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Introduction to one of the four states of matter where particles can slip past one another and take the shape of their container

Atoms Practice
Practice Liquids
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What Would Newton Say?

What Would Newton Say?


Credit: United States Geological Survey
Source: http://commons.wikimedia.org/wiki/File:Mitch-_Casita_Mudslide.JPG
License: CC BY-NC 3.0

Liquified mud flows down a mountainside in Nicaragua. Mud is usually a solid. But under some conditions, mud may turn to a liquid state and flow downhill.

The Back Story

  • All fluids (liquids and gases) can flow, but they resist flowing to some degree. Some fluids resist more than others (think honey vs. water). Resistance to flowing is called viscosity.
  • Most fluids have more-or-less constant viscosity at a given temperature. Such fluids are called Newtonian fluids. That’s because they behave as first described by Isaac Newton in the 1600s.
  • A few fluids are non-Newtonian fluids. These fluids behave very strangely and their viscosity can change. Sometimes they act like liquids. Sometimes they act like solids.
  • Credit: Jason Eppink
    Source: https://www.flickr.com/photos/jasoneppink/1804624609
    License: CC BY-NC 3.0

    Oobleck is both a liquid and a solid [Figure2]


  • An example of a non-Newtonian fluid is oobleck, a cornstarch-and-water mixture you may have made in school or at home. It’s fun to play with oobleck because it runs through your fingers like a liquid but acts like a solid if you squeeze it. You can see some oobleck and learn how to make it by watching this video: http://www.scientificamerican.com/article.cfm?id=oobleck-bring-science-home

Can You Apply It?

Learn more about Newtonian and non-Newtonian fluids at the link below. Then answer the questions that follow.

  1. What is a non-Newtonian fluid?
  2. Besides oobleck and mud, what are some examples of non-Newtonian fluids?
  3. What are examples of forces that change the viscosity of non-Newtonian fluids?
  4. What happens when the stress is removed from a non-Newtonian fluid?
  5. Why might an earthquake cause a mudflow?
  6. Why would a non-Newtonian fluid be good for body armor?

Image Attributions

  1. [1]^ Credit: United States Geological Survey; Source: http://commons.wikimedia.org/wiki/File:Mitch-_Casita_Mudslide.JPG; License: CC BY-NC 3.0
  2. [2]^ Credit: Jason Eppink; Source: https://www.flickr.com/photos/jasoneppink/1804624609; License: CC BY-NC 3.0


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