Core Practical 8: Determining the Tensile Strength of Plant Fibres (Edexcel International A Level Biology): Revision Note

Determining the Tensile Strength of Plant Fibres

• The tensile strength of a fibre refers to the maximum load it can carry before breaking

  • For example, this information would be important when determining the strength of a rope made of plant fibres

Apparatus

• Plant fibres

• Retort stand (clamp stand)

• Clamp

• Weights

Method

1. The fibre should be attached to a clamp stand

2. Attach a weight on the other end of the plant fibre

3. Carefully continue to add one weight at a time until the fibre breaks

4. Record the mass at which the fibre broke

5. This represents the tensile strength

6. To increase the accuracy of your results, this process should be repeated with more samples of the same plant fibre

   • These values can be used to calculate the mean tensile strength for the fibre

   • It is important to ensure that the fibres are all of the same length and that all other variables are kept constant

Apparatus used to determine the tensile strength of plant fibres