Tag: Science Friday

  • Are Cats a Fluid?

    Are Cats a Fluid?

    Are cats a fluid? It’s a question that has inspired many a meme. There are a few common definitions as to what makes a fluid. One is that a fluid changes its shape to that of its container. Another more technical definition is that a fluid deforms continuously under shear forces. But the real picture is messier than these seemingly simple definitions allow for. On the Improbable Research podcast, I tackle the question of whether cats are a solid or a fluid and what fluid dynamics–specifically, the subject of rheology–has to teach us about the topic. Give it a listen! (Original image credits: Huffington Postimgur; research credit: M. A. Fardin, pdf – article begins on page 16)

    Post-Thanksgiving bonus: Today is the traditional Science Friday broadcast of this year’s (abridged) Ig Nobel Prize ceremony. Check your local NPR station for broadcast times or listen to it on their website. You’ll hear me deliver a 24/7 lecture on the subject of “Fluid Dynamics” (and you may find me cropping up elsewhere, too). Alternatively, you can check out the full ceremony video on YouTube.

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    Flowing Uphill

    Science Friday takes an inside look at self-propelled Leidenfrost droplets like those we’ve featured previously. The Leidenfrost effect takes place when a liquid comes in contact with a surface much, much hotter than its boiling point. Part of the liquid is vaporized, creating a thin gas layer that both insulates the remaining liquid and causes it to move with very little friction. Over a flat surface, this underlying vapor will spread in any direction. But by covering the surface with ratchets, it’s possible to direct the vapor in a particular direction, which propels the droplet in the opposite direction. Check out the video and our previous posts for more! (Video credit: Science Friday; via io9 and submitted by Urs)