edited by GARY E. DUNKLEBERGER Carroll County Public Schools
Chemistry: Learning for Mastery Leona B. Bronstein East Lansing High School. East Lansing, MI Teachers of chemistry often are plagued with the problems of the varying interests, abilities, and backgrounds (especially math) of the students they teach! Often the teachers suffer the dilemma of what to do with,the students who still have difficulty solving equations or understanding the mole conceot while thev are busv teachine the other students energy changes or equilibrium or redox equations! It was this tvoe of oroblem that led to the develooment. about 10 yeais ago, an individualized chemistry p;ogra& based on masterv. The course that was developed is a rigorous, quantitative approach to inorganic chemistry. It is hased on t h e idea that chemistry involves vertical, n i t horizontal, learning-that is, most of what is to he learned depends on and uses concepts that were learned previously.-It also recognizes that the interest and time commitment of the student is an imnortant factor in the learnine orocess. T h e course uses the HEM STUDY inquiry a p p r o k h and textbooks. Students must have oassed Algebra I with a C or better erade. ., . or have passed a test showing a minimum proficiency in math skills, inorder toenroll in thecourse. Students nroceed at differine rates, according to their individual abiiities and interests, through a prescribed set of learning activities involving readings, sound pages, films, laboratory experiments, and problem sets. They take tests a t the end of each unit and repeat tests until they demonstrate a minimum level of mastery of the concepts taught in that unit. In addition to a textbook. each student has a nacket of materials for each unit. The materials were developed, revised and i m ~ r o v e dseveral times over the nast 10vears. T h e materials fo;each unit include the following sectibns:
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Concepts to be Developed: This section is a list of the concepts to he learned in the unit. Reading References: The major textbook used for the course is "Chemirtrv: Fwndntions".' Since studrnts are indi. Ex~erimancal . viduallv. naced. several editions of the CHEM STUDY text can he . used at one time. As worn-out hooks are renlaeed. newer editions are ~~~~~,~~~ --.. ~.-. used, and a new set of reading references is added. When needed, supplementary notes are added to the packet of materials. This section is cooordinated with the Suggested Schedule explained helow. Audiovisual References: These include films and sound pages. We own all of the CHEM STUDY films, and students see these at the appropriate times in the units. The other major audiovisual reference is the sound page (a product of the 3-MCompany), These are sheets or pages involving both a tape and aviaual, which usually teach a single concept. They can be thought of as replacing the traditional chalk talk of the teacher. They have a Cmin recording on the hack and an illustration on the front which correlates with the recording. Each unit has four to eight of these sound pages that deal with the most important concepts of the unit. Students are able, in fact they are encouraged, to Listen to and repeat segments of these "mini-lectures" as often as needed to understand the concept. All of the sound pages have been recorded and drawn by the teacher. The scripts and illustrationsfor the sound pages are also included in the student packets for easy reference. ~
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Other Resource Material: These resources are intended to aid students who need mare help than is available from the textbook and the sound pages. They are usually commercially purchased tape-filmstrip programs for individualizedlearning. We have about 80 such programs and allow the students to cheek them out, along with a small "Study-Mate" machine, for use at home. Suggested Schedule: This is a one-page reference indicating the sequence of learning activities in the unit. It is very important since most of the learning in chemistry builds on previously learned material. It tells the student the order in which the activities in the unit are to he nerformed.It eives the readine references to the text as well " as the approprintr svund pages tq, hr studied as an aid in solving specific prul~iems. It rrlls when, in thecowre of the unit, the lnhe are to br done and indicate- any readings or round pages that would he helpful when writing up the lahs. Experiments: Since this is a laboratory-oriented course, experiments are a very important part of it. All lab instructions are selfcontained. In addition to the normal introduction, procedure, and question section, each lab includes a section called "Pitfalls and Cautions". This section eives the maior orohlems encountered and the cautions ahout oroeehures or che&ie& that could be hazardous. It gives the approximate arnuunt of time that needs to he nllowrd in order tocomplete thr lab xr,rk.Students doabrwt :lOerperim~ntsi n the couweof the yenr. lndi\idual xet~~~frhemiralsandglasswarafor each lab are permanently stored in boxes and ready for student use. Hardware is kept at the lab tables. Approximately six sets are kept for each specific lab. The science department employs a part-time laboratmy assistant who assists in the preparation and maintenance of these lahs. Problems: The problem section is divided into four