tensile strength

• IV

  • the type of fibre used- from different plants
• DV


  The amount of mass that can be added before the fibre snaps
• CVS

  • length of fibre – each fibre should be roughly the same length for a fair comparison
  • Size of each individual mass – a set of the same weights can be used
• method

  1. fibre is removed carefully from plant
  2. Once the fibres have been removed, connect them between 2 clamp stands and gradually add mass in the middle until the fibre snaps. Note the mass required to snap the fibre.
  3. Try this again but with individual fibres from different plants and different ways of combining fibres (e.g. twists). You can also compare the tensile strength of the stem to the individual fibres.
• results/conclusions

  • You should observe that different species of plants have different tensile strengths of their fibres.
  • Cellulose is a key component of cell walls and has cross-linking thanks to strong, horizontal glycosidic bonds between glucose molecules and vertical hydrogen bonds between neighbouring chains (forming microfibrils). A mesh of microfibrils is then glued together with pectin and hemicellulose which allows for greater strength and flexibility.
• conclusions

  • Lignin is a chemical found in cell walls as well which gives cells support and waterproof capabilities. Middle lamella join adjacent cell walls together with calcium pectate – adding to the strength of the plant fibres. 
  • sclerenchyma fibres – these form long tubes for strength and support, featuring lignified walls as well.