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School project resolution

Discussion in 'Electronic Design' started by BZ, Oct 31, 2004.

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  1. BZ

    BZ Guest

    Hi everyone,

    Thanks for the kind and helpful answers to my questions last week.

    After about 12 hours of bumbling with wires and diodes, with
    resistors and switches, with solder and electrical tape and
    hot glue, the project is finally complete, and even works.

    My daughter's atom was Argon, with 18 protons, 18 electrons,
    and 22 neutrons. A 9V battery would only power three LED's at
    a time, and using AC was not an option, so we ended up buying
    a five year supply of batteries at Sam's and building 20
    identical circuits on the back of the foam board. We have 20
    9V batteries taped along the bottom of the back, and the wires
    are a mess of spaghetti like you've never seen. Somehow we
    managed to use about 75 feet of wire on the back of a single
    poster-board sized sign. The only thing messier than the
    wiring is the tape job holding the excess wires down. The
    back of this looks like it was built by a chimpanzee in a hurry.

    To make the connections we twisted the wires together tightly
    and taped them down, and the connections seem reliable. The
    only connections that we soldered were the battery leads,
    because the battery lead wires were so flimsy they would never
    hold without solder, and I didn't trust a wire nut on these.
    Although I'm an electronic design idiot, I've done a lot of
    soldering in the past, and am actually pretty good at the
    mechanics of getting a good solder joint. I didn't want to do
    200 solder joints if I could avoid it, and got away with doing
    only 40, with me holding the soldering iron and my daughter
    applying the solder. She's become quite adept at applying
    solder and at cutting and stripping wire. (We've already
    discussed her taping skills...)

    We ran into an expected problem with the nucleus, where we had
    40 diodes packed shoulder-to-shoulder in a 2" diameter circle.
    After making all the necessary connections, we tried taping
    down the naked diode leads layer-by-layer to prevent
    short-cicuits, but it kept shorting out anyway, and we had to
    pull up all the tape twice. Eventually we used hot glue to
    encapsulate and isolate the naked diode leads, and that worked
    like a charm.

    From the front it looks great -- a black foam board with 18
    green LED electrons in orbits drawn using silver Sharpie
    markers, with a random grouping of 22 red and 18 yellow LED's
    in the center for the nucleus. Each subatomic particle type
    has a rocker switch on the front to turn them on and off. The
    LED's aren't as bright being three in series as they are with
    only two, but they're fine. Because we have a total of 58
    LEd's, we do have a couple sets of two diodes in series, and
    you can tell from the front which ones they are. (Don't even
    think of trying to figure it out from the back!)

    My daughter now knows a lot of electronics for a sixth-grader
    -- in fact, thanks to this project I think she learned more
    electronics than chemistry during this chemistry unit. Her
    best friend in the class, meanwhile, is instead learning how
    hard it is to glue a colored marshmallow to a piece of poster
    board.

    If I had it all to do over again, I would try what Spehro and
    Chris both suggested, and do fewer circuits in parallel.
    Being a simple-minded sort, however, I went with the simplest
    circuit I could and just did the same thing over and over
    again. I'm sure it cost me more in time and in battery
    expenses and isn't as elegant as their solution (especially
    since with their designs I could have wired the LED's two in
    series instead of three and gotten brighter light), but it was
    probably better for my daughter's education to build the same
    simple circuit over and over. She can explain that circuit
    pretty well in case the teacher asks, and it will be evident
    that she learned a lot doing this.

    Thanks again for the help!
     
  2. Rich Grise

    Rich Grise Guest

    Confectioners' sugar, water, and cornstarch. ;-)

    Congrats on the Atom!

    Cheers!
    Rich
     
  3. CFoley1064

    CFoley1064 Guest

    Subject: School project resolution
    Congratulations, Super Dad. IMO, helping the kid with the science fair project
    is one of the most satisfying parts of being a parent.

    Remember, this is only part of the grade. Spend the time and effort to do a
    good writeup, and you'll be in good shape. If there's a judge interview, try
    quizzing her with practice questions. Judges always like contestants with
    knowledge and poise, and that comes with practice.

    Do us a favor, and let us know if she wins a prize.

    Good luck (which is the residue of hard work, so I'm sure you'll have it)
    Chris
     
  4. ... helping the kid with the science fair project
    Having being a judge at several science fairs I have to
    disagree.

    Science fair projects done with parental help are
    obvious, some being entirely the work of the parents
    with the poor child reduced to gofer.

    One extreme example: 10 year old with oscilloscope,
    6 ft. of 2" quartz tubing, signal generator, power
    amplifier ... not the foggiest idea of what it all
    means though he has a prepared song-and-dance from
    which he can not deviate. Who's kidding who?

    Do I give the grade to the father (an automatic F) or to
    the child (an incomplete/late)?

    If parental help is supplied it is the parent who should
    be reduced to gofer.

    It may be fun for the parent to 'help' with a science
    project but in talking with them the child seems to find
    it hell.

    If a parent treats the child as a vicariously
    entertaining fashion accessory then heaven help them both.
     
  5. BZ

    BZ Guest

    This was a class assignment, not a science fair project. It
    turned out to be way too much work for just a class project,
    but once she got the idea in her head of having light-up
    protons, neutrons, and electrons, we were stuck with it, even
    when the scope of the work kept expanding on us.
     
  6. BZ

    BZ Guest

    I have also been a science fair judge and have seen the full
    spectrum of parental "involvement." One third-grader's
    written report began, "Over the course of my studies of molds
    and fungi, I have noticed that..." (Two years later, now in
    fifth grade, this same child admitted that her parents did her
    entire history project for her the night before it was due,
    after she went to bed.)

    Judging science fair projects can be an uncomfortable mixture
    of science, diplomacy, and politics, in which the judge often
    walks away unsatisfied with the score he gives no matter what
    he does.

    Being sensitive to that, I tried to let my daughter do as much
    as she could, and made sure she understood the hows and whys
    of everything. Although the project looks very pretty from
    the front and is a horrible mess on the back, the concepts
    involved are all well within her understanding.
     
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