Michael J. Pavelich Dept. of Chemistry 8 Geochemistry Colorado School of Mines Golden 80401 and Michael R. Abraham Unwersity of Oklahoma Norman, 73019
I
An Inquiry Format Laboratory Program for General Chemistry
During the last four years, we have been experimenting with different lahoratory formats for use with the general chemistry course for science majors a t the University of Oklahoma. Our chief reason for developing these materials has been our feeling that the educational value,of traditional lahoratory iustifv formats is too limited to . . the monev and student time Invested in them.'l'his paper reports our w ~ u,ith k a lnhorntow format called rulded wm-ended inauirv. . . Our e\,aluation of this format indicates that it is i u p m u r tc, traditional (verification) Iahorntorirs in sweral important respects. Goals I t was decided that the lahoratory program should attempt to accomnlish the followine eoals: (1) acouaint the student with funhamental labor&& techniques and procedures. This goal is a traditional one which any lahoratory which serves science majors needs to meet. (2) giue the student experience with aspects of scientific inquiry. By this we mean having the student experience such activities as: identifying a prohlem ro studv, drsigning experiments, and analping and explaining data. Finally, the l a h ~ m t o r yshould he designed l o 0 1 vnhanrc t h r rrudpnr's thinking abilirv louord mwc, abstract thinking processes. This g o d can hk best clarified by using the intellectual developmental theory of Jean Piaget. Piaget's theory and its application to educational settings is discussed in several references (1-6). Table 1. Characteristics of Lab Typesa
Order Choice of Problem Experiment Design Data Analysis Data Explanation a
Verifi-
Guided-
Open-
cation
I~OU~N
lnouiw
C-D T T T T
D-C
D-C
T
S S
C: Concepts D: Data T: Teacher
S: Student
100 1 Journal of Chemical Education
T S
S
S S
Laboratory . Types .. The characteristics of three lahoratory types which we will call verification, guided-inauirv, and oven-inanirv are summarized in able-l (7). w h a t & are calling the v&ification type is the laboratory format e m ~ l o v e din oracticallv all c&nercially avai~ahl~general che&ist;y lahor&ry ma&als. The first thing the students encounter when they see the verification lab manual is a detailed explanation of the chemistry they are going to encounter in the lahoratory. The students are expected to read this introduction before coming to lab and to have understood it to some degree before heeinnine the lab work. Therefore in the verification format. the students are expected to understand the concepts before they experience the data. The next thine the students see is a det a h d description of. the chemical prwedurei thry are w p posed ro r o thrtnxh. Most otten the m a n ~ aalso l includes nn explanatl%n of how the data obtained are to be analyzed to generate some specific number (e.g., a molecular weight). Thus in the verification lahoratory the intellectual decision making exercises that characterize lahoratory work are performed for the student. The teacher (or lah manual) chooses the problem, the experimental design, the method of data analysis, and (through the introductory theoretical discussion) suggests an explanation for the data. In contrast students with the euided-inauirv format are not given a theoretical introductio'or methods of data analysis; thev are given onlv explicit ex~erimentalinstructions. Thus the; are told what problem td investigate and what experiment to do. hut thev are reauired to eenerate their own analysis and explanation of th;data. detailed explanation of the guided-inauirv format with e x a m ~ l e scan he found in
' h s pnprr ir a rndifimtwn of rhr pawn presented hv the a u t h m a t r h r S\.napusiurnun F'I:ICPI and the'I'~u~ h:ng ~,IChrrn~str?g~ven nt thr Amrrican C'hemiral Surlrty Con\tntim. Ncu Orlrans, hlarrh 197:.
