The liquids having high internal momentum resistance which resist deformation are called high viscosity liquids.
High viscosity liquids are those liquids whose viscous forces are much higher as compared to other liquids, which makes the flow of liquid stuck at a point making the movement of liquid slow and sluggish resisting the transfer of internal momentum.
An Introduction to High Viscosity Liquids
Water is a basic necessity of our day to day life. Every living being require water for clenching their thirst and other daily uses. Similarly, we use vegetable oil for cooking our food. But, have you ever wondered why water flows fast while the vegetable oil takes much more time to flow?
In the first case, water has low internal resistance to flow due to which its momentum is easily transferred causing it to shear easily and its molecules flow quickly described as having low viscosity. On the other hand, vegetable oil has high internal resistance to flow barring the momentum transfer causing it to flow sluggishly and resist deformation described as having high viscosity.
Let us now take another example to make it more convenient for understanding. Take a bottle of milk with a thin neck. Now, take a container and pour the milk into the container. You will observe that the speed of milk flowing out although being poured from a thin necked bottle to the container is still good. Also, a negligible amount of milk settles in the bottle and at the neck of the bottle. You will also notice that the contact between air and milk is negligible.
Now, take another similar bottle with a thin neck but this time filled with mayonnaise. Again, take another container and now pour mayonnaise from a thin necked bottle into that container.
You will observe this time that the speed of mayonnaise flowing out of that small necked bottle is much slower than the speed of flow of milk from a similar bottle. You will also see that a lot of mayonnaise while being extracted out of the thin necked bottle gets stuck on the surface of the neck of the bottle making the opening, even more, smaller for mayonnaise to come out.
Even after that the mayonnaise which came out makes longer-term contact with the air with respect to the milk and doesn’t even take the shape of the container. This clearly illustrates that the viscous property which resists the internal momentum in milk is much less as compared to mayonnaise.
Considering the above examples, we can conclude the following statement about “High Viscosity Liquids” :
“Liquids having high internal resistance where the viscous forces obstruct the transfer of momentum causing it to flow sluggishly and resist deformation are called High Viscosity Liquids.”
Different ways to determine its viscosity
The viscosity of a liquid is something that can be determined by different ways and methods. These measurements are used to compare whether the liquid is highly viscous or low viscous with respect to other liquids. This can be done either by oneself or by using a standard measuring device called viscometer (a device used to measure the viscosity of fluid).
Method – 1 (Done by Oneself)
As we know, the time-taking of liquids vary. For example, if we pour out water from glass to another vessel, it will be poured and transferred to another vessel taking the shape of that vessel in a short period. While, if the same thing is done by replacing water with honey.
The time taken by honey will be more as compared to the time taken by water. Moreover, one can see that interface or contact timing between honey and air compared to water and air takes far longer to settle. This experiment was done by oneself clearly illustrates how we can know if a liquid is highly viscous.
Method – 2 (By using Viscometer)
There are innumerous methods used since the past to find out viscosity. Also, there are many different types of viscometers developed and are being used till present. In general, viscometry has a vast history to explore.
As we know, the inter-particle forces which include friction and molecular attraction within the solution determine the viscous property of a liquid. And, by analyzing the base principles used by viscometer to determine the viscosity is verbalized into two distinct forms under process on how different types of viscometer determines viscosity:
The S.I. unit of Kinematic viscosity is m2/s, also called stokes (St) which is named after George Stokes.
As we got to know a lot about what are high viscosity liquids and how we can measure it. Let us now move a step further and get to know about some examples of high viscosity liquids.