Developed by food scientists at the Hebrew University in Rehovot, Israel, the device consists of a chamber in which a sample of food or other material is gradually crushed.
Microphones pick up the noise produced and generate a graph plotting decibels against time.
The result is a rugged line, made up of spikes and troughs. A computer expresses the wiggly line as a fractal dimension. The crunchier a potato chip is, explains Amos Nussinovitch, leader of the team that created the crunchmeter, the longer it will continue to produce noise as it is smashed into smaller and smaller pieces. This produces a more complex curve with a higher fractal number. He says a really crunchy cornflake will get a score of about 1.5.