Leman
Tarhan
*a and
Burcin
Acar Sesen
b
aScience Faculty, Chemistry Department, Dokuz Eylul University, 35160 Buca, Izmir, Turkey. E-mail: leman.tarhan@deu.edu.tr
bHasan Ali Yucel Education Faculty, Department of Science Education, Istanbul University, 34452 Eminonu, Istanbul, Turkey. E-mail: bsesen@istanbul.edu.tr
First published on 16th April 2012
This study focused on investigating the effectiveness of jigsaw cooperative learning instruction on first-year undergraduates' understanding of acid–base theories.Undergraduates' opinions about jigsaw cooperative learning instruction were also investigated. The participants of this study were 38 first-year undergraduates in chemistry education department in an education faculty in Izmir, Turkey. A prerequisite knowledge test was applied to both experimental (N = 18) and control groups (N = 20) before the treatment in order to identify undergraduates' prerequisite knowledge about ‘acids and bases’. Independent t-test was conducted to compare the prerequisite knowledge test scores for groups and no significant difference was found in terms of mean scores (t = 0.42, p > 0.05). The subject of “Acid–Base Theories” (Arrhenius, Brønsted–Lowry and Lewis Theories) was taught using jigsaw cooperative learning in the experimental group and with regular teacher-centered approach in the control group. After the instruction, the acid–base theories concept test was administrated to investigate undergraduates' conceptual understanding. Independent t-test results showed significant difference in terms of mean scores (t = 4.65, p < 0.05).The results also indicated that undergraduates in the experimental group had fewer misconceptions and understood the concepts more meaningfully than undergraduates in the control group. In addition, individual interviews reflected that undergraduates had positive opinion about jigsaw, and they believed jigsaw is an effective cooperative learning technique that promotes positive attitudes and interest, develop inter personal skills as well as their learning achievements.
Researchers have indicated benefits of cooperative learning as higher academic achievement, greater persistence through graduation, higher level reasoning and critical thinking skills, deeper understanding of learned material, better attention and less disruptive behavior in class, lower amounts of anxiety and stress, more motivation to learn and achieve, positive attitudes to subject matter, higher self esteem (Cooper and Mueck, 1990; Johnson et al., 1991; McKeachie, 1986). This shows that students achieve more, improve their social skills, and increase their capacity to work productively together while working in cooperative learning environment.
There are many cooperative learning techniques and most widely used of them are Student Teams-Achievement Division (STAD; Slavin, 1980), Teams-Games-Tournament (TGT; Slavin, 1980), Learning Together (Johnson and Johnson, 1994); and Group Investigation (Sharan and Hertz-Lazarowitz, 1980), Jigsaw (Aronson et al., 1978.; Slavin, 1980). The cooperative learning technique selected for this study is jigsaw, which enhances cooperative learning by making each student responsible for teaching some of the learning issues to the group. In this structure, students are members of two different groups, the ‘home group’ and the ‘jigsaw group’ (Fig. 1). Initially, students meet in their home groups and each member of the group is assigned a portion of the learning issues to learn as an ‘expert’ (Slavin, 1980). The home groups then break apart, like pieces of a jigsaw puzzle, and students move into jigsaw groups, which consist of members from the other home groups who have been assigned the same portion of the learning issues. While in the jigsaw groups, the students discuss their particular material to ensure that they understand it. Students then return to their home groups, where they teach their material to the rest of their group (Colosi and Zales, 1998).
