It is commonly believed that hard wooden, round balls were the first balls used for golf between the 14th through the 17th centuries. Though they were undoubtedly used for other similar contemporary stick and ball games, made from hardwoods such as beech and box trees, there is no definite evidence that they were used in golf in Scotland. It is equally, if not more likely, that leather balls filled with cows' hair were used, imported from The Netherlands from at least 1486 onwards. Then or later, the featherie ball was developed and introduced. A featherie, or feathery, is a hand-sewn round leather pouch stuffed with chicken or goose feathers and coated with paint, usually white in color. The volume measurement for the feathers was a gentleman's top hat full of feathers. The feathers were boiled and softened before they were stuffed into the leather pouch. Making a featherie was a tedious and time-consuming process. An experienced ball maker could only make a few balls in one day, and so they were expensive. A single ball would cost between 2 shillings and 5 shillings, which is the equivalent of 10 to 20 US dollars today.
There were a few drawbacks to the featherie. First, it was hard to make a perfectly round, spherical ball, and because of this, the featherie often flew irregularly. Also, when the featherie became too wet, its distance would be reduced, and there was a possibility of its splitting open upon impact when hit or when hitting the ground or other hard surface. Despite these, the featherie was still a dramatic improvement over the wooden ball, and remained the standard golf ball well into the 19th century.
The Rules of Golf, jointly governed by the R&A and the USGA, state in Appendix III that the diameter of a "conforming" golf ball cannot be any smaller than 1.680 inches (42.67 mm), and the weight of the ball may not exceed 1.620 ounces (45.93 g). The ball must also have the basic properties of a spherically symmetrical ball, generally meaning that the ball itself must be spherical and must have a symmetrical arrangement of dimples on its surface. Additional rules direct players and manufacturers to other technical documents published by the R&A and USGA with additional restrictions, such as radius and depth of dimples, maximum launch speed from test apparatus (generally defining the coefficient of restitution) and maximum total distance when launched from the test equipment.
In general, the governing bodies and their regulations seek to provide a relatively level playing field and maintain the traditional form of the game and its equipment, while not completely halting the use of new technology in equipment design.
Until 1990, it was permissible to use balls of less than 1.68 inches in diameter in tournaments under the jurisdiction of the R&A, which differed in its ball specifications rules from those of the USGA. This ball was commonly called a "British" ball, while the golf ball approved by the USGA was simply the "American ball". The smaller diameter gave the player a distance advantage, especially in high winds, as the smaller ball created a similarly smaller "wake" behind it.
When a golf ball is hit, the impact, which lasts less than a millisecond, determines the ball’s velocity, launch angle and spin rate, all of which influence its trajectory and its behavior when it hits the ground.
A ball moving through air experiences two major aerodynamic forces, lift and drag. Dimpled balls fly farther than non-dimpled balls due to the combination of these two effects.
First, the dimples on the surface of a golf ball cause the boundary layer on the upstream side of the ball to transition from laminar to turbulent. The turbulent boundary layer is able to remain attached to the surface of the ball much longer than a laminar boundary and so creates a narrower low-pressure wake and hence less pressure drag. The reduction in pressure drag causes the ball to travel farther.
Second, backspin generates lift by deforming the airflow around the ball, in a similar manner to an airplane wing. This is called the Magnus effect.
Backspin is imparted in almost every shot due to the golf club's loft (i.e., angle between the clubface and a vertical plane). A backspinning ball experiences an upward lift force which makes it fly higher and longer than a ball without spin.
Sidespin occurs when the clubface is not aligned perpendicularly to the intended direction of swing or ball-to-target line, leading to a lift force that makes the ball curve to one side or the other based on the direction of where the clubface is pointing at impact. The dimples allow both the sidespin to occur as well as to promote an angular upward lift. Some dimple designs are claimed to reduce the sidespin effects to provide a straighter ball flight.
To keep the aerodynamics optimal, the golf ball needs to be clean, including all dimples. Thus, it is advisable that golfers wash their golf ball whenever permittable by the rules of golf. Golfers can wash their golf balls manually using a wet towel or using a ball washer of some type.
Dimples first became a feature of golf balls when English engineer and manufacturer William Taylor, co-founder of the Taylor-Hobson company, registered a patent for a dimple design in 1905. William Taylor had realized that golf players were trying to make irregularities on their balls, noticing that used balls were going further than new ones. Hence he decided to make systematic tests to determine what surface formation would give the best flight. He then developed a pattern consisting of regularly spaced indentations over the entire surface, and later tools to help producing such balls in series Other types of patterned covers were in use at about the same time, including one called a "mesh" and another named the "bramble", but the dimple became the dominant design due to "the superiority of the dimpled cover in flight".
Most golf balls on sale today have about 250–450 dimples, though there have been balls with more than 1000 dimples. The record holder was a ball with 1,070 dimples—414 larger ones (in four different sizes) and 656 pinhead-sized ones.
Officially sanctioned balls are designed to be as symmetrical as possible. This symmetry is the result of a dispute that stemmed from the Polara, a ball sold in the late 1970s that had six rows of normal dimples on its equator but very shallow dimples elsewhere. This asymmetrical design helped the ball self-adjust its spin axis during the flight. The USGA refused to sanction it for tournament play and, in 1981, changed the rules to ban aerodynamic asymmetrical balls. Polara's producer sued the USGA and the association paid US$1.375 million in a 1985 out-of-court settlement. Polara Golf now manufactures balls with “Self-Correcting Technology” for non-tournament play.
Golf balls are usually white, but are available in other high visibility colors, which helps with finding the ball when lost or when playing in low-light or frosty conditions.
As well as bearing the maker's name or logo, balls are usually printed with numbers or other symbols to help players identify their ball.