What we label as an open-inquiry format has characteristics opposite to the verification format. These characteristics are shown in the last column of Tahle 1.The students first collect data and then draw concepts from these data. They are allowed to choose the problem they want to investigate, are required to design their own experiments and to formulate an analysis of and an explanation for their data. In other words, what we call open-inquiry is very much a mini-research experience for the student. In comparing the characteristics of these three lahoratory types we have come to the conclusion that the open-inquiry format is most compatible with our goals. As regards the first goal (listed ahove);any welLplann;d ~ a b o r a t &experience ~ should thoroughly acquaint the student with fundamental techniques and procedures. Considering the aspects of the scientific-inquiry goal, it is our feeling that students need to do more than simply hear about these aspects. They must a t some point personally experience the associated decisionmaking if they are to develop a reasonable understanding of how science operates. Piagetian-type test (9) results on students entering our general chemistry course show that only 14% have fully entered the stage of formal operations, 8% are a t the concrete stage, while 78% are in the transitional stage. This is consistent with other research results (5)which show that avast majority of college age students have not yet entered the stage of development which allows them to think abstractly. It has been found that concrete, transitional, and furmal 9tudents learn better i l a concrete instructional stratt:gy is utilized 14). Furtht!rmore, it has hwn suggestrd that such a strntrgy is most a p p r q m a t e lor enhancing al13rract thinking ( J , 6 ) .Cuncrere instrtlctimal stratvm -" is an acti\.itv-centered stmtwv which is "minds-on" as well as "hands-&." More specifically this amears .. to reauire that students he allowed to develop concepts from their own experience (i.e., D C in Tahle 1)and that they have the freedom to deal with concepts a t their own intelleciual level. Only open-inquiry would dlow the latter.
-
An Inquiry Laboratory Program Althoueh we wish our students to have an open-inquiry . . experitmu., we cannot expect freshman students to he ahlr to walk directlv intoa lab.chumsr a problem to investigate,design experiments, analyze their data, and explain it. e hey simply do not have the background in either techniques or concepts of chemistry to do this. Therefore, in order to get the students into an open-inquiry situation, we must provide them first with an experience which does two things; gives them some background in the techniques available and in the concepts of chemistry. We use a guided-inquiry format for this introductow experience. Thus the laboratories in our program have two a guided-inquiry experience (taking one lab session timed to precede the lecture discussion of the topic) followed by an open-inquiry experience (taking one to two lab sessions timed to coincide with lecture discussion of the tonic). . In order to clarify how this guided/open-inquiry format works, the lahoratory dealing with heats of reactions will he discussed. The guided-inquiry phase begins with a qualitative experiment where the students are instructed to dissolve various ionic solids in a beaker of water in which is suspended a thermometer. They are instructed to record their ohservations. They will observe that with some dissolution reactions the water temperature increases while with others it decreases. They are then asked to draw conclusions from these data. Through this experience and from discussions with other students andlor the lab instructor, the students form the idea that chemical reactions are connected somehow with heat.
.
With this idea established, the lab progresses to a quantitative investigation of the phenomenon. The students are given experimental instructions for collecting time versus temperature data on the dissolution of anhydrous magnesium sulfate and are asked to determine the temperature change for this reaction from a plot of their data. The students are then given the heat capacity equation and are asked to calculate the quantity of heat released in the reaction. They are then instructed to perform the same experiment on a different size sample of magnesium sulfate and to collect three other sets of data from fellow students. All these data are then summarized in tabular form. Finally, the students are asked to draw some conclusions from these data. They are asked to find patterns and eventually to express these patterns in terms of an algebraic equation. Through this experience and discussions the students derive Hess's first law; that the amount of heat is directly proportional to the amount of material reacted. Of course the quality of the conclusions does vary from student to student. The more concrete students operate on a aualitative level (''the temperature increases as the amouni of MgSOI used is increased.") while the more formal students use detailed mathematical explanations (giving the result as Q = K (weight) supported by graphs or other mathematical manipulations of the data).' With the completion of the guided-inquiry experience, the students have a background in techniques and some hackground in concepts. w i t h this background they are able to do some open inquiry. As shown in Tahle 1,the characteristics of open-inquiri a& to allow the students to control all aspects of the investigation from choosing the problem through explaining the data. Consistent with this, the lab manual for open-inquiry is simply a series of short, experimentally ambiguous, statements (called systems) suggesting possible areas the student may want to investigate (see Tahle 2). That we are not concerned that the students do a particular experiment is shown in System 6 where the students are reminded that they can do any investigation of their choosing, as long as it relates to the topic of heats. The ground rules for open inquiry Table 2. Open Inquiry Systems From the Heat Laws Laboratorya System 1 investigatethe heat lost or gained when a specific chemical or group of chemicals are added to water System 2 Investigate the heat lost or gained when the following interactions occur. Investigate any one of the three or investigate possible relationships between the three.
