High School Biology-Chemistry SMILE Meeting
23 March 2004
Notes Prepared by Porter Johnson

Don Kanner  [Lane Tech HS, Physics]         Acid Reflux
[a visitor from the Math-Physics SMILE class] spoke about his recent diagnosis for this condition at Northwestern Memorial Hospital.  The acid reflux condition, more properly described as esophageal reflux, involves leakage of stomach acid back into the esophagus, and can cause severe damage to the esophagus.  Don's physician does not agree with the commonly prescribed anti-acid prescription for reflux disease.  He said, instead, that people who have heartburn should eat at least 2 - 3 hours before bedtime.  Snacks just before bedtime stimulate the production of stomach acid, which has a tendency to "roll down" into the esophagus when you lie down in bed.  

Thanks for the tip; we feel better already, Don!

Wanda Pitts  [Douglas School]         Spinners
began this lesson on Physical Chemistry by asking us about inertia.  We pointed out that inertia is the tendency of an object to resist a change in its motion.  Next she placed a raw egg on the table, and let it sit for several seconds.  Then, she gave the egg a gentle spin, and measured the time for it to come to rest.  We repeated this experiment for several trials with the raw egg.  Then, we repeated the experiment with a boiled egg.  Here are some data obtained for the two cases:

Case Trial 1 Trial 2 Trial 3 Trial 4 Average
raw egg   8 sec   7 sec   4 sec   4 sec 5.25 sec
boiled egg 13 sec 14 sec 15 sec 12 sec 13.5 sec
Despite the fact that the two eggs have about the same mass, the raw egg dissipates energy of rotation more quickly than the boiled egg. There must be more "sloshing around" inside the raw egg, which uses up some of its energy, so that it will not remain in rotation for as long a time as the boiled egg.

Wonderful, Wanda!

Barbara Lorde  [Attucks School]         The Muscular-Skeletal Systems of Humans
began this Biology lesson by having us make various motions with our bodies, paying special attention to changes in the positions of vertebrae in our backs.  We made use of a full-size plastic model of the human skeleton, obtained from a Biology Laboratory at IIT, to illustrate the spinal column, the spinal cord, and the function of the arm.

Barbara then showed us how to make a model of our spinal system, using a shoe string to represent the spinal cord, and sewing thread spools  to represent vertebrae.  We also used wooden dowels and rubber bands to make models of the upper arm, including the humerus, radius, ulna, and the elbow joint.  The models were extremely instructive!

So that's how we're put together.  Very nice, Barbara!

Carol Giles [Collins HS]         Defining, Identifying, and Interpreting a Pedigree
began this Genetics lesson by reviewing the ideas behind a pedigree --- a portrait of the genetic (ancestral) history of a trait in a family.  In particular, she focused attention upon particular hereditary traits, such as D:  detached earlobe versus a: attached earlobe. The D: detached earlobe trait is dominant over the a: attached earlobe trait.  We analyzed the pedigrees of four individuals, indicating the genotypes for each ancestor, and the modes of propagation.

Note that 75% of our population have detached earlobes, whereas 25% have attached earlobes.  See the website Comparing Traits:   http://faculty.southwest.tn.edu/jiwilliams/Human_Traits.htm.  For additional examples see also:  http://www.fi.edu/guide/knox/Traits/traitsexamples.pdf.  

Very interesting stuff, Carol!

Notes taken by Benjamin Stark.