parts. "Questions to Think About" include the questions which do not require written answers hut which students should know. They are frequently definitionor discussion questions. "Problems to Do" are the problems, generally quantitative, which are the major teaching tool of the unit. Students work out all of these problems and, after they have been checked, make corrections before taking atest. "For More Practice" include additional problems for students who are still weak on solving certain types af problems. These are referenced to the "Problems to Do" so that students may pick the types of problems for which they need more practice. "Challenge Questions" are included in some units and involve more difficult concepts or procedures. Students who do these problems are eligible for an extra test question which can earn them bonus points. When it was found that students with weakmathskills needed stillmore practice inorder to master certain concepts, another set of practice problems was prepared and is available from the teacher. These are called "Remedial Exercises". We found that many students do all of these sets of oroblems before takine a test. . Can You ...:This is a set of uhjectiws directed to the student. Each objective takes the form of a question binning with "Can You . . .", hence the name. Each test question is rrferenced to t h ~ objective being tested. ~~
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Journal of Chemical Education
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One of the major concerns of any individualized program Copies of student packets for units 1 through 3 are available from the author for $8.00 to cover costs and postage. Sample tests from each unit will also be included. Parry, R. W.; Bassow, H.;Menill. P.; Tellefsen. R. L. "Chemistry: Experimental Foundations," 3rd ed.; Prentice-Hall: Englewood Cliffs,
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NJ. 1982.
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is to construct atesting program which can provide multiple, unique tests on each unit. This problem was solved by constructing categories of test questions that match either a single "Can You" or, in a few instances, two or three "Can You's". Each unit has seven t o ten categories and each category has twenty questions in it. A student test consists of one question from each category of questions for a given unit. Originally, these questions were put on cards, one question to a card, and they were hand shuffled to make up the individual tests. However, during the last six months the process has been computerized by the use of two separate &mputer programs. The first is a word-proressing program for entering each question into the test tile. The particular nnbrram was chosen bmauue it arently farilitated the handling of upper- and lower-case-letters, superscripts, subscripts, and other notation necessary for printing chemistry material from an Apple 11. The other program is one we wrote ourselves. I t sorts the questions, randomly choosing one question from category I, one from category 2, etc. It is conceivable that when a student repeats a test, helshe may receive a single question which is the same as one helshe had previously, but no student ever receives an identical test. he tests emphasize understanding, not rote memory. Therefore, all tests are open-book, open-note, and all the test auestions reouire written or calculated answers. For this reasdn, they must be hand-graded. Students may proceed to a new unit onlv after a minimum proficiency has been demonstrated on each unit test. Grades in this course are based on quantity and on quality of work. A "C" student must complete 12 units with minimum of 70% mastery. Topics studied would be the use of signifirant figures in scientific measurements, Avogadro's Hypothesis and the mole, stoichiometry, the gas laws, solutions. the atomic theorv. " . structure of the atom, radioactivity, the periodic table, chemical bonding, energy changes, and rates of chemical reactions. A "B" student must complete 14 units with 80% or better mastery. Additional topics would include the general concept of equilibrium and solubility equilihrium. "A" students complete two additional units which cover acid-base equilibrium and oxidation-reduction reactions with 90% or better mastery. What would a student do during a typical unit? The folthrough unit 4 on lowing is a sample of a student's the eas laws. Day 1would begin with a short reading referenc; on molar mass and m d a r volume followed by three problems to solve. On Day 2 a reference on manometers and ~ a l t o n ' Law s of Partial Pressures, and problems using these concepts are presented. The next two to four days would be --Inh dnva. The first lab involves the reaction of magnesium metalkith hydrochloric acid to determine the amount of dry hydrogen gas produced by one mole of magnesium. The other is the determination of the pressure-temperature relationships of a gas. A sound page helps with difficult parts of the lab write-up. Finally, on the last two to three days of the unit, the student would see the film "Gas Pressure and Molecular Collisions", read two more references, listen to two more sound pages on the gas laws, and finish the prohlem set. These problems would he turned in, graded, and returned to the student for corrections before the test. On the ~-~~last dav hefore the test. the student would correct mistakes on t
