The potential effect of drop size on efficiency of splash-cup and springboard dispersal devices

Abstract

An equation was derived that gives the velocity of a water drop of given size after a given distance of fall. A 4-mm drop develops nearly 11 times the momentum of a 2-mm drop such as commonly occurs in rain. A 4-mm drop reaches about 47% terminal velocity after 1 m and about 91% after 8 m. It is suggested that most splash-cup and springboard mechanisms evolved under the canopies of humid forests where large drops can exert a very great selective stimulus.