Pycnometers & Specific Gravity

Reliably obtain density and specific gravity measurements with DWK’s pycnometers. DWK’s high-quality Wheaton® and KIMBLE® pycnometers, also known as specific gravity bottles, are ideal for use with a variety of substances, such as liquids and semi-solid and solid materials.

  • Available in a conical shape with a flat base for maximum stability.
  • Manufactured from 3.3 borosilicate glass for high thermal shock resistance.
  • Offered in an assortment of capacities ranging from 10 to 50 mL.
  • Provided with a close-fitting ground glass stopper with a built-in capillary tube.
  • Most pycnometers are supplied with a standard taper thermometer.

Pycnometers & Specific Gravity FAQs

Pycnometers & Specific Gravity

Frequently Asked Questions

A pycnometer is used for measuring the density or specific gravity of liquids and semi-solid and solid materials.

The density of a liquid is calculated by:

  1. Obtaining the mass of the liquid—subtract the weight of an empty pycnometer from the weight of the same pycnometer filled with the liquid.
  2. Determining the volume of the liquid—use the volume markings on the pycnometer to measure the volume of the liquid. Dividing the mass of the substance by the precise volume of the liquid to obtain the density (g/mL).

During measurement, the pycnometer and sample should be maintained at the same temperature or the density will change.

Procedure for specific gravity of soil by pycnometer method:

Before starting, make sure that the pycnometer and liquids are maintained at the same temperature.

  1. Using a clean and dry pycnometer of a known capacity, take its weight with the stopper on (M1).
  2. Add oven dried soil in the pycnometer. With the stopper on, determine the weight of the pycnometer with dried soil (M2).
  3. Add enough distilled water to the pycnometer to cover the soil. Use a vacuum pump or gently swirl the contents to remove any entrapped air. Disconnect the vacuum pump if one was used. Fill the pycnometer completely with distilled water. Dry any excess water on the outside of the pycnometer. With the stopper on, determine the weight of the pycnometer with the soil and distilled water (M3).
  4. Empty the pycnometer. Clean it and wipe it dry. Fill the pycnometer with distilled water only. Dry any excess water on the outside of the pycnometer. With the stopper on, determine the weight of the pycnometer with distilled water only (M4).

The specific gravity (G) of soil is determined using the following equation:

G=M2-M1÷(M2-M1)-(M3-M4)

Procedure for specific gravity of a liquid by pycnometer method:

Before starting, make sure that the pycnometer and liquids are maintained at the same temperature.

  1. Using a clean and dry pycnometer of a known capacity, take its weight with the stopper on (M1).
  2. Add distilled water to the pycnometer. With the stopper on, determine the weight of the pycnometer with distilled water (M2).
  3. Empty the pycnometer. Clean it and wipe it dry. Fill the pycnometer with liquid X. Dry any excess liquid on the outside of the pycnometer. With the stopper on, determine the weight of the pycnometer with liquid X (M3).

The specific gravity (G) of liquid X is determined using the following equation:

G=M3-M1÷M2-M1