Ms. Palmeri traveled to Italy this summer and went swimming in the Mediterranean Sea. Her skin felt very dry after a long day of swimming. Why does her skin feels dry?
1 Answer
Water moved out of her skin cells by osmosis due to the hypertonic solution.
Explanation:
The Mediterranean sea has a higher solute (namely salt) concentration than Ms. Palmeri's skin cells, thus it is a hypertonic solution. Water will then move by osmosis across the plasma membrane from her cells to the outside. This occurs as the water is trying to achieve a dynamic equilibrium across the membrane, meaning both sides have the same concentration of solute.
As the solute itself cannot move across the membrane and the water can, the water will move from the area of high water potential (low solute concentration, skin cells) to the area of low water potential (high solute concentration, sea/outside). There will be net movement of water across the membrane until equilibrium is reached. This may not be achieved during the time she is swimming, but there will be loss of water from her skin cells, thus resulting in the dry feeling of the skin.