a. Dissolve solid sodium hydroxide in water.
b.
Dissoive solid sodium hydroxide in a dilute hydrochloric acid solution.
C.
Mix a sodium tion.
NaOH(s)+ Hf(aq)+ CI-(aq)
-
H20
+ Nat(aq) + Cl-(aq)
hydroxide solution with a dilute hydrochloric acid solu-
System 3 Investigate lhe heat iost or gained when a "hot"or "mid piece of metal is added to water. System 4 InveStigate the heat iost or gained when water at a high temperature is added 10 water at a lower temperature. Svstem 5 investigatethe heat lost or gained in a calorimeter when liquids other than water are used for systems 3 or 4. nvestogatc the hear o5tor ga ned w Inany otner system or any mod l c a l ~ o nof any of me above syslomr For salcty reasons, discuss your system with the
and teaching techniques are invited to contact the authors. Alternatively, a more detailed description of a stoichiometric Guided Inquiry experiment can be found in ref. (8)
lab inrtrudor before proceeding.
me table ir abbreviated.System also comain suggested Memicals to ureand safely In~lYCIIW*I.
Volume 56, Number 2, February 1979 ' 1 101
are as follows. T h e students are to spend some time talking with each other and coming to some conclusion as to what system they want to investigate. If they have no ideas, they are just to choose a system a t random and experiment with the chemistry until they find a problem that interests them. They are then to outline hriefly the investigations they plan to conduct and to discuss these experiments with the-lab instructor. The lab instructor a t this initial point checks these experiments only for equipment availahiiity and for safety. At this point the instructor is not to comment on the worth of the experiment designed. If there is a problem with the student-designed experiments it will become known to the students as they conduct the experiments. There is sufficient time built into the laboratory schedule to backtrack and correct errors. Other rules governing open inquiry are that the students are to spend a t least 2/, of actual session time conducting their investigation. If thev satisfv themselves in one mvest~&iticmin a sh&er twne, t h y are (0 hegin a w t h e r illvesticatim. At the end d t h e ol)en-inq~~irv enrh student is to submit a separate detailed laborator; report on the experiments giving the purpose of the experiment, the experimental design, the data, and the analysis and explanation of the data. As an example of the quality of work done by students in the open-inquiry mode, the reports of one student pair who chose Svstem 3 are detailed below. The intention of Svstem 3 was to have the students collect experimental data which would give them some insight into the heat capacity equation; Q = CMAT. This pair of students reported the following kinds of experiments. Thev took various brass and aluminum slues and heated them fora certain amount of time (actual time n i t specified) in a Bunsen hurner flame. These slugs were then dropped into 250 ml of water, the water was stirred, and the temperature change of the water was noted. The data they collected were analyzed by making plots of the temperature change of the water versus the weight of the brass or aluminum slug. Two plots were generated in this manner, one for brass and one for aluminum; hoth plots were linear. Although the taking of data and its analysis were quantitative, the conclusions (explanations) were stated only qualitatively. The first conclusion was "the more substance. the more beat it can absorb." Thus, they had come to a realization of the "Q-M" relationship in the heat capacity equation. The second conclusion was "different metals absorb different amounts of heat," showing some realization of the "Q-C" relationshio. Furthermore,the students felt that there had to he some controlling factor in the amount of heat different types of metals would absorb. Although they had only two examples, aluminum and brass, they used them to offer the explanation that "the lower the density of the substance, the more heat it will absorb." Thus, we have an example of fairly average students conducting a well-controlled experiment and generating a fair amount of knowledge about the heat capacity equation. All of the laboratories used in the two semesters of general