What Is the Weissenberg Effect in Non-Newtonian Fluids?

TL;DR

The Weissenberg Effect occurs when a spinning rod causes a non-Newtonian fluid, like slime, to travel upward along the rod. This phenomenon is due to the fluid's unique properties, such as viscoelasticity and shear thickening, allowing it to self-gear and climb. Visualizing this effect can be done through colorful slime experiments at home.

Transcript

DIANA: Thanks to Curiosity Stream for supporting PBS Digital Studios. Hey, I'm Diana. You're watching "Physics Girl," and a video that I really like to make is a bunch of different science experiments that you can try at home. So we bought all the materials for like six different experiments, which is a lot of milk in my fridge that says do not dri... Read More

Key Insights

• 🗺️ The Weissenberg Effect is a fascinating phenomenon where a spinning rod causes a non-Newtonian fluid to travel up the rod.
• ❓ Non-Newtonian fluids, like slime, have unique properties such as viscoelasticity and shear thickening, which contribute to the Weissenberg Effect.
• 😥 The Weissenberg Effect can be visualized by creating different colors of slime and using a spinning rod to draw the fluid up from the meeting point of the colors.
• 🅰️ Understanding the Weissenberg Effect helps to explore fluid dynamics and the behavior of different types of fluids.
• 🧑‍🏭 By experimenting with variations in the slime recipe and controlling factors like the amount of Borax and glue, the extent of the Weissenberg Effect can be observed and analyzed.
• 🤗 Science experiments like the Weissenberg Effect with non-Newtonian fluids provide an engaging and hands-on way to explore scientific concepts.
• 🧡 Curiosity Stream is a subscription streaming service offering a range of documentaries and nonfiction titles, including educational content related to physics and science.

Questions & Answers

Q: What is the Weissenberg Effect?

The Weissenberg Effect is an unusual behavior observed in fluids, where a spinning rod causes the fluid to travel up the rod. It occurs in non-Newtonian fluids with viscoelasticity and shear thickening properties.

Q: How does the Weissenberg Effect work?

When a fluid with viscoelasticity is spun, it creates tension that tightens around itself. This inward force pushes the inner fluid up, leading to the upward motion observed in the Weissenberg Effect.

Q: Can the Weissenberg Effect be observed with all fluids?

No, the Weissenberg Effect is specific to non-Newtonian fluids. Newtonian fluids, like water, do not display this behavior. The elasticity and shear thickening properties of non-Newtonian fluids, such as slime, are essential for the Weissenberg Effect to occur.

Q: How can the Weissenberg Effect be demonstrated at home?

To recreate the Weissenberg Effect, make a non-Newtonian fluid like slime using a mixture of water, PVA glue, Borax, and optional additives like food coloring. Spin a rod slowly in the slime to observe the upward motion.

Summary & Key Takeaways

• The Weissenberg Effect occurs when a thin rod is spun in a fluid with specific properties, causing the fluid to travel up the rod.

• This effect is observed in non-Newtonian fluids, such as slime, which have unique viscoelasticity and shear thickening properties.

• By creating different colors of slime and using a spinning rod, the fluid's movement and the Weissenberg Effect can be visualized.