noun
surface tension
SUR-fis TEN-shun
Surface tension (noun) means the force that makes the surface of a liquid behave like a stretched elastic skin, caused by the molecules at the surface pulling more strongly on each other than on the air above. Example: “Surface tension is what lets a pond skater walk on water.”
noun
1
The force that makes the surface of a liquid behave like a stretched elastic skin, caused by the molecules at the surface pulling more strongly on each other than on the air above.
"Surface tension is what lets a pond skater walk on water."
"Adding washing-up liquid lowers the surface tension so the water can spread into the fabric."
How to use surface tension
Learner’s notesIn plain EnglishThe skin-like pull on the top of a liquid that makes drops round and lets insects sit on water.
When to use it
Standard scientific term, familiar from school physics and chemistry.
Memory tip
It is measured as force per unit length, usually in newtons per metre; water's is unusually high at about 0.072 N/m at room temperature.
Easily confused with
Common pairings
high surface tension
reduce surface tension
break the surface tension
surface tension of water
Vocabulary Flow
Build your vocabulary from words like surface tension.
Vocabulary Flow serves the next word, and the next — meaning, pronunciation and an example each time. Practice at your level, or learn English in your own language.
Start vocabulary practice
Fill the gap
Can you complete this real example?
_____ is what lets a pond skater walk on water.
Synonyms
View more →
interfacial tension
Rhymes for surface tension
region
ablation
allusion
emulsion
ideation
novation
diffusion
elocution
extension
oxidation
perfusion
selection
See all rhymes for surface tension →
Frequently asked questions
What causes surface tension?
Molecules inside a liquid are pulled equally in every direction by their neighbours, but molecules at the surface have no neighbours above them. The unbalanced inward pull draws the surface tight and makes the liquid minimise its surface area, which is why free-falling droplets are round.
What is the difference between surface tension and viscosity?
Surface tension is about the liquid's surface resisting being stretched or broken; viscosity is about how much the liquid resists flowing internally. Water has high surface tension but low viscosity; oil is the reverse.
Why does soap reduce surface tension?
Soap and detergent molecules have a water-loving end and a water-hating end. They gather at the surface and wedge between the water molecules, weakening the attraction between them — which is why soapy water wets fabric and dirt instead of beading up.
What is the meaning of surface tension?
"surface tension" (noun) means the force that makes the surface of a liquid behave like a stretched elastic skin, caused by the molecules at the surface pulling more strongly on each other than on the air above.
