sentence: Balls are marked with different coloured dots.
sentences_before: The ball is made of rubber. It is hollow. When it is warm it bounces more.
sentences_after: They are made to bounce at different speeds depending on the colour of the dots. Balls with yellow dots are slow. Balls with green or white dots are average. Balls with red dots are fast.
concept_name: ball
headings: Squash (sport) Playing equipment The ball
categories: Racquet sports