Why is Density Necessary in the Viscosity Comparison Method?

In summary, the conversation discusses the equation for determining viscosity using an Ubelohde viscometer. The equation is derived by comparing the viscosity, density, and time of a known liquid to those of an unknown liquid. The conversation also addresses the significance of including density in the equation and why it cannot be neglected. The viscosity times density times time for flow is a constant in this viscometer design.
  • #1
thedy
77
0
Hi,I don know if my question will be clear,but I will try it.So,I m wondering how was derive this equation:
viscosity=viscosity(known liquid)*density(known from table)*time(liquid will get over one point of Ubelohde viscometer to second point of viscometer(unknown liquid)/density(known liquid)*time(liquid will get over one point of Ubelohde viscometer to second point of viscometer(unknown liquid).
So once again in short form:viscosity*density*time/density*time.
So,I know it is a comparison method,that means density*time/density* time is undimensional and that means,that viscosity=density*time in this case.
And now my question:Why density in this equation?Why not only weight?Or why not to neglect density and count only time?Why is density necessary here?
Thanks for patient and widespread answer.
 
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  • #2
In this viscometer design, apparently the viscosity times density times time for flow is a constant.
 

1. What is the viscosity comparison method?

The viscosity comparison method is a technique used to measure the viscosity, or resistance to flow, of liquids. It involves comparing the flow rates of two different liquids under the same conditions to determine their relative viscosities.

2. How does the viscosity comparison method work?

The viscosity comparison method works by using a viscometer, which is a device that measures the flow rate of a liquid. The two liquids being compared are poured into separate compartments in the viscometer, and the time it takes for each liquid to pass through a specific point is recorded. The liquid with the longer flow time has a higher viscosity.

3. What are the advantages of using the viscosity comparison method?

One advantage of the viscosity comparison method is that it is a simple and inexpensive way to measure the viscosity of liquids. It also does not require complex equipment or specialized training, making it accessible to a wide range of scientists and industries.

4. What are the limitations of the viscosity comparison method?

The viscosity comparison method is limited to measuring the relative viscosities of liquids, rather than providing an exact numerical value. It is also not suitable for highly viscous liquids or those that contain particles, as these can clog the viscometer and affect the results.

5. In what industries is the viscosity comparison method commonly used?

The viscosity comparison method is commonly used in industries such as food and beverage, pharmaceuticals, and petroleum. It is also used in research and development to study the properties of different liquids and their applications in various products and processes.

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