stokes' law: meaning, definition, pronunciation and examples

C1+
UK/stəʊks lɔː/US/stoʊks lɑː/

Technical/Scientific

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Quick answer

What does “stokes' law” mean?

A physical law describing the settling velocity of a small spherical particle in a viscous fluid under gravity.

Audio

Pronunciation

Definition

Meaning and Definition

A physical law describing the settling velocity of a small spherical particle in a viscous fluid under gravity.

A principle in fluid dynamics stating that the frictional force on a sphere moving through a viscous fluid is proportional to its radius, velocity, and the fluid's viscosity. It is foundational to understanding sedimentation, centrifugation, and aerosol behavior.

Dialectal Variation

British vs American Usage

Differences

No significant lexical differences. Both dialects use 'viscosity' and 'velocity'. Spelling of related terms may differ (e.g., 'behaviour' vs. 'behavior').

Connotations

Purely technical; no connotative differences.

Frequency

Identical frequency within relevant scientific/engineering contexts.

Grammar

How to Use “stokes' law” in a Sentence

Stokes' law governs [noun phrase][Noun phrase] is described by Stokes' lawApplying Stokes' law to [noun phrase]

Vocabulary

Collocations

strong
calculate usingderivation ofapplicability oflimitations ofaccording to
medium
valid forbased onequation forpredict with
weak
simplestandardclassicalfluid

Examples

Examples of “stokes' law” in a Sentence

adjective

British English

  • The Stokesian flow regime is assumed.

American English

  • The Stokesian flow regime is assumed.

Usage

Meaning in Context

Academic

Common in physics, chemical engineering, geology, and environmental science textbooks and papers to model particle dynamics.

Everyday

Virtually never used.

Technical

Essential for designing sedimentation tanks, analysing blood cells in plasma, measuring oil droplet fall, or calibrating viscometers.

Vocabulary

Synonyms of “stokes' law”

Strong

Stokes drag lawStokes' settling law

Neutral

Stokes's lawStokes law

Weak

settling velocity equation

Vocabulary

Antonyms of “stokes' law”

Newton's law of inertia (in this context, for non-viscous flow)

Watch out

Common Mistakes When Using “stokes' law”

  • Misplacing the apostrophe (Stoke's law).
  • Applying it to turbulent flow or large particles where it is invalid.
  • Confusing it with Stokes' theorem in mathematics.

FAQ

Frequently Asked Questions

Both are grammatically acceptable. 'Stokes' law' is more common in scientific literature, following the convention for classical possessive forms with ancient or historical names ending in 's'.

Key assumptions include: the particle is spherical and rigid, the fluid is homogeneous and infinite in extent, flow is laminar (very low Reynolds number), and there is no slip at the particle surface.

Yes, for very small particles (like fine dust or aerosols) moving slowly, where the Reynolds number is less than ~0.3. For larger particles or higher speeds, it becomes inaccurate.

Stokes' law (or Stokes drag law) relates to fluid dynamics. Stokes' theorem is a fundamental theorem in vector calculus relating a surface integral of a curl to a line integral. They are different concepts by the same scientist.

A physical law describing the settling velocity of a small spherical particle in a viscous fluid under gravity.

Stokes' law is usually technical/scientific in register.

Stokes' law: in British English it is pronounced /stəʊks lɔː/, and in American English it is pronounced /stoʊks lɑː/. Tap the audio buttons above to hear it.

Learning

Memory Aids

Mnemonic

Imagine Sir George STOKES poking (Stokes) a small ball in thick honey (viscous fluid); the slower it sinks, the more the law applies.

Conceptual Metaphor

FLUID RESISTANCE IS FRICTIONAL DRAG.

Practice

Quiz

Fill in the gap
According to , the drag force on a small sphere is proportional to its radius and velocity.
Multiple Choice

Stokes' law is most accurately applied in which scenario?