# Comparison of the densities of water, potassium mercury iodide, and mercury

Comparing the densities of mercury, potassium tetraiodomercurate(II) solution, and water illustrates that barometers made from the three liquids have different heights.

These three containers hold approximately equal masses (about 300 grams) of water, potassium mercury iodide solution, and mercury. A mercury barometer is about 2.2 feet tall. Potassium mercury iodide [potassium tetraiodomercurate(II) solution] has a different density and volume and can can be used to make an eleven or twelve foot barometer. Water, the lest dense of the three, would make a 40 foot barometer.

Credits:
• Design and Demonstration