Topic 4 Flashcards
Viscosity
Viscosity- the measure of how fast a fluid will flow; thickness or thinness; resistance to flow
Viscosity is a property of all fluid( liquids and gases) whether they are a pure substance or a mixture
Viscous and Flow rate
Viscous- thick; thicker fluid is more viscous and has a higher viscosity
Flow rate- the time it takes for a fluid to flow from one place to another
Viscosity in Industries
- Viscosity in liquids is and important property that must be measured precisely in some industries
- Industries like cosmetics and mechanics and the paint industry and food manufacturing all measure the viscosity precisely
They need to make sure the fluids flow properly, dry quickly, and are the right consistency
They need to change viscosity of materials to mix them properly
Viscosity in Liquids
Even though all fluids flow, they flow at different rates
The cohesive forces in some fluids are stronger than in other fluids
Temp increase= less cohesive force
Temp decrease= more cohesive force
Therefore, In liquids when they are heated, viscosity lowers and when cooled, viscosity rises
Friction
Another way to describe viscosity is Resistance to flow
Resistance to flow creates internal friction
Internal friction reduces the ease of particles to flow past each other
4 things that affect viscosity in fluids
- Temperature
- Size of particle
- internal friction
- Particle shape
Viscosity in Gases
Gases flow differently than liquids
Gas particles are so far apart that their cohesive forces are really low.
This means that the type of particle is less important
As gases gain energy they collide more, meaning they flow slower
More temp= more internal friction= slow flow rate
Therefore as heat increases, viscosity increases and as heat decreases, viscosity decreases.
ONLY IN CONSTRICTED GASES
Viscosity and Fluidity
Viscosity is the resistance to flow and fluidity is the ability to flow
High fluidity = low viscosity
Low fluidity= high viscosity
