Ominaispaino

Ominaispaino, often translated as specific gravity, is a dimensionless quantity that is the ratio of the density of a substance to the density of a reference substance. Typically, for liquids and solids, the reference substance is water at its densest point, usually 4 degrees Celsius. For gases, the reference substance is often air at a specified temperature and pressure. Ominaispaino indicates how many times denser a substance is compared to the reference.

It is calculated by dividing the density of the substance (mass per unit volume) by the density of the reference substance. Since both density values will have the same units, the units cancel out, resulting in a dimensionless number. For example, if a substance has a density twice that of water, its ominaispaino is 2.

This property is useful for identifying substances and for understanding buoyancy. Objects with an ominaispaino less than 1 will float in water, while those with an ominaispaino greater than 1 will sink. Similarly, the concept applies to gases and their behavior in air. Ominaispaino is an intrinsic property of a substance under specific conditions of temperature and pressure.