Requirements (Instruments, Chemicals & Other):

● Ostwald viscometer
● Stopwatch or timer
● Beakers
● Pipette or dropper
● Thermometer (±0.5°C)
● Water bath (25°C)
● Suction bulb or rubber tubing
● Distilled water
● Test liquid (e.g., glycerin, alcohol)
● Density bottle
● Measuring cylinders (25 mL, 50 mL)
● Spatula
● Tissue paper or cotton
● Data recording sheets
● Calculator or computer for analysis

Procedure:

● Clean and dry the viscometer thoroughly before use.
● Fill the viscometer with distilled water up to the mark using a pipette.
● Immerse the viscometer in a constant temperature water bath (25°C) for 5 minutes.
● Using a suction bulb, draw the water above the upper mark.
● Start the stopwatch as the liquid crosses the upper mark and stop when it reaches the lower mark — record as t₂.
● Repeat three times and take the mean value.
● Empty and rinse the viscometer with the test liquid.
● Repeat steps 2–6 with the test liquid to record t₁.
● Measure the densities ρ₁ (test liquid) and ρ₂ (water) using a density bottle.
● Calculate the relative and absolute viscosities using the formulas provided.