Quick Answer: The Stalagmometer is a borosilicate glass instrument with a capillary tube, used to find the surface tension of a liquid from the drops that fall from its tip. Readings are compared with a reference liquid such as water, by the drop number or drop weight method.
Last updated: October 2026
Key Features
Borosilicate glass with a glass capillary tube
Measures surface tension relative to a reference liquid such as water
Drop number method: counts drops from a fixed volume
Drop weight method: uses the mass or volume of a single drop
Follows the classic method attributed to Traube
Technical Specifications
Specification
Value
Material
Borosilicate glass
Principle
Drop number or drop weight (Traube) method
Reference liquid
Water or another known liquid
Typical liquids
Water, alcohol, surfactant solutions
About This Product
In a physical chemistry practical, students count the drops of water and of a test liquid that fall from the same volume, and work out the surface tension of the test liquid by comparison. Adding salt or detergent to water and repeating the count shows how solutes change surface tension and how cohesion sets drop size. Educational Instrument can dispatch the Stalagmometer to laboratories in Côte d'Ivoire, Vietnam, Seychelles, Saudi Arabia, Mongolia and Panama.
Frequently Asked Questions
How does the Stalagmometer measure surface tension?
It compares a liquid with a reference such as water, either by counting the drops formed from a fixed volume or by finding the mass or volume of a single drop.
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