chemistrv are constructed in the euidedloven-inauirv twophased firmat. T o date we have developed 1ahorato;ies;n the following topics; ohvsical measurement, stoichiometric rela. . timships, gas laws, heat laws, periodicity, generalized equilihria, wid-~IHSI! t!quilil)ria, nci(l-hawanalviis. (:l~!rtn~chrmicd cells, and qualitative cation analysis. As each laboratory is independent of the others, their sequenching is flexible. We allow the order of content oresentation in the lecture todictate laboratory sequencing. Grading of the laboratory reports from inquiry experiments requires non-traditional criteria. It is explained to the students that in science data can be interoreted manv wan. and as lone as that interpretation follows logically from thki; data, it is resonable one and will be accepted by us. Most of our students do their experiments very carefully simply because they learn that carefully collected data are easier to interpret. The success of implementing an inquiry laboratory in a large university depends upon the ability to train laboratory assistants to
a
102 / Journal of Chemical Education
exhibit the teaching techniques, especially the questioning techniques. that allow students to draw their own conclusions. We ha;e had the most success in givingonr graduate teaching assistants a two-day workshop whose main emphasis is a "hands-on" experience with the same guidedlopen-inquiry experiments they will later teach. Evaluation We have been extremely pleased with the response of our freshmen students to this open-inquiry laboratory. The vast majority of them get into it with ease and enthusiasm. Often we have been asked by students to provide additional lab time to do further experiments in order to satisfy their curiosities. Furthermore, the level of the experiments which they performed and the knowledge they gained from them is quite high. It has been our experience that all students, from those with poor backgrounds, through the average, to those with very solid backgrounds in chemistry operate well, effectively, and do learn with the open-inquiry laboratories. The evaluation of the first goal (to acquaint the student with fundamental laboratorv techniaues and procedures) was carried out informally. ~ a b o i a t o r yreports were examined and in-class laboratory behaviors were observed. Through this informal evaluation we have become convinced that the students are gaining laboratory techniques and procedures a t least to the level of skill obtained with the more traditional verification laboratories. In order to evaluate the second and third .. eoals.. more formal techniaues were used to directlv compare thr ~i(lt.rl/~q,en-in(,~liry format with the verification format. Students taking Genernl Chemisrrv at the 1iniversitv of Oklahoma during tKe '76'77 academic year had inquir; format labs and will be referred to as the exoerimental erouo. Students taking the course a t Oklahoma state ~ n i v e r s i over c~ the same time period had verification format labs and will be called the con&l group. As far as we can tell, the students in these two groups and their academic experiences a t the two institutions are as similar as one can hope to achieve. Neither group was aware that they were taking part in an educational experiment. Thus, we assume that any differences in test results are in large part due to the different lab formats the two erouos exoerienced. piagetian-type paper and pencil tasks developed by the Cognitive Analysis Project (9) were used to measure the effect of lab format on intellectual development. Batteries of these tasks were administered to both the control and experimental graups a t the beginning of the first semester, a t the end of the first semester, and a t the end of the second semester. As reported earlier in this paper the entering freshman groups (-600lgroup) were hoth found to he about 14% formal, 78% transitional, and 8% concrete. T o compare growth in the two groups, students were matched according to these pretest scores. After one semester the experimental group showed a significantly larger gain in abstract thinking abilities than did the control group ( N = 133 for each group, statistical t test value = 4.71, probability that the difference occurred by chance