Fig. 1 The jigsaw cooperative learning process. |
Researchers underlined that jigsaw is an effective cooperative learning technique that promotes positive attitudes and interests in the learning issues, development of communication skills between students and also higher learning achievement in science (Lazarowitz et al., 1985; Colosi and Zales, 1998; Doymus, 2008a; Eilks, 2005; Young et al., 1997). In the field of chemistry education, relatively little research has been done on the use of jigsaw techniques. In the one of the study, Eilks (2005) discussed using a modified jigsaw-classroom method to teach atomic structure in the 9th and 10th grades, and found that the jigsaw techniques have potential to improve students' attitude towards science. Doymus (2008a) investigated the effect of jigsaw cooperative learning versus individual learning methods on students' understanding of chemical equilibrium in a first-year general chemistry course and found that students in the jigsaw class were more successful than those in the individual learning class. In another study, Doymus (2008b) examined the effectiveness of jigsaw technique to teach ionic bonding, covalent bonding, hydrogen bonding and van der Waals forces, and found the same results as his previous study.
The subject of acids and bases are also an important and fundamental concept in chemistry learning as early as primary school, right through the university level. Researchers have shown that students have many misconceptions related to acid and base theories (Banerjee, 1991; Bradley and Mosimege, 1998; Cross et al., 1986; Rayner-Canham, 1994; Schmidt, 1995).Bradley and Mosimege (1998) asserted that university students have problems with Arrhenius theory. They found that 38% of them were able to identify the important objection against the theory. Cross et al., (1986) also indicated that 47% of the first-year university students gave the Brønsted–Lowry definition and only 14% gave the Arrhenius definitions of acids. Vidyapati and Seetharamappa (1995) investigated higher secondary school students' concepts of acids and bases. In this study, it was found that the percentage of students citing the right examples of acids and bases according to the Arrhenius, Brønsted–Lowry and Lewis theories is more than the percentage of students who gave the scientific definitions, and they suggested cooperative learning in place of normal lecture classes to overcome this ineffectively construction of knowledge. Hawkes (1992) observed that the Arrhenius acid–base theory confused students, and when asked to use the Brønsted theory, which applies to a variety of bases, students' thinking was still dominated by the Arrhenius theory, in which only OH− ion-producing substances are considered as bases. For this reason Hawkes (1992) suggested that the Brønsted theory should be introduced first, and that the Arrhenius theory should only be used as a historical footnote. In the other hand, Demerouti et al., (2004) reported that students from upper secondary school were more familiar with the Arrhenius theory, and they did not use the Brønsted theory to explain the properties of acids and bases.
As a conclusion, the results of those studies underlined that students have some difficulties and misconceptions about acid and base theories.
What is the first-year undergraduates' prerequisite knowledge about acid and base theories at the beginning of the instruction?
Does jigsaw cooperative learning contribute to better conceptual understanding of acid and base theories in first-year undergraduates' than teacher-centered approach?
What are the opinions of experimental group undergraduates about the treatment based on jigsaw cooperative learning?
Acids and bases are related to many other chemistry concepts such as atom, molecule, solubility, solution, the periodic table, electronegativity, chemical bonding, chemical reactions, thermodynamics, and chemical equilibrium. Researchers have underlined that the causes of student difficulties in acid–base chemistry have been ascribed to the existence of many misconceptions related to these aforementioned concepts (Demircioğlu, 2003; Nakhleh and Krajcik, 1993; Nakhleh, 1994; Smith and Metz, 1996; Schmidt, 1997; Sheppard, 1997). For this reason, in this study, the prerequisite knowledge test consisting of 16 multiple-choice items was developed by the researchers to identify undergraduates' understanding the concepts that effects learning of acids and bases. The items of the test were constructed by considering students' misconceptions determined in the literature (Ebenezer and Gaskell, 1995; Griffiths and Preston, 1992; Peterson et al., 1989; Sanger, 2000). Each item had one correct answer and four incorrect answers (distracters). The distracters are derived from actual student misconceptions gathered from the literature. For the content validity and error reduction, the items were evaluated by seven chemistry educators. The prerequisite knowledge test was piloted with the sample of 152 undergraduates for the reliability. After the item analysis the reliability coefficient (KR-20) of the test was found to be 0.77.
Each answer was evaluated by researchers and two expert chemistry instructors. The scores were compared and discussed until an agreement was reached.
What is your opinion about the effects of jigsaw cooperative learning application on you and your friends' chemistry achievements?
