Carefully squeeze about 3 cm of mercury into the capillary. The mercury plug may separate during the filling of the capillary or as the result of student use. Use the extended plastic capillary of the filling pipet to remove separations. Students may be surprised at the small change in the height of the air column. Generally the students should keep the capillary tubes in each temperature bath approximately 3 minutes to allow the air column to adjust to its equilibrium length.
Boiling water causes burns.
Go to Top Precautions Because the capillary tubes are somewhat fragile, remind students to be careful with them. Like mercury thermometers, they should not be used as stirrers. Do not permit students to fill the capillaries. Use caution when sealing capillaries to avoid burns. Permit the tubes to cool to room temperature before filling.