Technology 1 Unit 4 Technology and Sport

Technology 1 Unit 4 Technology and Sport

Modern sports materials are subjected to powerful forces. When a racket hits a ball, the impact causes compression (= squeezing) and tension (= stretching), and may cause bending (= compression + tension). Repeated friction makes clothing wear (= erode) away. A bicycle pedal may break because of fatigue (= weakening) if it is turned the same way repeatedly.  Sports materials must have properties (= characteristics) to resist (= fight against) these forces. Equipment must be impact-resistant, fatigue-resistant, and tough (= difficult to break). Clothing must be wear-resistant, fit the body tightly and be aerodynamic (= able to move smoothly). Some materials should be rigid (= unbendable), others need to be flexible (= able to bend), or elastic (= able to change shape and return to their original shape). Some equipment must be hard (= able to cut, but not be cut by, other materials). For fast sports, equipment needs a high strength- to-weight ratio (combining strength with lightness). Special materials are used for making modern sports equipment and clothing:  • plastics — these are light and can be moulded into shape. Examples: polycarbonate (goggles), polyurethane (footballs), and polystyrene (inside bike helmets)  • fibres — materials such as Lycra and Kevlar are used for sports clothing.  • composites —these combine fibres and plastic and have a good strength-to-weight ratio. Examples: fibre glass (boats), graphite, and carbon-fibre (bicycle frames)  • laminates — these are formed from two or more layers of plastic or composite metals such as titanium and aluminium, and alloys such as chrome-molybdenum (cro-moly) combine lightness, strength, and corrosion- resistance

jeudi 10 mars 2011

podcasst from Oxford English for Careers, Technology 1 Teacher’s Resource Book Oxford University Press, 2007, by David Bonami; with additional material by Norman Glendinning