Furthermore , since the screen vibrates vertically , there is a ' popcorn effect ' whereby the coarser particles are lifted higher and finer particles stay closer to the screen , thus increases the probability of separation .
Separation can not take place without stratification .
Since the screen vibrates vertically , there is a ' popcorn effect ' whereby the coarser particles are lifted higher and finer particles stay closer to the screen , thus increases the probability of separation .
Separation can not take place without stratification .