Capillary Action 1 - Physics Demonstrations - Capillary Action 1 | Physics Undergraduate Labs

Mercury is highly toxic through inhalation and skin contact. As noted in the demo notes, mercury should NOT be used in modern demonstrations. Instead, use water with food coloring in one set of tubes and a non-wetting liquid alternative such as a dense organic liquid or simply discuss the mercury behavior theoretically while showing only the water demonstration.

Purpose

Two U-tubes (each with one wide and one narrow arm) show capillary rise with water and capillary depression with mercury, contrasting wetting and non-wetting behavior. Note: This demo is currently not in service -- one tube is broken, and mercury use is no longer recommended.

Two U-shaped glass tubes against a dark background, each with one wide arm and one narrow arm connected at the bottom

Figure 1: The two U-tubes used for comparing capillary rise (water) and capillary depression (mercury).

Safety Warnings

Danger: Mercury Hazard - Alternative Recommended

Purpose