The Winter of Tomis in 8 A.D.

Discussion
In 8 A.D. Augustus Caesar exiled the Roman poet Ovid(Publius Ovidius Nasso 43 B.C. - 17 A.D.) to the remote Black Sea town of Tomis (modern Constanta, Romania). Not only was Ovid isolated from the political, social, and intellectual center of his world, but he also had to endure a climate much harsher than that of Rome. To lament his exile, he wrote the Tristia, poems that detail his physical and emotional discomforts. In one part of the Tristia Ovid writes:
"and the wines stand stiff, jugless but keeping the shape of their jugs, and the people don't drink draughts of wine--they eat pieces of it"


Our modern day temperature scales can be traced back to no earlier than the 17th century, therefore no temperature records from Ovid's time exist. However, chemists will immediately recognize that the phenomenon of freezing-point depression can be applied to estimate the temperature of Constanta, Romania, in the year 8 A.D., provided that the composition of the wine can be accurately estimated. Throughout the Roman Empire there were many kinds of wine consumed, some of which were diluted with water. However, the exact Latin words used by Ovid to describe the wine he writes about were "vina" and "meri". These words were used to describe undiluted wine.

Procedure
Do some research on the composition of the undiluted wines made and consumed today. (In other words, visit some stores and read the labels.) Several different kinds of wines exist, choose one "sweet" and one "dry" wine. From the information gathered determine the temperature that existed when Ovid wrote the Tristia by calculating the expected freezing point of wine using the freezing point depression constant of water (1.86 oC/1-m), the density of water, the density of alcohol, and the alcohol content of the wine.

Your instructor will provide you with two different kinds of wine: one "sweet" wine and one "dry" wine. Determine the actual freezing point of each of these wines. A bath cold enough to freeze the wines can be made by mixing together ice and salt or ice and methanol (ditto fluid).

Questions

  1. Report the information obtained on the wines you researched. Include in your report the alcohol content of the wines, the type of wine, and its sugar content, if available.
  2. Calculate the expected freezing point of each of the wines provided by your instructor for the laboratory investigation.
  3. From the difference in the calculated freezing point and the measured freezing point, determine the concentration of sugar in both molal units and percent composition by weight. (Note: you may have to make some assumptions to do these calculations. Clearly state all assumptions made!)


Teacher Notes

This is a nice lab to do. I do it with my advanced chemistry students on the last day of school before Christmas break. It gives students a chance to apply the chemistry they have learned to a commercial product. It also serves to unite science with literature and history.

When I first informed my principal that I wanted to bring in some wine for this experiment I got a look that said "ARE YOU NUTS!!" However, when I explained what I wanted to accomplish, he gave his permission and asked only that I inform him of the exact day that wine was being brought into the school so that he could respond immediately to any questions that might arise from parents or "concerned citizens". I have always honored that request and have never had a problem with my principal, parents, students, or "concerned citizens". In fact parents have always been very supportive whenever the topic of this laboratory exercise came up during parent-teacher conferences. In 1995 when I went to a local store to purchase the wine for this experiment, a voice said "is that for the Chemistry 2 Christmas Experiment". I turned to find a former Chemistry II student of mine working during his college's Christmas break. He remembered this experiment and it obviously left an impression on him. The greatest gift a teacher can receive is for a former student to say "I appreciate what you did, thank-you".


 
Questions? Comments??
Revised on: 03/14/2007 at 05:24:07