1. Introduction

1. Introduction

This experiment aims to understand the loss of energy better when an object falls onto a surface. This could allow us to make better tennis courts for tennis players.

1.1 Background Research 

Tennis is a racket sport that people can play individually against a single opponent (singles) or two players (doubles). Each player uses a tennis racket strung with a cord to strike a hollow rubber ball covered with felt over or around a net and into the opponent's court.

This investigation aims to test the effect of the bounce or change in elastic potential energy within a tennis ball when dropped on different surfaces.

Modern tennis balls must conform to specific criteria for size, weight, deformation, and bounce bars to be approved for regulation play. The International Tennis Federation (ITF) defines the official diameter as 6.54–6.86 cm (2.57–2.70 inches). Balls must have masses in the range of 56.0–59.4 g (1.98–2.10 ounces). Yellow and white are the only colours approved by the ITF. Most balls produced are a fluorescent yellow known as "optic yellow", first introduced in 1972 following research demonstrating they were more visible on television.

Tennis balls are filled with air and are surfaced by a uniform felt-covered rubber compound. The felt delays flow separation in the boundary layer, which reduces aerodynamic drag and gives the ball better flight properties. Often the balls will have a number on them in addition to the brand name. This helps distinguish one set of balls from another of the same brand on an adjacent court.

A synthetic Turf Tennis court is a surface composed of polypropylene or polyethene grass fibres infilled with a specially graded sand top dressing.  The resulting surface is slower and more forgiving, much like a clay court, without the maintenance and foul weather issues inherent with them. The specially designed sand filled surface holds firm, even after a heavy rain, reducing the wait time to minutes instead of hours. Tennis court owners and governments may adjust the sand level and size to the customers' preference for ball speed and foot play. A court with more sand will be slower and create a slip and slide effect more like a clay court. 

1.2 Research Questions 


The research question being addressed is which surface will tennis balls bounce the highest?

      1.3 Hypotheses

The hypotheses are that the ball will bounce the highest on the concrete surface and lowest on the grass surface.

Image Credit: Ethan Chan Song Yi, Goh You Jun, Kottaimuthu Shrinithi 

1.3.1 Independent Variables 

The independent variable is the surface the ball is dropped onto—turf, concrete, clay, grass, tile and wood.

1.3.2 Dependent Variables 

The dependent variable is the height the ball bounces to.

1.3.3 Constants 

The constants are the height the ball is dropped from, which is 50cm, the size of the ball, the shape of the ball, the material of the ball, the weight of the ball, the manufacturer of the ball, the force used on the ball when it is dropped which is expected to be 0 and the method we use to drop the ball.