Basketball Bouncing in Different Temperatures

BASKETBALL BOUNCING IN DIFFERENT TEMPERATURES

BACKGROUND INFORMATION

The construction of a rubber basketball consist of three parts. The Bladder, The Winding and

the Cover.

The Bladder

Sheets of material are bonded together with an attached valve and formed through vulcanization into a vessel or sphere that retains the air for the ball after inflation. Made from natural rubber and butyl rubber. The higher the percentage of butyl rubber, the better the air retention, therefore, the better the better the bladder.

The Winding

Threat-like textile material that is continuously wound around the bladder, a complex machine is used to rotate the bladder and at the same time apply the winding in a random, but uniform patter.

Types of winding.

Nylon - excellent tensile strength, can withstand temperature changes and some effects due to moisture.

Polyester - strong but very resistant to stretch, a small amount of stretch is necessary to retain uniformity.

Combinations of both Nylon and Polyester are very effective in maintaining uniformity.

The winding protects and reinforces the bladder to help it maintain its true shape.

The Cover

Sheets of rubber with a wide range of color pigments are attached to the windings and bladder then vulcanized to form the uniformly pebble ball. The rubber cover is made from a blend of natural and butyl rubber. The higher the percentage of natural rubber, the higher the bounce/rebound. The higher the percentage of butyl rubber, the better the durability. The molding of the cover must be uniform and complete to provide durability and to keep the windings intact.

A basketball bounces because of three factors: What it’s made of, how much air is inside and what it bounces against. The higher the percentage of natural rubber, the higher the bounce/rebound. Inside a regulation basketball we can see that there’s a rubber bladder filled with and surrounded by compressed air. If we look even deeper into the rubber bladder, we can see that molecules it’s made of are linked together in long, squiggly chains. Rubber and other substances with this unique molecular structure are called “polymers.” When the ball is at rest, those long molecular chains don’t have much to do but sit there tightly tangled together. When the player picks up the ball and starts dribbling, look what happens. Gravity first pulls the ball downward, creating energy of motion called “kinetic energy”. As the ball makes contact with the floor, the rubber’s molecular chains