Sarah, aged 3, Learns About Soap

Posted on January 4, 2007  Comments (9)

A Dialogue with Sarah, aged 3: in which it is shown that if your dad is a chemistry professor, asking “why” can be dangerous [the broken link was removed] by Stephen McNeil.

DAD: Why does the soap grab the dirt?
DAD: Because soap is a surfactant.
DAD: Why is soap a surfactant?
DAD: That is an EXCELLENT question. Soap is a surfactant because it forms water-soluble micelles that trap the otherwise insoluble dirt and oil particles.

Great. I remember such discussions with Dad (Chemical Engineering professor). The only danger I saw was him getting tied of -why? (when I was older). And sometimes giving me answers the teacher didn’t like (a way of doing math problems that wasn’t the way my teacher was teaching).

Related: Illusion of Explanatory DepthExcellence in K-12 Mathematics and Science TeachingWhat Kids can LearnScience for Kids

DAD: Why is oxygen more electronegative than carbon and hydrogen?


DAD: That’s complicated. There are different answers to that question, depending on whether you’re talking about the Pauling or Mulliken electronegativity scales. The Pauling scale is based on homo- versus heteronuclear bond strength differences, while the Mulliken scale is based on the atomic properties of electron affinity and ionization energy. But it really all comes down to effective nuclear charge. The valence electrons in an oxygen atom have a lower energy than those of a carbon atom, and electrons shared between them are held more tightly to the oxygen, because electrons in an oxygen atom experience a greater nuclear charge and therefore a stronger attraction to the atomic nucleus! Cool, huh?


SARAH: I don’t get it.

DAD: That’s OK. Neither do most of my students.

Related: Why Use Designed Factorial Experiments? – “I said, but you explained that to me and I am just a kid, how can you be teaching adults that? Didn’t they learn it in school?”

9 Responses to “Sarah, aged 3, Learns About Soap”

  1. Curious Cat Science and Engineering Blog » How Does That Happen? Science Provides the Answer
    September 20th, 2007 @ 1:40 pm

    “The rough surface of the bricks, particularly around the edges and corners, provides nucleation sites for dissolved gases. Gas molecules collect preferentially around the edges of the bricks, eventually producing bubbles…”

  2. Curious Cat: Now for Something Completely Different
    July 14th, 2008 @ 12:02 pm

    I think we might have another young engineering on our hands, with the right training 🙂 She knows what she wants and isn’t stymied by constraints that would probably blind most of us to the possibilities…

  3. Curious Cat » Students at Powhatan Engineering Camp
    July 31st, 2008 @ 8:44 am

    Powhatan County Schools engineering camp spent eight days doing hands-on activities like building model amusement park rides and suspension bridges, and taking field trips to see engineering in action…

  4. Curious Cat Science and Engineering Blog » More Mysterious Space Phenomenon
    September 26th, 2008 @ 8:36 am

    […] learning as curiosity leads us to seek better understanding. On a small scale this can mean a person learning more about knowledge already understood by others. But it also means the scientific community facing new […]

  5. Curious Cat Engineering: StoryCorps: Passion for Mechanical Engineering
    December 13th, 2008 @ 11:41 pm

    When her father asked what had happened, his daughter answered, “Oh, I took it apart. Daddy fix.”

  6. Grace
    June 7th, 2009 @ 1:07 am

    Amazing how she can relate to all these science stuff at a very young age! I love conversations with children!

    * Thanks for dropping by my blog earlier this week! *

  7. Naturally Curious Children » Curious Cat Engineering and Science Blog
    January 1st, 2011 @ 7:00 pm

    I write this blog because when I was a kid I was curious and had parents who gave me enough interesting answers and interesting resources to build on that curiosity…

  8. Encouraging Curiosity in Kids » Curious Cat Science and Engineering Blog
    October 28th, 2011 @ 5:30 am

    […] is fun as a kid if your parent is a scientist or engineer (my father was an engineering […]

  9. Michelle Gaboya
    February 20th, 2014 @ 7:40 am

    So cute! The inquisitive minds of children 🙂 We should pay them more deserved attention!

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