Density and Sound

Under the guidance of supervisor Clive Davies (right) at Massey University's School of Engineering and Advanced Technology, PhD student Emile Webster (left) is developing a technique to measure volume without using water.

With a Helmholtz resonator and specifically designed computer software, the volume of items such as kiwi fruit can be measured. This in turn can be used to calculate the density of the fruit, which gives an indication of ripeness.

The technique can also be used to measure other types of fruit and vegetables, mineral samples, and in some instances powders.