If you compare the jigsaw cooperative learning technique to the teacher centered approach, how can you explain the differences about the learning process and the roles of instructor's and students?
In an cooperative learning environment, group formation is very important for success. In this study, stratified random sampling was used as a method of group formation. This method of group formation involves creating small subgroups (strata) of undergraduates stratified along a specific dimension and then randomly choosing group members from each of these strata. By design, stratified random sampling yields groups that are balanced across the dimension used to form the strata (Fraenkel and Wallen, 2005). In this study, the undergraduates in the experimental group, were stratified random to six home groups considering their chemistry achievements. As presented in Fig. 2, there were three undergraduates in each home group. Each member of the groups was assigned a portion of acid–base theories and then they moved into three jigsaw groups including six members to be expert. Jigsaw group-1 studied Arrhenius Acid–Base Theory, jigsaw group-2 investigated Brønsted–Lowry Acid–Base Theory, and jigsaw group-3 searched Lewis Acid–Base Theory. During this process, they were encouraged to develop their hypothesis and to make task distributions in the fifteen minute period under the guidance of the instructor. Then, they were directed to study their own subtopics outside the class. Undergraduates benefited from library, textbooks and internet, and they worked under the supervision of the instructor to achieve the learning objectives.Undergraduates then returned their home groups and taught their own expertise subtopics to the rest of their group.
Fig. 2 Studies in home and jigsaw groups. |
• Arrhenius investigation on galvanic conductivity of electrolytes,
• salts dissociate when they dissolve in water to give charged particles which Arrhenius called ions,
• why acids have similar characteristics, since they all give H+ ions when they dissolve in water,
• why bases have similar characteristics, since they all give OH− ions when they dissolve in water,
• ionization equation of Arrhenius acid and bases in the water,
• identification of Arrhenius acid and bases,
• the limits of Arrhenius theory.
• Brønsted and Lowry separately proposed a new set of definitions for acids and bases,
• acids are any substance that can donate H+ ion to a base,
• bases are any substance that can accept H+ ion from an acid,
• the role of water in acid–base reactions,
• the reason of formation hydronium ion in the water,
• dissociation of Brønsted and Lowry acid and bases in the water,
• part of the acid remaining when an acid donates a H+ ion is called the conjugate base and the acid formed when a base accepts a H+ ion is called the conjugate acid,
• acids and bases can be ions or neutral molecules according to Brønsted and Lowry theory,
• acid and bases can be applied to solutions with solvents other than water and even in reactions that occur in the gas or solid phases,
• the limitations of Brønsted–Lowry theory.
• Lewis acids are any substance that can accept a pair of nonbonding electrons,
• Lewis bases are any substance that can donate a pair of nonbonding electrons,
• Lewis acids are those which can form a new covalent bond by accepting a pair of electrons and Lewis Bases are those that can form a new covalent bond by donating a pair of electrons,
• formation of complex ions according to Lewis theory,
• identification organic molecules that act as a Lewis acid or Lewis base,
• the limits of Lewis theory.
After the presentations of each jigsaw group, a 15 min break was taken. In the third lesson, undergraduates were moved to their home groups to complete their task related to the ‘Acid–Bases Theories’.
• Arrhenius theory can only classify substances when they are dissolved in water since the definitions are based upon the dissociation of compounds in water,
• Arrhenius theory does not explain why some compounds containing hydrogen such as HCl dissolve in water to give acidic solutions and why others such as CH4 do not,
• Arrhenius theory can only classify substances as bases if they contain the OH− ion and cannot explain why some compounds that don't contain the OH− such as Na2CO3 have base-like characteristics,
• Brønsted theory explains acids and bases can be ions or neutral molecules,
• Brønsted theory explains bases can be any molecule with at least one pair of nonbonding electrons,
• Brønsted theory explains the role of water in acid–base reactions; H2O accepts H+ ions from acids to form H3O+ ions,
• Brønsted theory can be applied to solutions with solvents other than water and even in reactions that occur in the gas or solid phases,
• Brønsted theory relates acids and bases to each other with conjugate acid–base pairs and can explain their relative strengths,
• Brønsted theory explains the relative strengths of pairs of acids or pairs of bases,
• Only Lewis theory explains formation of complex ions,
• Only Lewis theory explains organic molecules acid or base characterizes.
