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### College Physics (Urone)

Book edition 1st Edition
Author(s) Paul Peter Urone
Pages 1272 pages
ISBN 9781938168000

# Water beads up on an oily sunbather, but not on her neighbour, whose skin is not oiled. Explain in terms of cohesive and adhesive forces.

Water do not bead up as the skin is not oily, the adhesive force is more between skin and water molecule.

See the step by step solution

## Step 1: Conceptual Introduction

Fluid statics, often known as hydrostatics, is a branch of fluid mechanics that investigates the state of balance of floating and submerged body, as well as the pressure in a fluid, or imposed by a fluid, on an immersed body.

## Step2: Define the Cohesive and Adhesive Force

Cohesive forces are attractive forces between molecules of the same sort. Because cohesive forces hold the molecules together, liquids may be held in open containers. Adhesive forces are the attractive forces that exist between molecules of various sorts.

Liquid drips, for example, adhere to glass panes as a result of such pressures.

We will look at the effects of cohesive and adhesive forces in liquids in this section.

## Step 3: Why water beads up?

Water molecules bind to one another due to cohesive force. Because oil repels water molecules, it is impossible for water to reach the skin's surface.Because the adhesive force between oil and water is so low, water molecules stay together to form beads owing to the high cohesive force.

The adhesive force between water molecules is almost equal on dry skin, therefore water spreads out on the skin and does not bead up.

Hence, the skin is not greasy, water does not bead up, and the adhesive force between the skin and the water molecule is greater, therefore water spreads.