Therese Donatello (St Edwards School) 
reviewed the discussion of organic chemistry begun last time. 

• We reviewed the concept of isomers, which have the same chemical formula [composition] but alternative structural arrangements.
• We continued by considering why carbon makes four bonds with other organic compounds (and inorganic ones as well), correlating that with the concept of valence electrons and the periodic table.
• We then used "ball and stick" atomic/molecular model kits, using our knowledge of hydrogen and carbon, to make our own hydrocarbon molecular models.  We used diagrams given out by Therese as our guides.  The 3-dimensional (actual ball and stick) models looked different from the 2-dimensional diagrams on paper.  Isomers can be made by rearranging atoms/bonds without adding or taking away any atoms.
• We combined a model of the simplest alcohol, methanol, and then continued with ethanol, n-propanol, isopropanol, and acetic acid.
• There was extensive discussion about ethanol in water, alcoholic beverages, why different alcoholic beverages have a different taste, and how this fact is related to the other chemicals in the beverages.  We discussed analysis of the chemicals present in alcoholic beverages by gas chromatography, and conjectured about correlations of these other chemicals to taste.

Karlene Joseph (Lane Tech HS) Propagation of Sound 
when sound travels from one medium to another, the speed and quality of the sound change.  This fact was demonstrated by hitting a metal strip [about 3 cm ´ 30 cm ´ 1 mm] on a string. We first hit the strip with a pen while holding it, and then put the strip itself against our ear. In the latter case the sound is transmitted through the strip, as well as in the air; in the former case we hear it only through the air. The sounds were quite different for the two cases.

Ben Stark (IIT Biology)
showed us a model of glucose, an organic compound at the heart of the process of our metabolism.  In the biological world plants take in light energy, carbon dioxide C0₂, and water H₂0; and produce glucose C₆H₁₂O₆ through photosynthesis.  Oxygen is given off as a byproduct.  The net chemical reaction is something like the following

Oxygen and glucose combine within animals or fungi to produce energy, and carbon dioxide is given off as a byproduct.  This Oxygen - Carbon Dioxide Cycle requires both green plants and animals for its continuous operation.  Energy is stored in glucose in the detailed arrangement of the chemical bonds of the atoms of Carbon, Oxygen, and Hydrogen.

Notes taken by Ben Stark and Karlene Joseph