The Science of Water Rolling Off Skin After Swimming

When a person gets out of a swimming pool, water droplets remain on their skin. These droplets are held in place by the cohesive forces between water molecules and the adhesive forces between water molecules and the skin. As a person moves, the gravitational force pulls the droplets down. But if the cohesive and adhesive forces are strong enough, the droplets will not fall off.

To break these forces and remove the droplets, the person can do the following:

Wipe their skin with a towel: The towel absorbs the water droplets, removing them from the skin.

Shake their body: The shaking motion generates centrifugal force, which throws the droplets off the skin.

Let gravity take its course: If the person remains still, gravity will eventually pull the droplets down.

As the person walks, the droplets may bounce off the skin but stick back on. This is due to the dynamic forces exerted on the droplets as the person moves. The skin is a hard and immovable surface, so when a droplet hits it, it bounces off without sticking.