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[The Science of Oobleck: Understanding Non-Newtonian Fluids]-[Oobleck! Make Up Your Mind!]

Wow in the World · B1 · 2020-05-11

Preschool Enlightenment
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📋 Summary

The Science of Oobleck: Understanding Non-Newtonian Fluids

In this episode of Wow in the World, hosts Mindy and Guy Raz explore the fascinating physical properties of matter, specifically focusing on a unique substance known as oobleck. By transforming a swimming pool into a giant experiment, the hosts demonstrate how certain substances defy the conventional classifications of matter.

Defining Matter and the Role of Viscosity

Traditionally, matter is categorized into three primary states: solids, liquids, and gases. Guy Raz explains that most substances, like water, are considered Newtonian fluids. A Newtonian fluid maintains a constant viscosity—a measure of a fluid's thickness or resistance to flow—regardless of the physical force applied to it. Whether you stir it, jump into it, or pour it, water consistently behaves like a thin liquid because its viscosity does not change.

The Nature of Non-Newtonian Fluids

In contrast, oobleck is classified as a non-Newtonian fluid. This substance acts as a "scientific trickster" because it does not play by the standard rules of matter. Depending on the amount of force applied, oobleck can transition between the properties of a liquid and a solid.

When at rest or subjected to slow movement, the mixture of cornstarch and water behaves like a viscous, creamy liquid. However, when sudden force or pressure is applied, the material thickens rapidly, transforming into a solid. This behavior is what makes oobleck so unpredictable and scientifically intriguing.

The Particle Physics Behind the Phenomenon

The transformation is driven by the microscopic nature of cornstarch. According to research from engineers at MIT, cornstarch particles are extremely small—roughly 100 times smaller than a grain of sand. At this scale, the particles are heavily influenced by electric charges.

When moving slowly, these electric charges cause the particles to repel one another, allowing them to slide past each other like a fluid. However, when forceful pressure is applied, the particles are pushed together so quickly that they cannot repel each other. They make contact, creating friction that causes them to bunch together, effectively turning the mixture into a solid. Once the force is removed, the particles return to their repulsive state, and the substance reverts to its liquid form.

Real-World Applications

Beyond the playful experiments in the swimming pool, this research has practical implications. Engineers are studying these materials to see if they could be used to address everyday infrastructure problems, such as repairing potholes. The ability of a material to flow into a crack and then harden under the force of passing traffic suggests that non-Newtonian fluids could provide innovative solutions for road maintenance.

This episode highlights how curiosity and experimentation—even when involving a pool filled with 220,000 pounds of cornstarch—can lead to a deeper understanding of the complex physical world. By observing how force dictates the state of matter, we gain insight into the hidden mechanics of the substances that surround us.

🎯Key Sentences

1
I'll be the judge of that.
2
You never asked.
3
I'm stuck in the goo.
4
Well, to be fair, you're always full of surprises.
5
Wait, what?
Expand All

📝Key Phrases

1
music to your ears
2
get on with the show
3
full of surprises
4
speak up
5
play by the rules
Expand All

📖 Transcript

Grownups, Wondery Plus subscribers can listen to Wow in the World early and ad-free right now.
Join Wondery Plus in the Wondery app or Wondery Kids Plus on Apple Podcasts.
Hey, Wowzer fans, Mindy here.
And before we start the show, I gotta let you know that this November, with a special new episode featuring our friends at Circle Round and Terrestrials on Radiolab for Kids,
And don't miss when Elmo from Sesame Street stops by Wow in the World to make us all belly laugh on November 24th.
Oh, but that's not all, Reg.

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