For the description of ocean currents accurate measurements of the density of sea water are of great importance. For this purpose, measuring instruments are needed which reach a small uncertainty.

The water tube level is simple: connect two empty water bottles with a length of hose, fill them with water, and measure the height of the water inside the tube. Since the two water bottles are ...

For the description of ocean currents accurate measurements of the density of sea water are of great importance. For this purpose, measuring instruments are needed which reach a small uncertainty.