WEEK TWO

 

Liberato Cardellini

 

I am in debt to explain the content of the messages I received during the first week.  Some of the 30 messages was just their e-mail address; other sent me the completed questionnaire on the Motivated Strategies for Learning, two or three asked me if the general chemistry book that they have was OK for the course, a Chinese student asked for the meaning of an Italian word and the others send the solutions of the problems.  They are usual messages, but still precious because they are the promise of a dialog and this helps to break the barriers between them and us.

 

Monday: Two hours.

I asked them if they are seated according to the CL groups. After telling them the motto I would like to suggest for this course, “Fully engaged with enthusiasm”, I collected the problems solved as homework, the filled questionnaire and the concept maps (11). Friday night of the bygone week I sent the class a message, remembering them the homework: to study the mol, solving some related problems and to study again symbols and valences, and the acids’ formulae.

I explained the Bohr’s atom and we spent more that 1 hour going through again the balancing of chemical equations.  I used Problem 1 for explain the analysis of the problem and how to use the info collected for came at the problem’s solution.

 

As my personal homework, I corrected the collected problems (303) and I found that many of them were incorrect and often I found quite different results.  For example in the problem:

What is the mass of sodium carbonate that contains the mass of oxygen equal to 2.44x1022 molecules?

 

The results in their solutions cover quite a large gamut: 324,47 g; 2.58x101024 g; 0.5 g; 3.68 g; 2.86 g; 2.243 g; 8.50 g; 1.44 g; 1.4 g; 6.31x1022 g; 1.34x1022 g; 2.858 g.

 

From these results emerges the need to estimate the order-of-magnitude of the result and to present in the next lesson the significant figures.

 

I was a bit depressed about the results, so I sent the class a message entitled: disaster. In the message I asked them to solve again four problems, with the greater number of errors, in this way:

− to use the measurement units;

− to use the factor-unit method;

− to justify or argue about every step;

− to make the verification of the result;

− write the time needed for the task.

In the same message I congratulate with some students that worked seriously: one student solved a problem in 3 different manner and another one solved 23 problems.

I invited everyone to enter the fray, because all of them have the right and the chance to enjoy themselves.

 

Thursday: Three hours.

I started the lesson asking them if they are seated according to the CL groups.  Then I collected the problems solved as homework, the filled questionnaire and the concept maps (46) and suggested the feeling in the class: the enthusiasm must be more than yesterday and less that tomorrow.

I read the results of the correction of the 303 problems, name by name looking for the students and looking at her/his eyes, telling the errors, the good things found in some solutions, commenting about the few that reported the time spent on the task, etc.

I explained the periodic table and periodic properties for about 40 min., and the significant figures. Then we solved few problems asked by students.

 

I corrected 220 problems and I found errors in 26 solutions. I sent a message (go on with enthusiasm) to the class remembering that there were still errors in the four problems previously solved by some students.

I reported the names of successful students; two of them give me 20 solved problems and I thanked a student that give me 30 different solution of a logical problem. In the message I mentioned the fact that 8 students gave me zero solved problems. I invited the whom that have difficulties with some problem to come in my office.

 

Friday: Three and half hours.

I started the lesson asking them if they are seated according to the CL groups.  Then I collected the problems solved as homework, the filled questionnaire and the concept maps (31).  I remember them that in about two weeks there will be the first written examination on stoichiometric calculations.

I read the results of the correction of the problems collected the day before, name by name looking for the students and looking at her/his eyes, telling the errors, the good things found in some solutions, commenting about the few that reported the time spent on the task, etc.

Then I explained the chemical bond for about 40 min., a naive trick to establish the stiochiometric relationship between the atoms in a chemical formula.

I presented the sandwich metaphor as an useful tool to make easy and familiar the stiochiometric calculations based on chemical reactions and the limiting reagent.  We solved (well, they solved in groups) some problems.  I asked them to work on the task according to the CL roles.

 

At the end, I suggested the material to study, the CMaps to draw and two ‘special’ stoichiometric problems to be solved according to the rules of the game: it is allowed to use only the reasoning; mathematical crutches such as linear equations or systems of equations are not allowed.

 

Problem 5. A mixture formed by NaCl, NaClO3 and KClO3 contains 33.40% of oxygen and 16.00% of Na.  Calculate the percentage of K in the mixture

 

Problem 6. A mixture of CH4O, C6H6 and C7H6O weighting 44.37 g gives the elemental analysis: C = 68.74%; H = 8.905%; O = 22.355%.  How many grams of C6H6 are contained in the mixture?

 

 

I corrected 179 problems collected the day before and there were 14 wrong solutions. I sent a message (come on!) to the class telling that many students are going quite well.  I attached the Index of Learning Styles questionnaire, developed by Richard M. Felder and Barbara A. Soloman of North Carolina State University (http://www4.ncsu.edu/unity/lockers/users/f/felder/public/ILSpage.html).

 

In the week I received 29 messages, with more or less the same contents: questionnaires, info, a student thanks me about my messages, the Chinese student asked about what to study and the problems to solve.

 

A window in my office.

Pile of solutions from the first week: 702 problems.

 

Paraphrasing the Johnny Cash lyric poetry Going By The Book, I can comment about my students:

But the best is still to come !

 

Sorry for my English: It is 1:50 am!