Salinity measurement refers to the process of determining the concentration of salt in water. This is important for various fields, including oceanography, environmental science, and aquaculture. Salinity is typically expressed in parts per thousand (ppt) or practical salinity units (PSU), and it can affect water density, marine life, and ecosystem health. There are several methods for measuring salinity, including conductivity, refractometry, and evaporation. Conductivity meters measure how well water conducts electricity, which increases with higher salinity. Refractometers use the bending of light in water to estimate salt concentration, while evaporation methods involve measuring the weight of salt left after water evaporates.