From: Coco Ballantyne (cocoballantyne@hotmail.com)
Date: Wed Feb 07 2001 - 13:26:28 PST
From: "Coco Ballantyne" <cocoballantyne@hotmail.com> Subject: Re: pinhole Re: Pasta/Toothpick Bridges Date: Wed, 07 Feb 2001 13:26:28 -0800 Message-ID: <F74SByh133tYwlib4g300003ebc@hotmail.com>
Thank you so much, Al! Here's the address:
Coco Ballantyne
Eastside College Preparatory School
2101 Pulgas Ave
East Palo Alto, 94303
>
>The Bridge Project is a great way to have the students do research and
>build
>a demonstration of their resolution of forces model. I had my students do
>a
>term paper on bridges then make a model of their own design. Originally
>these were done with various types of pastas from angelhair to spaghetti to
>linguini. The San Francisco high school where I was teaching had a mouse
>and
>rat problem so bridges left overnight got eaten. We switched to toothpicks
>and used hot glue guns. The hot glue allows a joint to be made in minutes
>whereas the glue, Elmers, takes hours to dry. The students loved the end
>of
>the project when the bridges were destructively tested. It was not
>uncommon
>for a bridge to hold 10,000 times its own weight. The almost instantaneous
>collapse of a bridge is a great demonstration of elastic limit. We used a
>$6
>dollar dial gauge from Harbor Freight Tools to show bridge deformation as
>mass was placed on the structure. If you are good with construction you
>can
>make a standard "gap" with wood blocks that the bridge must span and have a
>set of rules the students must use. e.g. No gluing pasta/toothpicks into
>a
>solid block as they may only have glue applied within 10 mm of the ends.
>
>I lifted the project and expanded the idea from my son's 8th grade science
>teacher at Sinaloa Middle School in Novato, California. Where she got it I
>do not know but it sounded like an Exploratorium snack. I may still have
>some of the lesson plans and handouts I did for my students. List the
>complete address of your school and I'll send them to you.
>
>Al Sefl
>Retired but still teaching Physics...........
>
>---------------------------------------------------------------------------
>
>To unsubscribe from pinhole, send an email to requests@exploratorium.edu
>with the words 'unsubscribe pinhole' (without the quotes) in the SUBJECT
>of the email.
>
>To subscribe to the digest and only get 1 combined message a day, send an
>email to requests@exploratorium.edu with the words 'subscribe digest
>pinhole' (without the quotes) in the SUBJECT of the email.
>---------------------------------------------------------------------------
>
>
_________________________________________________________________
Get your FREE download of MSN Explorer at http://explorer.msn.com
This archive was generated by hypermail 2b29 : Tue Oct 16 2001 - 12:22:15 PDT