Quick Answer: Hare’s Apparatus is used to compare the densities of two liquids with two vertical glass tubes joined at their upper ends to a suction tube. When air is drawn out, each liquid rises in its tube, and the column heights give their relative density.
Last updated: October 2026
Key Features
Two vertical glass tubes joined by a connecting tube
With the lower ends in two beakers, gentle suction lowers the pressure in both tubes equally, so the liquids rise until their columns balance the same pressure difference. The less dense liquid stands higher, and the ratio of the measured heights gives the relative density, a common practical on hydrostatic pressure and specific gravity.
Frequently Asked Questions
How does Hare’s Apparatus compare densities?
Both tubes share the same reduced pressure, so the liquid columns rise to heights in inverse proportion to their densities; measuring the two heights gives the relative density.
Which liquids can be compared?
The source lists water, salt solution, glycerine and kerosene among suitable laboratory liquids.
