coefficient of viscosity of water by capillary flow methodAim:To determine the coefficient of viscosity of water by capillary flow method, using graduated burette without stopper.

Apparatus required:Burette stand, graduated burette without stopper, Capillary tube, rubber tube, beaker, stop watch, water, funnel, wooden bench, etc.

Formula:The coefficient of viscosity of the water

Wherer = density of waterg = acceleration due to gravityr = radius of the capillary tubel = length of the capillary tubev = volume of water comes out of the capillary flow (5 cc)t = time taken for 5 cc flow of waterH = the average pressure head height of the liquid levels from the capillary tube.

h = height of initial level from the experimental table 1

h = height of final level from the experimental table 2

h = height of the axis of capillary tube from the table

Description:The graduated burette without stopper is mounted vertically in the stand. A rubber tube is connected to the bottom of the burette. To the other end of the tube, a capillary tube is inserted and placed in a perfectly horizontal position.

Procedure:Pure water is poured into the burette using a funnel. The height of the liquid level in the burette is adjusted such that there is a streamline flow of water through the capillary tube i.e. 5 to 8 drops per minute. This can be achieved by raising or lowering the capillary tube. When the water level in the burette comes to zero mark a stop watch is started and the time

for the water level to reach 5 cc, 10 cc, 15 cc, 20 cc and 25 cc mark is noted and entered in the tabular column I.From the above readings, the time of flow of 5 cc water (t) at various ranges like 0 cc to 5 cc, 5 cc to 10 cc, 10 cc to 15 cc, 15 cc to 20 cc and 20 cc to 25 cc are tabulated in tabular column II. In each case the heights of the respective initial levels and final levels from the experimental table are noted. The average pressure head height is calculated and entered in the tabular column. Substituting the average value of Ht values in the formula given, the coefficient of viscosity of water is calculated.OBSERVATION

Density of water = …………………kgm-3

Acceleration due to gravity g = ………………..ms-2

Radius of the capillary tube r = …………………mLength of the capillary tube l = …………………mVolume of water comes out of the cap. flow v = ………….5 cc= 5X10-6mTabular column I:To note the time taken for the flow of waterTabular column

Tabular column II:Height of the axis of cap. tube from the table h = m

Calculation:The coefficient of viscosity of water

Result:The coefficients of viscosity of water = ---------------Nsm-2