The overall formula is complicated, so we won't show it here explicitly. In our density of water calculator, we use a method proposed by Millero and his coworkers. This quantity is usually given in per mille ‰, parts per thousand (ppt), or practical salinity units (psu), which are basically equivalent. In other words, mixing a mass of pure water, m₀, with a mass of salt, m₁, gives you the salinity S of salt water. Where m₀ is the mass of pure water and m₁ is the mass of salt. The basic parameter that tells us about the amount of salt in salt water is salinity, S, given as: The mixture of water and salt hereafter referred to as salt water has a different density than pure water. Although the outcome is an approximation, it's provided with sufficient precision. We use scientific notation to express all of the small values more clearly. Where the temperature T is in ☌, and the values of coefficients are the following: To get around this, our water density calculator uses an approximate equation based on the 5 th order polynomial: While there are tables of pure water density between water's freezing point ( 0 ☌ or 32 ☏) and its boiling point ( 100 ☌ or 212 ☏), there isn't a straightforward formula which yields the exact value for a given temperature.

Water has an intriguing property – it reaches its maximum density at about 4 ☌ or 40 ☏. Qualitatively, it's fairly simple, but from a mathematical point of view, estimating the outcome is a different story. As a result, the mass stays constant, but the volume increases, causing the density to decrease. You probably know of the phenomenon of the density of water changing at different temperatures, even if you've never thought about it in scientific terms ever wondered why ice floats? This change is mainly caused by thermal expansion – where the same amount of substance occupies more and more space as the temperature increase.

Density of water in lbft3