Viscosity is a function of:

1. viscosity of the medium (i.e., the viscosity of the solvent)
2. density of the medium
3. density (of the whole system??--I need a reference to confirm this)
4. number density of particles
   number of particles divided by the sum of
   1. the number of particles
   2. the number of medium particles
5. radius of the "drain"
6. shear rate
7. thermal energy (Boltzmann constant multiplied against temperature)
8. elapsed time

In its simplest form, viscosity is a measure of flow time, and hence, it has the units of seconds. Shear

A simple viscosity determination using an Ubbelholde will involve

1. Filling the viscometer with pure solvent to a given level, and then measuring the drain time for the pure solvent, .
   
   
2. Filling the viscometer with the same solvent with a dilute concentration of dissolved polymer and measuring the drain time again, . It will take longer because of the increase in viscosity:
   is greater than
   
   
   
3. Calculating, . This will give you a number greater than 1, with no units.

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Here is the equation for specific viscosity, :

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For the viscosity experiment, the disolved polymer coil is approximated by an "equivalent sphere." In a homework problem you may be given the radius the equivalent sphere, from which you can calculate the volume of the equivalent sphere:

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Here is the relationship between intrinsic viscosity, , and the volume of equivalent spheres:

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Here is the equation for intrinsic viscosity :

Viscosity is related to coil expansion by the Universal constant, .

Here is a theoretical equation for "generic" viscosity: