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Surface Tension Explained

Surface tension is the property of liquids whereby they behave as if covered by a thin elastic skin. This occurs because molecules at the liquid surface ex

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TL;DR: Surface tension is the property of liquids whereby they behave as if covered by a thin elastic skin. This occurs because molecules at the liquid surfa…

Written & reviewed by the Syllab.in Academic Team (CBSE/NCERT subject experts) · Updated Jul 23, 2026

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Surface Tension: Surface tension is the property of liquids whereby they behave as if covered by a thin elastic skin. This occurs because molecules at the liquid surface ex

Surface Tension Explained Simply

Surface tension is the property of liquids whereby they behave as if covered by a thin elastic skin. This occurs because molecules at the liquid surface ex This is a key Physics concept for 11.

Frequently Asked Questions

Why is water's surface tension so much higher than most liquids?

Water molecules form strong hydrogen bonds with each other. These hydrogen bonds create very strong intermolecular attractive forces, resulting in high surface tension (~72 mN/m at 20°C). Most other liquids lack such strong intermolecular forces.

How does adding soap reduce surface tension of water?

Soap molecules have both hydrophilic (water-loving) and hydrophobic (oil-loving) parts. They accumulate at the water surface with hydrophobic parts pointing outward, disrupting the regular hydrogen bond network of water molecules. This reduces the net inward force and thus the surface tension.

Why do insects like water striders not sink even though they are denser than water?

Water striders have water-repellent (hydrophobic) legs that do not break the water surface. The weight of the insect creates dimples in the water surface but does not penetrate it. The surface tension of water is strong enough to support the insect's weight distributed over the leg area.

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