Foundations of Physical ScienceWorkshop: Viscosity of Fluids

Viscosity of FluidsCPO Science

Key Questions What is viscosity?

How can viscosity be measured?

How does a molecule’s shape and size affect viscosity?

How does an increase in temperature affect viscosity?

OverviewDefine viscosity

Build a viscometer

Measure viscosity of various liquids

What is Viscosity?A measure of a material’s

resistance to flow Which substance here has a higher viscosity?

How can it be measured?

Viscometer Uses timer and

photogates to measure speed of object moving through a liquid

Indicates the liquid’s resistance to flow

Average Velocity After setting up Viscometer run three

trials using 10 cm for the distance traveled by the marble through the fluid

Use velocity from the three trials to get the average velocity of the marble

Repeat this process for each of the 5 substances

Which Liquid is LEAST Viscous?

Compare average velocities – What will differences in these values indicate about each substance?

What does a high velocity mean?

What does a low velocity mean?

Rank the fluids from least to most viscous

What about Viscosity vs.

Density?? Compare the viscosity rankings list with the density ranking list

Is there a relationship?

What do these two terms actually measure?

They seem to be loosely related, but there must be more to the story

Size and viscosity Which molecule would

be easier to pour from a bottle?

Which would experience more friction?

How does that affect viscosity?