High School Biology-Chemistry SMILE Meeting
09 October 2001
Notes Prepared by Porter Johnson

Barbara Pawela (May School, retired)
Barbara showed some plants just taken from her yard [or "garden", if you speak British], as well as those obtained elsewhere  We investigated the structure, life cycle, and process of reproduction for the following plants:

We examined all the specimens --- roots, leaves, fruits, seeds, etc, and discussed the role of each part. For example, the seeds make reproduction possible.

To complement the discussion of the specimens, Barbara distributed a handout, What Do Root Hairs Look Like?

Barbara also showed us tomatoes, walnuts, and eggplants, as well as seeds of dried flowers --- all taken from her garden as additional specimens.

Barbara also handed out bean seeds to be grown in the zip-lock bags.  The marigold and pumpkin seeds should be placed in potting soil to make the plants.  We will wait and watch for them to grow!

Marva Anyanwu (Lincoln Park HS) The Tensile Strength of Spaghetti (handout)
The handout explained that "raw spaghetti" is a surprisingly strong material --- before you cook it.  Spaghetti***  is categorized by thickness of the strands.  In particular, angel hair spaghetti is thin, and "regular spaghetti" is described as #8 on the boxes.

Tensile strength  is measured by stretching an object until it breaks.  A rope used in a tug-of-war is under tensionCompression occurs when forces push into an object. For example, a pillar supporting a building is subject to compression.  When a long, thin object is supported horizontally at its ends and pushed down at the middle, the top edge is under compression and the bottom edge is under tension.
To measure the tensile (tension) strength of a length of spaghetti, you can bend it by adding weight to its center until it breaks.  Support opposite ends of a single piece of spaghetti, allowing 2 cm of each end to rest on the support.  Hold those ends in place so that the spaghetti cannot move.

We worked in groups, using both "thick" and "thin" spaghetti. We placed a spaghetti strand with  the ends on two desks, and over the strand we looped a piece of string that was tied to a Styrofoam™ cup.  We added weights to the cup until the spaghetti strand broke, and recorded the data.  We drew the following conclusions:

Marva mentioned that she was particularly interested in the SMILE Biology-Chemistry class. She hadn't thought of spaghetti as being strong, and was surprised by the experiments.

*** The word spaghetti means little strings in Italian and is always plural. The rumor that spaghetti plants grow in long thin patches between lanes on interstate highways is false. After all, spaghetti requires a hot, dark environment for proper development.

Notes taken by Ben Stark