximately | | | | great majority of bowlers involves a delivery |
| 5200 B.C., when the ancient Egyptians used | | | | that starts the ball in a skid that evolves |
| stones for their balls. | | | | into a roll that hooks into the pins. |
| | | | |
| The first bowling balls used in the United | | | | It has been known since before the 1960s that |
| States were made of wood, especially oak. In | | | | a "full-roller" type of delivery does not |
| about 1906 the first hard rubber balls were | | | | hook as well as "3/4 rollers" on oily lanes. |
| produced, and these remained the standard | | | | On successive rotations, the "full roller" |
| until the 1960s and 70s. These decades saw | | | | repeatedly contacts the lane on the same full |
| the emergence of plastic (polyester) balls. | | | | circumferential circle, on which the oil |
| | | | accumulates, making it harder for the |
| In the early 1970s, people began | | | | side-roll to find traction and create hooking |
| experimenting with the hardness of the | | | | action. The "full-roller" had been the |
| plastic balls, notably PBA member Don McCune, | | | | dominant choice before the changes in lane |
| who invented the "soaker" - a plastic | | | | coatings and oil. The "semi-roller" is now |
| (usually polyester} ball he softened "in the | | | | preferred (it may also be called "3/4 roller" |
| garage" with chemical solvents. These and | | | | or by other slang terms). With a 3/4-roller a |
| balls subsequently manufactured with the | | | | bowler puts the ball into a rotation whose |
| resulting softer cover came under USBC | | | | contact ring is smaller, and on successive |
| scrutiny because of the increased scoring. A | | | | rotations enlarges (subsequent examination of |
| ball hardness rule was established, based on | | | | the ball often shows a flaring of the circles |
| durometer readings, which barred some of the | | | | of oil). This is because at every spot along |
| softer balls. | | | | the circle friction reduces the rotation, and |
| | | | that includes the spin component, causing |
| At some point in ball making and drilling the | | | | rotation on a continually larger circle. This |
| USBC introduced ball balance regulations to | | | | has the effect of bringing relatively dry |
| prevent people from taking advantage. It was | | | | ball surface in contact with the lane, |
| possible to drill the grip at a location | | | | increasing traction for both forward-roll and |
| relative to the weight block so that it would | | | | side-roll. It probably goes without saying |
| achieve some effect, such as to help the | | | | why bowlers often wipe oil off the ball. |
| bowler make it roll earlier or hook more. | | | | |
| | | | Another effect of ball imbalance (either |
| In 1984 AMF and Columbia began manufacture of | | | | static or dynamic) is the ability to |
| the very first polyurethane cover stock | | | | introduce gyroscopic effects on the rotation. |
| bowling balls, the AMF Angle and Columbia | | | | The component of imbalance along the rotation |
| U-Dot, and this one change-likely meant to | | | | axis provides a leverage that can change the |
| allow the ball to get a better grip on the | | | | orientation of the axis on its horizontal |
| similar polyurethane varnishes used on | | | | plane, an action physicists call precession. |
| natural wood finish lane surfaces-changed the | | | | It is basically the same thing as a spinning |
| nature of the bowling game significantly, as | | | | toy top "going around in a circle." In the |
| never before. | | | | case of a rotating bowling ball, as it moves |
| | | | along the lane, there is only time for its |
| Prior to about 1990, the USBC "static" ball | | | | total rotation axis to move along a short |
| balance regulations were adequate. The core | | | | arc, but this is enough to reorient the total |
| was usually a uniform sphere centered inside | | | | rotation so that some of the forward-roll |
| the ball. Then competition among ball | | | | becomes side-roll, increasing the side-roll |
| manufacturers motivated the production of | | | | provided in the bowler's delivery, thereby |
| balls designed to offer more than the "static | | | | achieving more hook. It is possible to use |
| balance" tricks. Materials and fabrication | | | | dynamic ball balancing to achieve a stronger |
| changes have since allowed the assembly of | | | | gyroscopic effect than static balancing |
| balls whose interior components have a much | | | | alone. |
| greater range of density, thereby offering a | | | | |
| new ball choice that, in physics terms, | | | | The advent of dynamic ball balancing meant |
| involves the moment of inertia of a solid | | | | that bowlers could achieve "ball flare" |
| sphere. Eventually, "dynamic balance" | | | | without the need for a 3/4 roller delivery, |
| regulations had to be adopted. | | | | and more hook. Additionally, balls with |
| | | | covers that create higher friction, such as |
| Weight Block Basics | | | | "particle" balls, provide for more traction |
| | | | and hook. Bowlers are embracing these |
| In order to continue this discussion, a | | | | choices, buying balls whose characteristics |
| systematic description of ball rotation must | | | | complement or enhance their deliveries. |
| be introduced. For various formulaic | | | | |
| purposes, physicists divide rotation into | | | | It is the opinion of many people in the |
| three components, assigning portions to x, y | | | | bowling community that these advances in |
| and z axes that are mutually perpendicular. | | | | bowling ball technology have actually |
| For bowling, the x-axis can be assigned to a | | | | undermined bowling skill and have made it |
| line that is parallel to the foul line, the | | | | more difficult for lane maintenance personnel |
| y-axis to the line parallel to the boards, | | | | to lay out fair and credible conditions for |
| and the z-axis to the vertical. Forward-roll | | | | participants. This is because advanced |
| is rotation about the x-axis, side-roll is | | | | players using hi-tech balls "need" more oil |
| rotation about the y-axis and mid-roll (or | | | | to score high and might complain about the |
| spin) is rotation about the z-axis. The pure | | | | radical behavior of their balls on "dry" |
| full-roller delivery is a combination of | | | | lanes. At the same time, less aggressive |
| forward- and side-roll only. Semi-rollers | | | | players might complain when they can't get |
| include spin. Spinners may have very little | | | | their balls to hook. These complaints have |
| side roll. In a very strict physics sense, a | | | | actually been part of the game throughout |
| ball may be delivered with rotation, but | | | | USBC history. It's just been a matter of |
| usually not in a roll, because that would | | | | which group prevails within the USBC - or |
| imply complete traction. The technique of the | | | | what new technology comes along next. |