Abstract

Stephanie Rotan

This experiment involves the observations of different shaped drops of liquids of varying viscosities. The purpose is to observe and compare these different forms. The hypothesis is that the liquids with the higher viscosities will form longer necks on their drops than the liquids with lower viscosities. The necks of the higher viscosity fluids should stretch further before breakage of the drop from the burette. The seven liquids, water, glycerin, 10W-40, 10W-30, an 88% glycerin mixture, a 90% glycerin mixture, and ethyl alcohol were each tested for their average viscosity by filling a tube with the liquid and dropping a metal ball in it to time its fall. Next, each liquid was put into a burette and dripped out at a slow rate. Graph paper was placed behind the burette, and the drops were filmed. The drop sizes and neck shapes were compared by using frame by frame analysis.

The ball dropping test concluded that the order of liquids from highest to lowest viscosity were: glycerin, 10W-40, 90% glycerin solution, 10W-30, 88% glycerin solution, water, and ethyl alcohol. The relative areas of the drops during the first four frames were from largest to smallest: water, 88% glycerin solution, glycerin, 10W-40, 10W-30, 90% glycerin solution, and ethyl alcohol. The longest neck length of each drop on the last frame before separation from the burette shows glycerin to have the longest neck length, followed by 10W-40, 10W-30, 88% glycerin solution, 90% glycerin solution, water, and finally ethyl alcohol.