Rinsing after washing is a necessary process if you use detergents. In modern conditions, washing machines carry out all the washing, rinsing and spinning automatically, but not all housewives use mechanized washing constantly.
Rinsing should begin in warm water, and end in cold water, but its temperature should only be slightly lower than room temperature, otherwise your hands will not withstand long in ice water. Why is it more efficient? The fact is that under the influence of hot water during washing, the fibers of the fabric swell, deform. If they are not squeezed to their usual state under the influence of cold water, the fabric will wear out faster, and in addition, after drying, the thing may turn out to be of an unusual size or shape. But in order for the recovery process to go as delicately as possible for the fabric, it is necessary to cool the water during rinsing gradually: first make it warm, and make it cooler with every next water change. In addition, with the help of cold water, soapy substances are better removed from the fabric.
Why it happens?
One can understand this process only by considering the mechanism of its action at the molecular level. During heating, the kinetic energy of the water molecule grows, each individual drop seems to be slightly flattened and reduced in size, and the tissue fibers stretch, become swollen and supple. At this time, the molecules of hot soapy water are much easier to penetrate the structure of the fibers and take with them adhering parts of the dirt. But many of them remain in the structure of the fabric and the task of cold water when rinsing will remove them from there.
When cold water affects the tissue after hot water, the drops from the flattened form again tend to become spherical, return to their original state, since the kinetic energy of each molecule decreases. At the same time, the fibers of the fabric are compressed again and soap droplets pop out of them, and the fabric is washed well and becomes clean and fresh.
