High school chemistry as preparation for college chemistry

Science Education Center, The University of lowa, lowa City, IA 52242. High school chemistry students who determine the pH of astream and compare thei...
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High School Chemistry as Preparation for College Chemistry Joseph S. Krajcik Department of Curriculum and Instruction, University of Maryland, College Park, MD 20742 Robert E. Yager Science Education Center, The University of lowa, lowa City, IA 52242 High school chemistry students who determine the p H of astream and compare their data with datacollected inprevious years receive a chemical education different from students who measure the pH of a solution of hydrochloric acid supplied hy their teachers. For the former group, chemistry is being applied; students experience the relevance of the subject matter. For the latter group, most of the students do not know for what or when hydrochloric acid is used except for performing a step-by-step exercise during chemistry lab. Similarly, high school students who make soap, nylon, and other synthetic products in the high school chemistry lahoratory receive a different education from those students who halance chemistry equations on paper using symbols that are not tied to any direct experience of the student. During the '60's, curriculum innovators-often supported with funds from NSF-accepted the then widely held view that science would he interesting and appropriate for all if it considered science as known to scientists. Much time was spent with identifying the central themes, unifying ideas, conceptual schemes that characterized the particular science. The CHEM Study and CBA courses were the leading examples where the central ideas of chemistry were used as course organizers. Ten to 15 years later, chemical educators like Marjorie Gardner ( I ) suggested that a focus upon chemistry in ways it is known to chemists may he inappropriate for many students. The Interdisciplinary Approach to Chemistry (IAC) program that emerged was an example of high school chemistry that focused upon applicationssomething considered completely inappropriate a t an earlier time. Even with the introduction of IAC and the applied focus, few teachers were ready for such moves (2). Most teachers have accepted the view that students must first know basic chemistry; then they can learn about applications and perhaps some can even learn to use the information themselves. Measuring the pH of natural waters, making nylon and other synthetic products, and measuring the air quality are not typical experiences for the high school student (3).Most high school students see chemistry as an exercise in memorization and in solving mathematical problems. For instance, all "good" chemistry students can draw the Lewis structure for ammonia, can name its geometric shape, and can state that it has an unshared pair of electrons. But few high school students know the importance this chemical has for agriculture. The typical high school course often presents a watered-down version of college chemistry. Most high school texthooks are similar to college texts chapter by chapter. We need to examine whether this situation can provide the type of experiences that would he most beneficial for all high achool students. What type of experiences should a student receive in high school chemistry? This nontrivial question needs to he closely examined. The examination of this issue is crucial since over 6,000 scientific and technological articles are written daily. This represents an increase in new knowledge of over 13%yearly ( 4 ) . Thus, what we memorize in a class may be

obsolete before we even forget it. This information explosion raises some very crucial questions that must he examined closely. Should high school students memorize a watereddown version of quantum mechanics when this model may be obsolete by the time they become adults? Or, should high school students work a t developing reasoning and learning skills that can help them throughout their lives? Chemistry experiences that require students to explain and to test provide experience with reasoning and thinking skills. Applied chemistry and real world experiences provide more omortunities for use and development of student skills. .. An argument frequently advanced by some high school chemistry teachers and chemical educators is that traditionn l high schoul chemistry, which presents a simplified version of (dlr.gerhemistry, is essential for successful completion of ~ college chemistr? ( 5 ) .Often thii argument is used r t justify the tupirs covered in high school chemistry. A ~ t u d yperformed at thr I'nirersity of loa,a in the early 19:O's sheds some very important insights into this question. This investigation examined the following general questions: (1) Do high ability high school students who have not experienced

high school chemistry (hut who have high motivation, ability, and snecial tutorine available)oerform as well in a colleee ehemistry course as highability high school students who have experienced high school chemistry? (2) Do the attitudes these groups of students hold toward science differ at the end of the college chemistry course? This study consisted of offering standard college-level general chemistry to high school juniors during an eightweek summer session prior to their senior vear. Outstanding high s