From rkellogg@comcast.net Mon Jul 11 07:03:58 2005 Date: Sat, 9 Jul 2005 22:15:27 -0400 From: Robert Kellogg To: Walter Sanford , Mac Oglesby Cc: Fred Sawyer Subject: Re: It's About Time - Sundials // Moving On [ The following text is in the "iso-8859-1" character set. ] [ Your display is set for the "US-ASCII" character set. ] [ Some characters may be displayed incorrectly. ] Walter, Here's my ordered list ... not sure of the weighting of importance as we go down the list: Students are to make a horizontal or vertical (south facing) dial for a specific location (latitude/longitude) a. the dial shall have hour lines from 5am until 7pm b. the dial may be "classic" to mark local solar noon, or c. the dial may be "modern" with extra credit for using correction for time zone longitude (hopefully, coaches can explain how to twist the dial lines for longitude difference from the time zone longitude. As you know, this is not a simple rotation... each dial line is differenced). d. the dial may be plane or artistic. In any case, the dial shall be drawn neatly and as accurately as possible. e. extra credit is given for a dial that uses a thick (1/2 inch or more) gnomon. The gnomon may be made from wood, folded paper, etc. The dial itself must accurately show hour lines for the gnomon. 1. Are the dial lines clean and accurate (as a Brit might say, "spot on") for the stated latitude? 2. If longitude correction is used, is it done properly? 3. Does the gnomon share the same stated latitude angle? 4. Does the gnomon foot meet the 6-6 line for a classic dial (or appropriate time for a "modern" dial)? 5. If a thick gnomon is used, are the 5 and 7 hour liens drawn correctly 6. Are the rest of the lines drawn neatly? 7. Are their numbers? If so, do they match the appropriate hour lines? 8. Are their additional time marks? (e.g. half hour, quarter hour, 5 or 10 minutes). Are they neatly drawn? 9. Are their unique features? (e.g. nodus notch on the style and corresponding solstice and equinoctial lines?) (Note: we need a way for students to easily create these lines and and even better way for judges to evaluate the lines to assess correctness.) 10. Is there an accompanying E.O.T. (extra points if it is done accurately for the classic dial's intended Longitude). Is there a correct explanation of how to use the EOT? Regards Bob ----- Original Message ----- From: "Walter Sanford" To: "Mac Oglesby" Cc: "Fred Sawyer" ; "Robert Kellogg" Sent: 07/09/2005 2:16 PM Subject: Re: It's About Time - Sundials // Moving On > Gentlemen, > > Now that we've cleared the air, here is the next challenge: Define the > *exact* criteria you would use to judge a sundial; if possible, please > list the criteria in order of importance. Also, please let me know whether > some items should be weighted more than others. I will compile & try to > synthesize your lists into a single scoring rubric that we agree is > on-target and fair, while not being too nit-picky. That's a tall order! > > When grading student work, sometimes I use a wholistic approach rather > than grading every item. In this case, a wholistic rubric may not be > practical (but I'm open to suggestion). My worst fear is that all of the > sundials will turn out to be of equal quality (which could be poor), in > which case I think we need a well-defined scoring rubric that will enable > us to differentiate among sundials of comparable quality (good, bad, or > in-between). Make sense? > > ================================================================= > Walter Sanford, Director Carl Sandburg Middle School > Center for Sky Awareness 8428 Fort Hunt Road > Sandburg Planetarium Alexandria, VA 22308 > Fairfax County Public Schools Work: 703-799-6169 -6197 (fax) > E-mail: wsanford@wsanford.com Home: 703-765-9392 > AMS Project ATMOSPHERE Atmospheric Education Resource Agent & > Water in the Earth System (WES) Resource Teacher > SCSA, Geosystems, & Camp T-Equity - URL: http://www.wsanford.com/ > ================================================================= > >