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The History of the Grounded Electron - Help please

  1. May 30, 2013 #1
    So my physics teacher assigned us with this task (title). Basically our objective is to compose a short narrative written in the pov of an electron. The story has to center around places that an electron visits, that once lived in an atom wool, and ultimately entered the ground. The electron has to visit at least three different locations (eg a balloon, glass rod, electroscope, van de graaf, a person etc.) during it`s journey from the wool to the ground. For each location, I must identify, describe and explain the process is goes through (friction, induction etc.) which was caused by that location.

    So basically I want to ask you guys for help on making this a great assignment.
    Any examples you can think of that would be great for locations for this electron to visit, where should it enter first, what happens there, etc. I finally have a solid physics grade and I want to keep it there, so any help would be greatly appreciated!

    Thanks in advance ! :)

    ps. I`m aware I can`t just take your guys`answers, I don`t plan on it, I just want a variety of ideas that I can include in my story!
     
  2. jcsd
  3. May 30, 2013 #2

    berkeman

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    Welcome to the PF.

    You are quite right that we cannot do you assignment for you. You must do the bulk of the work (that's in the Rules link under Site Info at the top of the page). I will give you a hint to start you off -- look up how "static electricity" works. Please do some reading about that subject, and then post your ideas so far for your paper. After that we may be able to offer another hint or two for other things you should read about...
     
  4. May 30, 2013 #3
    So far I'm thinking;

    >a loose negative electron within the nucleus of an atom on a woolen shirt that is going crazy because it needs to get to the ground
    >shirt is taken off, and thrown onto dog, loose electron breaks free and transfers into new nucleus of: dog which is more positively charged
    >dog's fur becomes more negatively charged
    >dog walks across carpet, becomes more charged negatively
    >dog runs outside, kid pets dog, kid gets a shock
    >electron is transferred through kid and into the ground

    Does this sound good? Clearly I need to add more physics related terms in this, but do all of my situations work?
     
  5. May 30, 2013 #4

    berkeman

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    Not bad, and fairly creative. But, electrons do not exist in the "nucleus" of an atom. Look up the terms "valence band" and "conduction band" of solids. And be sure to do the reading about static electricity that I mentioned.

    After you look up those terms, show us how you are going to modify what you have written, to correspond better with the physics of what is going on.
     
  6. May 30, 2013 #5
    Just to make sure I'm clear on how to relate valence band and conduction band into my paper:

    The wool is an insulator, therefore the conduction band is higher than the valence band, so it takes a impractical amount of energy for the electron to come non-local, correct? But if the wool shirt was thrown onto the dog, the dog may receive a little shock due to the quick jump of electrons into now the dogs fur coat, which is now negatively charged. I'm a little confused as to how the electron becomes free of the atom and transferred into the new one.
     
  7. May 30, 2013 #6

    berkeman

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    Did you read the wikipedia page on static electricity that I suggested? It is pretty clear about how charge is transferred, and in which direction (which material to which material):

    http://en.wikipedia.org/wiki/Static_electricity

    If you have specific questions about the article, post a quote from it and ask your question about the quote.
     
  8. May 30, 2013 #7
    Okay, I have read through the links as well as a couple either. Here is my new approach:

    >person wearing wool socks walking across carpet in socks, socks are becoming more negatively charged due to friction (triboelectric effect)
    >weakly bound electron is currently sitting loosely in outer shell of an atom within a sock
    >person walks by dog and gives it a rub with his/her foot on the back
    >during this contact, adhesion occurs, charges move from the wool to the dogs fur to create electrochemical potential, including the electron
    >the dog is now more negatively charged than positively
    >my electron is now within the outer shell of an atom located on the dogs fur

    Sounding good so far?
     
  9. May 30, 2013 #8

    berkeman

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    Much better! I would add the word "valence" to the outer shell of the atom, to make it clear that the material is an insulator. Keep it up!
     
  10. May 30, 2013 #9
    Great! Thank you for hanging along this far, I really appreciate it.

    Continued:

    >dog walks along carpet, more friction = more negative charges being added to atoms
    >dog is let outside
    >child is playing which the dog walks up to to be pet
    >when child pets, electric discharge occurs, creating a shock felt by both the dog and the child
    >electron is transferred from it's valence shell from an atom on the dogs fur to another valence shell of an atom on the child

    Any ideas on a good way to end this?
     
  11. May 30, 2013 #10
    What if I said the child was holding on to a grounded pole for leverage while putting it's shoe on, and the dog rubbed against it, completing the circuit between negatively charged dog fur and the neutral child, then the electron would see the child as a pathway to the ground where it would then travel to?
     
  12. May 30, 2013 #11

    berkeman

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    Yeah, like a water pipe that goes through the concrete sidewalk by the house. Concrete is an insulator, but the water pipe will go down into dirt under the concrete, which is a very conductive path to ground. Everything before that was an insulator, so the static charge transfers are as you described them.

    Good job. That wikipedia article was pretty useful, eh? :smile:


    EDIT -- BTW, it would be cool for you to list that article as a reference to your paper. I think that will win you some points with the instructor.
     
  13. May 30, 2013 #12
    haha, you are right. I'm just one of those guys who loves to have everything verified or looked over by others before actually starting final copies. Better to have the output of two than one, right?

    So my final summary is going to look like this:

    >person wearing wool socks walking across carpet in socks, socks are becoming more negatively charged due to friction (triboelectric effect)
    >weakly bound electron is currently sitting loosely in outer shell of an atom within a sock
    >person walks by dog and gives it a rub with his/her foot on the back
    >during this contact, adhesion occurs, charges move from the wool to the dogs fur to create electrochemical potential, including the electron
    >the dog is now more negatively charged than positively
    >my electron is now within the outer shell of an atom located on the dogs fur
    >dog walks along carpet, more friction = more negative charges being added to atoms
    >dog is let outside
    >dog notices child, who is pumping water from an iron water pump (lol)
    >dog rubs against child, circuit between child and dog is complete which creates a electric discharge, shocks both
    >electron(s) from dog passes through child and into the pump and into the ground in less than a microsecond
    >end
     
  14. May 30, 2013 #13
    If there are any more physics-related terms you feel I could use to snag some extra points, feel free to point out a few :)
     
  15. May 30, 2013 #14

    berkeman

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    I'd still mention the word "valence" when referring to the outer electron shell of insultors. You could just mention it parenthetically if you want -- "outer (valence) shell"...
     
  16. May 30, 2013 #15
    Yes I will definitely include that. Would you be interested in reading my rough copy once completed If I enter it in this thread in a little bit?
     
  17. May 31, 2013 #16

    CWatters

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    How about the dog goes to find his master who is busy filling up the lawn mower with gas :-)
     
  18. May 31, 2013 #17

    berkeman

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    :rofl:
     
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