8.4: Water

Viscosity

Viscosity is an internal property of a fluid that offers a level of resistance to flow.  Water offers little resistance to flow which means it flows relatively easily and allows substances or objects to flow through it without much resistance.  There are many ways that viscosity is measured.  These include:

• Using a spring to push a rod into fluid and seeing how fast the fluid passes through a hole
• Dropping a sphere shaped object (of known weight) into the fluid and calculating how long it takes the object to fall through the fluid to a certain depth

High Viscosity = High resistance to flow (doesn’t flow easily); objects cannot pass through it without a large amount of force.

Low Viscosity = Low resistance to flow (flows easily); objects are able to pass through fairly easily without a great deal of force.

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 Outcome: 8.4.2- Students learn to explain the following properties of water in terms of its intermolecular forces:

- surface tension

- viscosity

- boiling and melting points