Undergraduates' responses to the prerequisite knowledge test indicated that they had misconceptions related to identification chemical bonds and inter molecular forces, confusion ionic and covalent bonds, confusion London and dipol-dipol forces, solubility, and chemical equilibrium (Table 2). Because these concepts were important for learning ‘Acid and Base Theories’, undergraduates in both group were taught these concept before and during the instruction.
Group | N | Mean | SD | t | p |
---|---|---|---|---|---|
Experimental | 18 | 21 | 7.4 | 0.4 | 0.68 |
Control | 20 | 22 | 5.4 |
Undergraduates' misconceptions | Exp. Grp (%) | Cont. Grp (%) |
---|---|---|
HCl is an ionic compound. | 67 | 70 |
H2 includes hydrogen bonds. | 44 | 30 |
London forces are stronger than dipole–dipole forces. | 56 | 40 |
Because HF molecule can ionize in the water, it has high solubility. | 67 | 75 |
If equilibrium constant bigger than 1, the reaction occurs more rapidly. | 33 | 40 |
All the acids and bases are strong electrolyte. | 50 | 60 |
Hydrogen is a metal in I-A group of the periodic table. | 55 | 55 |
Only solutions of ionic compounds conduct electricity. | 39 | 40 |
Instruction of Arrhenius, Brønsted–Lowry, and Lewis Acid–Base Theories was conducted with jigsaw cooperative learning in the experimental group and with teacher-centered approach in the control group. Immediately after the instructions the acid–base theories concept test was administrated to determine undergraduates' understanding. The independent sample t-test results showed that the undergraduates who trained with jigsaw cooperative learning significantly had higher scores than those taught by teacher-centred approach in terms of acid–base theories concept test mean scores (t = 4.6, p < 0.05, Table 3).
Group | N | Mean | SD | t | p |
---|---|---|---|---|---|
Experimental | 18 | 24 | 4.1 | 4.6 | 0.002 |
Control | 20 | 16 | 6.7 |
Undergraduates' responses to each item in the acid–base theories concept test reflected that undergraduates in the experimental group had significantly fewer misconception and understood ‘Acids and Bases Theories’ more meaningfully than undergraduates in the control group (Table 4). While two of the misconceptions in Table 4 were first identified in this study, six of them had been previously documented in the literature.
Undergraduates' misconceptions | Exp. Grp(%) | Cont. Grp(%) |
---|---|---|
a Firstly identified misconceptions in this study. | ||
Because HS− has hydrogen, it is Lewis acid. | 0 | 45 |
Because HS− give its proton, it is Brønsted–Lowry acids. | 6 | 40 |
CN− ion takes proton from the base and thereby it is Arrhenius base. | 0 | 35 |
There is no electron transfer between NH3 and BF3 molecules. | 6 | 40 |
Acids are the substances that only give H+ ions and bases are the substances that only gave OH− ions. | 11 | 45 |
Bases are the substances that give proton and acids are the substances that gain proton. | 11 | 50 |
Arrhenius theory explains transferring of H+ and Brønsted–Lowry theory explains transferring proton.a | 6 | 55 |
According to Lewis Theory, ions should be combined to make new products.a | 0 | 45 |
Results reflected that undergraduates in the control group commonly had difficulties about Lewis Theory, and they confused Arrhenius and Brønsted–Lowry Theories. For example, one of the item, it is asked to undergraduates to identify the acids and bases in the reaction of HS− + CH3Cl → CH3SH + Cl− according to ‘Acid–Base Theories’. It was required undergraduates to answer this item as HS− is Lewis base, because it is an electron pair donor. While undergraduates in the experimental group correctly answered this item, 85% of the undergraduates in the control group gave the wrong answer. 45% of them identified HS− as Lewis acid because of having hydrogen. 40% of them thought that HS− is Brønsted–Lowry acids, because of giving proton.
