Viscosity Converter
Understand flow. From Water to Honey.
Ball Drop Test
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Viscosity Converter: The Science of Flow
Why does water splash while honey oozes? The answer is Viscosity—the measure of a fluid's internal friction ("thickness").
Our Advanced Viscosity Converter bridges the gap between Dynamic (cP) and Kinematic (cSt) units. Featuring a real-time "Ball Drop" simulation based on Stokes' Law, it helps students and engineers visualize how different fluids resist motion.
Fluid Dynamics Tools
Ball Drop Test
Interactive physics engine. Watch how viscosity slows down a falling object (Stokes' Law).
Dynamic vs Kinematic
Convert between Absolute (Pa·s) and Flow (cSt) viscosity by inputting fluid density.
Fluid Presets
Instantly load values for Water, Olive Oil, Honey, and SAE Motor Oils.
Understanding Viscosity
1. Dynamic Viscosity (μ)
Imagine sandwiching a fluid between two plates and sliding the top plate. Dynamic viscosity measures the force required to maintain that movement.
Unit: Pascal-second (Pa·s) or Centipoise (cP).
2. Kinematic Viscosity (ν)
This measures how a fluid flows under the influence of gravity (its own weight). Highly dense fluids might have high dynamic viscosity ("thick") but low kinematic viscosity ("flows fast") because their weight pulls them down.
Unit: Stokes (St) or Centistokes (cSt).
Frequently Asked Questions
What is the difference between Dynamic and Kinematic Viscosity?
Dynamic Viscosity (Absolute) measures a fluid's internal resistance to flow—how hard you have to push it (e.g., stirring honey). Kinematic Viscosity measures how easily a fluid flows under gravity (e.g., pouring water). They are related by density: Kinematic = Dynamic / Density.
What is a Centipoise (cP)?
A Centipoise is the standard CGS unit for dynamic viscosity. It is convenient because water at 20°C has a viscosity of almost exactly 1 cP. Therefore, a fluid with 100 cP is roughly 100 times thicker than water.
Why does Honey get runny when heated?
As temperature increases, the molecules in a liquid move faster and slide past each other more easily, reducing internal friction. This is why motor oil (SAE) ratings are critical; oil must not become too thin in a hot engine.
How do I convert cP to cSt?
You need the fluid's density. The formula is: Centistokes (cSt) = Centipoise (cP) ÷ Density (g/cm³). For water (density ≈ 1), 1 cP = 1 cSt. For heavy oils (density < 1), cSt will be slightly higher than cP.
What is Stokes' Law?
Stokes' Law describes the drag force on a sphere moving through a viscous fluid. Our 'Ball Drop' visualizer uses this principle: the higher the viscosity, the slower the terminal velocity of the ball.
What is a Non-Newtonian fluid?
A fluid whose viscosity changes under stress. Ketchup is 'shear thinning' (it gets runnier when you shake it), while Cornstarch and water is 'shear thickening' (it acts like a solid when punched).