Title
Further Investigations: Measuring Salinity
Table of Contents
- Other methods for determining the salinity of a water sample are described below. Obtain more information about these methods or try the methods yourself.
- Recover the salts from a sample of seawater by evaporating all the water from a 1,000 g sample of seawater, then weighing the solid salts that remain. The salinity of the seawater sample can then be calculated using the formula given at the beginning of this topic.
- Measure the electric current that flows between two electrodes immersed in a solution. The conductivity of a salt solution is directly related to the salinity.
- Measure the angle at which light is refracted or bent by a solution using a refractometer. A refractometer measures the amount of light that is refracted by a solution. Solutions of greater salinity refract more light.
- Using the procedure in the activity, construct a hydrometer and a density graph to be used for solutions at other temperatures. For example, cool the solutions to 10˚C and repeat the procedures.
- Using your hydrometer, determine the salinity of samples of different types of water, such as tap water, rainwater, water from a stream or lake, an estuary, the seashore, the open ocean, and freshwater or seawater aquaria.
