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.
What is Brownian Movement. What Brown observed was that the motion within pollen grains (suspended in water) seemed to move around the liquid seemingly at random. This intrigued him and he began to study why this was happening, and tried to establish what force was driving these random fluctuations and changes in direction.