Tmrw my exm plz give me soon reply ,about Measurment of viscosity and viscosity.

http://en.wikipedia.org/wiki/Viscosity

To measure viscosity, you can use a viscometer, which is a device specifically designed for this purpose. There are different types of viscometers available, but the most commonly used one is a rotational viscometer. Here's a step-by-step guide on measuring viscosity using a rotational viscometer:

1. Set up the viscometer: Start by assembling the viscometer according to the manufacturer's instructions. Make sure it is clean and free from any debris or residue.

2. Calibrate the viscometer: Before measuring viscosity, it is important to calibrate the viscometer using a standard reference fluid with a known viscosity. This ensures accurate and reliable results.

3. Prepare the sample: Take the substance whose viscosity you want to measure (e.g., a liquid or a semi-solid) and prepare it by ensuring it is at the desired temperature and free from any air bubbles or contaminants. This may involve heating or cooling the sample and using techniques like degassing.

4. Take the measurement: Place the prepared sample into the viscometer's cup or chamber, ensuring it is filled to the specified level. Start the rotational motion of the viscometer at a controlled speed.

5. Observe and record the results: As the viscometer rotates, it generates a torque that is related to the viscosity of the sample. The viscometer's display will show the viscosity measurement based on this torque. Take note of the measurement and record it for further analysis or comparison.

Viscosity itself is a measure of a fluid's resistance to flow. It can be defined as the internal friction or "thickness" of a fluid. Fluids with high viscosity flow more slowly than fluids with low viscosity. Examples of high-viscosity fluids include honey, molasses, or engine oil, while low-viscosity fluids include water or gasoline.

Understanding the concept of viscosity is important in various fields such as engineering, chemistry, and material sciences. It helps in determining the behavior of fluids during processes like pumping, mixing, or coating.