For scientific purposes, the Celsius Scale is used. The addition of small, precise quantities of chemical to a sample until an endpoint such as a color change is reached. The dissolved oxygen test involves a titration procedure using a digital titrator to add drops of a chemical to the water sample. The depth that light will penetrate water. A Secchi disk is used to measure the limit of visibility in water bodies such as lakes.
Light scattered by the suspended material is detected by a photocell.
The photocell converts the scattered light into an electrical current that is sent through the meter producing a numerical reading in NTUs. The resulting number is related to water quality, dissolved or suspended matter, and biological productivity. The physical, chemical, and biological characteristics of water as they relate to the use of the water. Van Dorn bottles, and less frequently, Kemmerer water samplers, are used on the vessels. The land area in which water drains toward a lake, stream, or river at a lower elevation.