Liverpool Mathematical Society Winter Lecture

Students from Year 10 and Year 12 attended the Liverpool Mathematical Society Lecture on the Fluid Dynamics of Chocolate Fountains.  The presenter, Dr Adam Townsend (Imperial College), explored the concept of viscosity in an effort to explain why chocolate (in a fountain) flows both downwards and inwards. He introduced us to the concept of shearing, using graphs of y=cx to the power of n to explain possible relationships between viscosity and shear rate.  We learned that viscosity of small molecules, such as water and the gases in air, does not change during normal shearing however more complex mixtures, such as chocolate, mayonnaise, toothpaste and ketchup tend to become less viscous on shearing.  While these mathematical models may seem frivolous, there are incredibly elegant uses for such non-Newtonian fluids. 

  • The next generation of bullet proof vests could be made from Kevlar packed with such a fluid which gets harder when impacted. 
  • In Canada potholes are currently filled by essentially pouring in a mixture of cornflour and water, then adding a thin layer of tarmac on top…when vehicles pass over this mixture, the mixture gets harder!
  • Ballet shoes can also be filled with these non-Newtonian fluids to increase stability while on point.

 

Adam Townsend proved to be an incredibly charismatic and engaging lecturer and made us all understand a little more about maths…so mission achieved!