PURPOSE: To measure the density of a liquid.
DESCRIPTION: If the hydrometer is immersed in a graduated cylinder filled with water, the reading on the scale (at right in picture) should be C(W) = 1000, indicating that the scale is calibrated for water. If the hydrometer is put into the saline solution, the number C(L) at the level of the liquid is read. The density D(L) of the unknown liquid is given by: D(L)=C(L)*D(W)/1000,where D(W) is the density of water in kg/m^3. One can measure densities between 0.7 and 2.0 using this device.
REFERENCES: (PIRA 2B40.60)
EQUIPMENT: Hydrometer, one-liter graduated cylinders with water and saline solution.
SETUP TIME: None.
Go back to Lecture-Demonstration Home Page.