[LM_NET] ELEM: Dewey numbers for planets - questions

[Suzanne Ng <suzanne@WHATEXIT.COM>]

I'm preparing to do a Dewey lesson, with 4th grade, as they study the
planets. This is the first year I'm integrating library skills with the
classroom topics (don't ask!) , and teaching with the teacher present.
My idea was to show the students how the 523.4's are broken down
further, by hundredths place, into a number for each planet.  I've
figured out the numbers correspond to the planets' positions from the
sun.  I realize that Dewey created his system more than 100 years ago,
but am wondering two things, and hope someone can offer some insight.

Why does 523.44 (where Earth should be) contain some titles on
asteroids (at first I thought of the Asteroid belt, but then found
other books on asteroids in 523.5) instead of Earth?

  Why do Neptune and Pluto share a number. ? Why isn't Neptune 523.48
and Pluto 523.49 ?

  I understand that 523.44 would be huge, so Earth as a planet was put
in 525 (but my students aren't going to buy that explanation) .

FWIW, I used Sunlink and Titlewave as reference points for getting the
DDC numbers. The online listings of DDC that I have found, do not break
down past the decimal point.

  Thanks for any help or insight anyone can offer!
*********************************************************
Suzanne Ng, Librarian
South Mountain Elem. School
South Orange, NJ 07079
email: suzanne at whatexit dot com
http://www.southmountain.somsd.k12.nj.us
*********************************************************

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