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  • In this activity, students watch the Brainiac video Jon Tickle walks on custard on YouTube to learn more about non-Newtonian fluids at work. The activity includes a number of strategies to deepen student interaction with video content.

    Rights: The University of Waikato

    Oobleck

    A cornflour and water mixture – is a non-Newtonian fluid.

    By the end of this activity, students should be able to:

    • discuss the differences between Newtonian fluids (‘normal liquids’) and non-Newtonian fluids
    • explain the scientific meanings of stress1 and strain2 as they relate to fluids
    • discuss how non-Newtonian fluids change their viscosity3 or flow behaviour under stress
    • explain why Jon Tickle is able to walk on custard but not on water.

    Download the Word file (see link below) for:

    • background information for teachers
    • teacher instructions
    • student instructions.

    Related content

    Non-Newtonian fluids change their viscosity or flow behaviour under stress as explained in the article Non-Newtonian fluids.

    Videos are a useful media to demonstrate aspects that cannot be recreated in the classroom. The article Using videos in the classroom provides a number of strategies that assist students to become more actively involved with the video.

    Activity ideas

    Follow this with the activity Danger – quicksand!

    Useful links

    The YouTube video John Tickle walks on custard demonstrates the difference between a pool filled with water (a Newtonian fluid4) and a pool filled with cornflour-based custard (a non-Newtonian fluid5).

    1. stress: In mechanics, a force applied to a body.
      In ecology and physiology, a response to a stimulus, e.g. an environmental factor, that disturbs or interferes with the normal equilibrium.
    2. strain: In microbiology, a subtype of a species of microorganism.
    3. viscosity: The measure of resistance of a fluid to flow. Thick slow-flowing liquids have a high viscosity, thin fast-flowing liquids have a low viscosity.
    4. Newtonian fluid: A fluid that maintains constant flow rate regardless of the amount of stress applied.
    5. non-Newtonian fluid: A fluid that changes in flow rate depending on the amount of stress or length of time that stress is applied.
    Published 12 April 2010, Updated 15 February 2018 Referencing Hub articles
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        stress

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      2. In mechanics, a force applied to a body.
        In ecology and physiology, a response to a stimulus, e.g. an environmental factor, that disturbs or interferes with the normal equilibrium.

        Newtonian fluid

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      4. A fluid that maintains constant flow rate regardless of the amount of stress applied.

        strain

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      6. In microbiology, a subtype of a species of microorganism.

        non-Newtonian fluid

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      8. A fluid that changes in flow rate depending on the amount of stress or length of time that stress is applied.

        viscosity

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      10. The measure of resistance of a fluid to flow. Thick slow-flowing liquids have a high viscosity, thin fast-flowing liquids have a low viscosity.