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Discovering Natural Fibres: Non-Newtonian Fluids

What are Non-Newtonian Fluids?

These are fluids with properties that differ from ordinary fluids such as water.

Stirring a thick gel of methylcellulose will make it act more like water. The higher the rate of stirring the runnier it becomes. Water does not change in this way when stirred.

What is a non-newtonian fluid? - from Wisegeek

Results of experiment - on non-newtonian fluids, from Michigan Tech - interesting images

The Cambridge Polymer Group Silly Putty "Egg" - .pdf document from The Cambridge Polymer Group(355.6kB)

Oobleck: A Non-Newtonian Fluid Video - Science demonstration (video), how to make and properties

A Closer Look: Mystery Substance - from Annanberg Media Learner.org

Getting Critical over Colloids - from Science Buddies

Lumpy Liquids and Squishy Solids - from Science is Fun

Quicksand

How Quicksand Works - from How Stuff Works

How to Get out of Quicksand - from Wiki How

Teen dug out by hand from quicksand pit - article in Sydney Morning Herald

An Investigation

Not all solutions give the same answers: An investigation of the properties of two kinds of solution.

  1. What happens when you slowly heat ice cubes to about 50C?
    • Does the same thing happen if you mix 2 gm salt with 100gm crushed ice?
    • If you have already done this in an earlier class, refer to your graphs
  2. What happens when you heat methylcellulose in water solutions?
    • Use equal volumes of 0.5%, 1% and 2% methylcellulose. (eg 0.5 gm solid in 100 ml water.)
    • How will you measure the temperature?
    • How high will you let the temperature rise?
    • How will you stir the solution?
    • How will you record your results?
    • How will you clean up afterwards?
  3. Carefully describe your conclusions, comparing water, salt solution and methylcellulose solution.
  4. Methylcellulose solutions are used in shampoos and bubble baths. Why?
  5. Knowing that methylcellulose has very long molecules with side chains that stick out, make up a theory to explain the behaviour of the solutions as you heated them. How do water molecules differ?

Extension
Consider the way water molecules stick together by hydrogen bonding. Do you need to modify your theory from part 5?



Viscosity of liquids

Viscosity Chart - from Research Equipment (London) Limited

Practical Considerations

Measuring Viscosity - from Discovery Education - general activity on making volcanoes with an extension activity related to viscosity

Viscosity and flow - From University of Bolton, UK

Viscosity - a Simple Viscometer, from Science Projects

Splat test for Viscosity - in Teachers' Resource Guide: The Science and Scientists behind the food, see pages 16-18, from Discovery Education (pdf 977.5kB) (This technique could be modified to compare viscosity of different concentrations of methylcellulose or the same concentration at different temperatures)

Logarithmic Graph Paper PDF Generator - allows semi-log paper to be printed


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