Practice Assignment 11
Measuring the densities of sports equipment materials
Any solid material which offers a sports context is suitable, though ‘hi-tech’ materials should feature if possible. Wood, rubber, metals of different kinds and composite materials can all be used. A wide variety is desirable.
- Specimens should include regular and irregular shapes, and some that float.
- Each group of students should work with three specimens of a single material.
Different groups should use different materials.
The standard procedures distinguish between the density of a material, and the apparent density of a hollow or porous or solid foam object, such as a ball or buoyancy aid.
Students should be encouraged to quote all measurements with the appropriate unit. For their own laboratory measurements (with mass in grams and volume in cubic centimetres) the density will be in grams per cubic centimetre.
Note: Applied Science specifications give the abbreviation as g cm-3, not g/dm3.
Apparatus and Reagents
- Standard Procedure:
- SP 0011:2005 Method for determining the density of materials
- Part 1: Determining the density of regular-shaped objects
- Part 2: Determining the density of irregular-shaped objects (Displacement can method)
- Part 3: Determining the density of irregular-shaped objects (Buoyancy method)
- SP 0011:2005 Method for determining the density of materials
- balance that can weigh an object suspended underneath it to the nearest 0.01 g
- ruler measuring in centimetres with millimetre graduations
- displacement can, larger than the test specimen
- measuring cylinder, large enough to catch the displaced water
- thread, as thin as possible, but strong enough to hold the test specimen
- beaker of water, large enough to submerge the test specimen
- waterproof thread (e.g. nylon), as thin as possible, but strong enough to hold the test specimen
Test Specimens
- selection of sports related materials (See above)
- small enough to immerse in displacement can and beaker
- pieces of broken equipment may be suitable