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

Carol Giles [Collins HS] Bread Mold, Continued
We examined the (hoped for) moldy bread from Carol Giles' presentation two weeks ago. They had been sitting in Ben's office for the last two weeks. All of the "experimental" slices did in fact grow mold, and every single control slice was without mold—a spectacular result!. As a class we found about a dozen different species of mold that we had picked up swabbing various areas in the classroom.

It was a beautiful phenomenological lesson, Carol!

Walter Kondratko [Steinmetz HS] Melting Points
A handout contained the following information:

MELTING POINT DETERMINATION

Introduction:
In chemistry the two major ways of determining a compound's identity are through chemical and physical properties. In this lab, the student will investigate the method of using a physical property (melting point) to determine the identity of some compounds.
Safety:
goggles and aprons.
Materials:
Compounds of various melting points, capillary tubes, MEL/TEMP apparatus for measuring temperatures, and thermometers.
Pre-lab:
1. Name two methods for determining a compound's identity.
2. Can a melting point analysis be used on a liquid compound? Explain.
Procedure:
1. Obtain a known sample of Vanillin and 2 unknown samples from your instructor (be sure to record the letter of the unknowns).
  Obtain three capillary tubes and fill them to a height of 2 mm with the samples).
2. Place the tubes into the MEL/TEMP apparatus. Start with a relatively low temperature setting (2 or 3) and slowly increase the temperature. Record the temperature at which each melts.
3. When all compounds have melted, turn off the MEL/TEMP.
4. Look at the master melting point list and decide which of the compounds on the data sheet has a melting point that matches your unknown compounds.

MASTER LIST OF POSSIBLE COMPOUNDS USED FOR MELTING POINTS

Compound	Melting Point
Lauric Acid	44 °C
Benzophenone	48 ° C
Urethane	50 ° C
Diphenylamine	53 ° C
4-Methyl benzophenone	56.5-56.7 °C
Biphenyl	60 °C
Stearic Acid	71 °C
Vanillin	82 °C
Ethyl-4 aminobenzoate	89 °C
O-anisic acid	99 ° C

Walter brought 6-8 sets of apparatus that let us measure the melting points of chemicals accurately and easily. The instruments have a port into which a thin capillary tube containing an unknown (solid) chemical is placed, and a microscope which looks in on a hole in the port so that we can see whether the material in the tube is solid or liquid. A thermometer simultaneously records the temperature in the port, so that the melting temperature can be determined. The experiment was a great success with measured melting points generally within about ± 4 °C of the accepted/standard values.

This was an excellent hands-on lesson! Thanks, Walter.

Brenda Daniel [Fuller Elementary School] The Human Body, Particularly the Skeleton (Handout)
Brenda passed around a handout describing the Foss Human Body Module, which was developed at the University of California, Berkeley and published by Delta Education. This handout contained sketches of the human skeleton entitled COUNTING BONES, BONE NAMES, MUSCLE NAMES, and MR. BONES A-C.

Brenda discussed the human skeleton, using X- rays as an example of how to view the skeleton. As an exercise we then taped our fingers together, and then attempted to do normal activities that require the use of our hands. We learned -- firsthand -- of the importance of independent use of all the digits in our fingers. Amazing and informative! Thanks, Brenda!

Notes taken by Benjamin Stark.