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## Homework Statement

Hello everyone, I am doing an experiment and I've hit a snag with my calculations. I am looking at how concentrations of soap affect surface tension in water. I am have been using the capillary equation and capillary tubes for my calculations. I have practiced this method for 100% water and I have gotten the value of 2.36E-05 as my surface tension of water at 70 degrees F. I would assume that doing this correctly would give me the surface tension for water at 70 degrees F but as I look at other sources the values appear to be .0644 N/M. I am unsure and am looking for help as to where my methodological errors would occur for my value to be this off. I feel like I am missing something but I am unsure as to what it is. (All units should be SI)

## Homework Equations

Here is the capillary equation and the variables:

s=(phga)/2

s= surface tension

h= sifference in height between depth of water and the liquid in the capillary tube .0193 m

p= density (of water) =1

g= gravity (9.8) m/s

a= raidus (2.5x10-4) m

## The Attempt at a Solution

Raw data (h values)

1.95cm

1.95cm

1.9cm

Av: (1.95+1.95+1.9)/3 = 1.93cm = .0193m = h

h= .0193

p =1

g= 9.8 m/s

a= 2.5x10-4 m

s=((1)(9.8)(2.5x10-4)(.0193))/2

s= 4.7285x10-5

s= 2.364E-5 (final answer)