In the other item, undergraduates were required to explain some sample reactions according to Lewis Theory. 45% of the undergraduates in the control group classified the reaction between NH3 and BF3 molecules as Lewis Theory, because they believed that new complex products as BF3NH3 should be formed according to Lewis theory. Those undergraduates also could not explain the reaction between CN− and H2O molecules deped on Lewis Theory. In the other hand, 40% of undergraduates in the control group could not explain this reaction according to Lewis theory and they indicated that there is no electron transfer between NH3 and BF3 molecules.
Those misconceptions underlined that over 35% of the undergraduates in the control group did not understand electron transfer between acids and bases depend on Lewis theory, could not explain the basic characteristics of some samples do not include OH− ions, confused H+ ion and proton. This situation indicate that undergraduates commonly prefer to define acid and base according to Brønsted–Lowry Theory, and had difficulties in explaining Lewis acid–base theories and confused acid and base theories with each other as mentioned by the other researches (Bradley and Mosimege, 1998; Demerouti et al., 2004; Zoller, 1990). This can be caused because the regular chemistry curriculum generally highlights Arrhenius and Brønsted–Lowry Theory, and the differences between these theories do not give apprehensible as indicated in the previous studies by Carr (1984), Schmidt (1995), Vidyapati and Seetharamappa (1995).
In the light of the results of this study, it can be said that jigsaw cooperative learning instruction is successful in improving students' conceptual understandings and preventing misconceptions. The findings are consistent with earlier studies as those of Doymus (2008a, 2008b), Eilks (2005) which revealed that the jigsaw method leads to higher achievement.
In order to identify undergraduates' opinions about jigsaw cooperative learning application, 15-minute period semi-structured individual interviews were conducted with all the undergraduates in the experimental group after the instruction. As shown in Table 5, undergraduates indicated that this instruction positively effected their attitudes towards chemistry, learning achievements, responsibilities, and social skills. 67% of the undergraduates indicated that jigsaw cooperative learning increased their chemistry achievements, and 61% of them began to think that chemistry is not memorization. In the other hand only 44% of them required using jigsaw cooperative learning in all the lessons. This result underlined that although undergraduates recognize the power of jigsaw cooperative learning, more than half of them do not want to be taught via jigsaw. They also do not want to study in group. This results underlined that undergratuates are not accustomed to this type pf learning. Threfore, application of jigsaw or the other cooperative learning techniques should be used most widely in chemistry and science classes. Additionally, undergarduates generally have positive attitudes and interest towards jigsaw techniqe. These findings are in agreement with previous research findings which revealed that the jigsaw method increased students' attitudes and interest (Dori 1995; Doymus et al., 2004).
Experimental Group Undergraduates' Opinions about Jigsaw | (%) |
---|---|
Using jigsaw cooperative learning in all the chemistry lessons may increase my chemistry achievement. | 67 |
Because we shared our ideas and knowledge, I learned better. | 50 |
I learned chemistry is not memorization. | 61 |
I wish jigsaw cooperative learning is used in all the lessons. | 44 |
I learned the research techniques in the library and internet. | 72 |
I began to like chemistry after jigsaw cooperative learning instruction. | 56 |
Working with friends increased my interest to chemistry. | 44 |
Instructor's monitoring helped us to plan our research. | 78 |
I would rather educated by instructor than studying in the group. | 22 |
The feedback given by the instructor helped us to reduce errors in our study. | 83 |
I feel my confidence level in investigating has improved after the group study. | 61 |
I enjoyed while working in my group. | 78 |
I liked to study with my friends in the groups. | 44 |
Working in groups developed the relations between friends. | 50 |
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