# How to Calculate Viscosity?

How to Calculate Viscosity of Liquids, Fluids?

## Viscosity of Liquids/Fluids Calculation

The resistance of a fluid or liquid to flow is termed as the viscosity. It can be represented with unit Pascal seconds (Pas). Viscosity can be measured using various methods, where the most common is dropping a material like ball or marble in the liquid container. The material used should be less than or equal to half of the diameter of the cylinder and should sink in the fluid. This tutorial helps you to learn how to calculate viscosity of any liquids/fluids.

**Formula:**

**Viscosity = [2 (p**_{s} - p_{l}) gr^{2}] / 9v

**Where,**

p_{s} - density of material used

p_{l} - density of liquid

g - Acceleration due to gravity (constant)

r - Radius of the Sphere

v - Velocity of the Sphere

**Step 1 : **Consider a ball of radius 2 m and velocity 0.07 m/s with density 7 g/mL is dropped into a liquid with density 1.8 g/ml. Find the viscosity of the liquid.

Given,

Radius of ball = 2m

Velocity of ball = 0.07 m/s

Density of ball = 7 g/mL

Density of Liquid = 1.8 g/mL

Acceleration due to gravity = 9.8 m/s^{2}

**Step 2:** Applying the values,

Viscosity = [2 (7- 1.8) 9.8 x 2 x 2] / 9 x 0.07

= [2 x 5.2 x9.8 x 2 x 2] / 0.63

= 407.68 / 0.63

= 647.11 Pas

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