Causes. Dry skin (xerosis) often has an environmental cause. Certain diseases also can significantly affect your skin. Potential causes of dry skin include: Weather. Skin tends to be driest in winter, when temperatures and humidity levels plummet. But the season may not matter as much if you live in desert regions. Heat.
Brownian movement. n. The random movement of microscopic particles suspended in a liquid or gas, caused by collisions with molecules of the surrounding medium.Also called Brownian motion, molecular movement, pedesis.he random movement of microscopic particles suspended in a liquid or gas, caused by collisions with molecules of the surrounding medium.
The botanist Robert Brown presented the concept of Brownian motion in 1827. He observed pollen grains in water under a microscope and saw that the pollen grains are moving here and there (random movement) in water. This movement was named as the Brownian motion.