All substances have a certain density. Depending on the occupied volume and the set weight, density is calculated. It is, proceeding from experimental data and numerical transformations. Besides, density depends on a set of various factors in connection with which its constant value changes.
Instruction
1. Imagine that some vessel to the brim filled with water is given. It is necessary to find water density in a task, at the same time without knowing either the weight, or volume. To calculate density, it is necessary to find both parameters experimentally. Begin with determination of weight. Take a vessel with water and put it on scales. Then you will pour out of it water then again put a vessel on the same scales. Compare results of measurements and receive a formula for finding of mass of water: mob. - mc.=mv., where mob. - the mass of a vessel with water (lump), mc is the mass of a vessel without water. The second that will be required to be found is a volume of water. Pour water in a measured vessel, then determine by the scale which is available on it what volume of water contained in a vessel. Only after it on a formula find water density: ρ=m/VС it is only possible to determine by the help of this experience water density approximately. However, under the influence of some factors it can fluctuate. Get acquainted with the most important of such factors.
2. At t=4 °C water temperature water has density ρ=1000 кг/м^3 or 1 г/см^3. At temperature change also density changes. In addition, pressure, a mineralization and salinity of water carry to the factors influencing density. Most pronounced influence on temperature density. Remember that density under the influence of temperature changes under the parabolic law. The t=4 °C value is a critical point of this parabola on which density of water reaches the greatest value. Any temperature which is above or below this value leads to decrease in density. At a temperature of 0 °C water density considerably goes down.
3. The mineralization and pressure affect water density equally. At their increase density grows. Also noticeable density of water is directly proportional to concentration of salt in it. There are also other factors on which water density depends, but their influence is much weaker, than at stated above.