Case: Mendeleev - User's Notes

Author - Tom Huber – Summer 1998 ----- Comments are listed newest to oldest

Name: Dale Moore
Phone: 752-2754
Email: moore_de@mercer.edu
CaseUsed: Mendeleev Periodic Table
MeetTime: TR (75 minute classes)
WeekUsed: 5th week
Date: 5/27/98
Comments

I provided students with blank cards and a tabulated set of information about the elements up to calcium, and asked students to organize them much like Tom's case.
Information that I included: Element name; phase; binary (only) combinations with hydrogen and oxygen; and relative mass.
I then added titanium and asked for predictions about eka-aluminum. Finally, we discussed the tellurium- iodine dilemma (reversed masses).

This case worked particularly well in both stimulating the students, and in providing them with a memorable activity.

As with my other cases, I asked the students to learn about Dmitri Mendeleev by searching the Internet.

suggestions none

references none

MeetTime: MWF (50 minute classes)
WeekUsed: 5th week
Date: 10/28/98
Comments

I used the Periodic Table building activtity in conjunction with my series of biographic activities. Students are given the subject and instructed to come to class with some background information. We do a brief review of the scientist and the relevant scientific concepts.

In their discussion groups, the students attempt to construct the Periodic Table. I give each group a sheet of information about the elements that Mendeleev knew. I also give them twenty blank 2.5" x 3" cards (3" x 5" cut in half). It has previously turned out that groups that first organize the elements by phase (gas, metallic solid, nonmetallic solid) then attempt additional organization generally complete the Periodic Table before groups that think they can construct the Table from memory.

Once we've constructed the Table, I ask them to predict the properties of eka-aluminum (scandium) and other "undiscovered" elements. Then we cast the "theory of periodicity" illustrated by the Table in written form.

I've been very pleased with student enthusiasm and performance in this activity and plan to continue it. (Used in three sections to date.)

Name: John Shepherd
Phone: 752-2713
Email: shepherd_jd@mercer.edu
MeetTime: MWF (50 minute classes)
WeekUsed: 3rd week
Date: 5/26/98

Comments

I used only the organic molecules set as we discussed pattern recognition in Ziman (RK).

I replaced the acetaldehyde card with a blank and gave a set to each group. They were asked to organize the cards in such a way as to reveal patterns among the compounds and their properties. They were told that they would have to fill in as best they could the information that should go on the blank card.

One group focused quickly on the structural formulas, while the others looked for unambiguous patterns among the numerical data. By then end of 50 minutes, all of the groups had found the 4 x 4 array, with CO2 as an oddball. Once they had the pattern, they found it easy to fill in the blank card, although there were ambiguities for name and ranges for numerical properties.

At the next class, we talked about patterns as convenient summaries of information, about how they had gone about looking for patterns (lots of trial and error, but looking for ways to make all of the numerical trends consistent). We made the by-then-obvious connection between patterns theories and predictions.

I then asked them to develop a "theory of delta H" or at least a hypothesis about what determined this property of the molecules. Although this was really beyond their chemical background (and mine), they could all look at the molecules to make a coherent statement about number of carbons and functional groups and delta H. We talked about how they could test their theories with new compounds etc. Pattern implies some underlying process.

Suggestions none

References none