Ball
Whether 40mm sized table tennis ball spins more or less than 38mm?
Table tennis
The international rules specify that the game is played with a light 2.7 gram, 40 mm diameter ball. The rules say that the ball shall bounce up 24–26 cm when dropped from a height of 30.5 cm onto a standard steel block thereby having a coefficient of restitution of 0.89 to 0.92. The 40 mm ball was introduced after the 2000 Olympic Games. However, this created some controversy as the Chinese National Team argued that this was merely to give non-Chinese players a better chance of winning since the new type of balls has a slower speed, while at that time most Chinese players were playing with fast attack and smashes. A 40 mm table tennis ball is slower and spins less than the original 38 mm (1.5 inch) one. The ball is made of a high-bouncing air-filled celluloid or similar plastics material, colored white or orange, with a matte finish. The choice of ball color is made according to the table color and its surroundings. For example, a white ball is easier to see on a green or blue table than it is on a gray table. Some Table Tennis balls have ball rated in stars so that more professional players can know which ball to use. Manufacturers often indicate the quality of the ball with a star-rating system, usually from one to three, three being the highest grade. As this system is not standard across manufacturers, the only way a ball may be used in official competition is upon ITTF approval. The ITTF approval can be seen printed on the ball.