A MULTI-SITE ANALYSIS OF TEACHERS’ PRACTICES ON THE “MOLE CONCEPT” FOLLOWING PROFESSIONAL DEVELOPMENT PROGRAMS
Malcolm B. Butler,
Our paper provides an account of teacher practices
on the “mole concept” following professional development in a non-western, less
inception of a new practical-oriented national science curriculum in all Kenyan
public schools in 1984, students' overall understanding of scientific concepts
seemed to decline each year as evidenced in their performance in national
examinations (Waihenya & Siringi, 2001).
Preliminary studies conducted by
The in-service teachers are expected to change their practices of using traditional methods of teaching chemistry to those of applying new pedagogical strategies/approaches through hands-on/minds-on and inquiry-based activities in teaching their secondary school chemistry classes (SMASSE Project, n. d.). This required appropriate and adequate preparations in planning, designing and implementing lesson plans that involve student-centered activities and the relevance of the chemistry learned to everyday life experiences. It was assumed that where conventional apparatus for experimental work is not available in school, the in-service teachers would improvise teaching materials using locally available resources. The in-service teachers work under various public school settings (rural, urban, boys’ day or boarding, girls’ day or boarding, and mixed day or boarding schools). They interact with other stakeholders in education such as parents, students, colleagues, school community members and local education officers. Such interactions are likely to influence the way the teachers prepare and conduct their “mole concept” lessons following in-service programs.
Social constructivist theoretical framework (Atwater, 1996; Schwadt, 1994; Staver, 1998) guided our study. Through social interaction, an individual shares knowledge with other people within his/her immediate community and wider society. Individuals continuously construct knowledge and new meanings as they make sense of their immediate environments. However, each person's knowledge structure is different from others because his/her life experiences and choices uniquely form each individual's knowledge.
People sharing similar cultural values and experiences are likely to perceive a given phenomenon in a given setting differently depending on their prior experiences and ways of thinking. This is likely to be true in school settings that serve students from given communities. Students in boys’ day or boarding, girls’ day or boarding and in mixed day or boarding schools are also likely to construct knowledge and new meanings based on their social interactions and environments. The students have to make a connection between the sciences they experience in their communities to that they learn in school. They have to move from the subculture of indigenous science knowledge to that of a western school science subculture. Teachers need to have an understanding of how their students can be helped to have smooth “border-crossings” (Aikenhead, 1998) into school science sub-culture and make sense of the "companion meanings" generated during classroom discourses (Roberts, 1998). The “companion meanings” may be in line with what they are expected to learn from the school science curriculum or they might be totally different from the intended ones.
Teachers need to understand their students’ sociocultural perspectives to enhance the teaching and learning of school science. Teachers’ cultural backgrounds and daily language at home are likely to affect the way they conduct classes during school science discourse. Continuous educational research on school science teaching and learning, based on social constructivist’s theories, is required to inform learners’ construction and development of scientific knowledge in rural school settings. This is important because teachers’ personal frameworks are likely to influence how they use a science-technology-society approach in teaching the “mole concept” unit (Case & Fraser, 1999; Dori & Hameiri, 2003; Furio, Guisasola, & Ratcliffe, 2000).
multi-site qualitative research case study (Stake, 1994) investigated chemistry
teachers’ practices in designing and implementing the “mole concept” unit
lesson plans following in-service teacher education courses in
How do the in-service teachers design secondary school
“mole concept” unit lessons in
How do the in-service teachers implement secondary
school “mole concept” unit lessons during instruction in
What changes in practice did in-service teachers make
when designing and implementing secondary school “mole concept” unit lessons'
4. What are the in-service teachers’ accounts of their classroom practices following professional development programs?
was conducted in
The study targeted in-service chemistry teachers in the pilot districts, the four in-serviced for each district at the national In-service Unit, and those who were in-serviced at the district level. It was assumed that each school had a chemistry teacher in-serviced, thus giving the pool of in-service chemistry teachers in each district to be approximately forty. Because of financial constraints, the study sample involved purposive selection of any two districts from the original nine in-service districts (convenient to the researchers in terms of transport and closeness of schools where the participants taught). Simba and Chui Districts were selected. Purposeful selection of participants (LeCompte & Preissle, 1993) was done to recruit high school chemistry teachers for the study. Based on the accessibility of participants' schools in the selected districts, we selected all the four chemistry teachers in-serviced by the National In-service Unit in Chui District and three in Simba District because one was deceased. One cluster in-service educator, educated at the district level, was selected in each district. This gave a total of nine in-service participants for the study. The purposeful selection of the in-service teachers who were still teaching chemistry ensured that the study participants are in the best position to provide adequate data that met the purpose of the study and would answer the research questions.
We used individual interviews (Kvale, 1996) and participant observation (Emerson, Fretz, & Shaw, 2001) methods to collect data from the selected in-service chemistry teachers in Spring 2004. We also collected archival data such as lesson plans, chemistry education syllabus, and the teacher's lesson notes for some of the observed sessions. Specifically, we interviewed the selected teachers using semi-structured guideline questions, individually and in focus groups (Gubrium & Holstein, 2002; Kvale, 1996). Each participant was interviewed before and after teaching his/her chemistry lesson(s) and observed more than once based on issues observed and emerging from the post-observation interviews. The participants were also requested to write a reflection journal of the chemistry lessons they taught during the research period and share their written accounts with us.
The interviews were audio-recorded. We went through the pre-observation conference audiotapes before the observation sessions to have a feel of the general themes, patterns and categories that we needed to explore during the observation sessions. We used the patterns or categories noted in our observation field notes as probes during the post-observation interview with the participants. Depending on issues generated during post-observation sessions and availability of time, we made more than one observation of each selected teacher teaching chemistry unit lessons during the first school term. We took field notes (Mishler, 1986) during observations which we then expanded during the fieldwork period. Some of the teachers' lesson plans for previously taught and the observed lessons, chemistry schemes of work/syllabus, and list of teaching resources (LeCompte, 2000) were collected during the interviews or observations. We then made copies of all data collected, put the field notes and interviews into a file and floppy disc based on participants and the dates they were created. A file on expanded field notes, lesson plans, teacher's lesson notes, and science education syllabus were kept. All the documents and artifacts were cataloged and stored. This process ensured that all the collected data was accounted for and retrievable whenever needed during the analysis.
We transcribed the audio taped data and typed our expanded field notes immediately after collecting data. With constant reference to the research questions, we grouped the codes into categories, patterns, and themes when interpreting the data using qualitative research procedures (Charmaz, 2002; Dey, 1999; LeCompte, 2000; Strauss & Corbin, 1996). We specifically looked for any relationships among the codes or categories. The developed relationships were summarized in the form of tables or figures followed by detailed descriptions and interpretation of the data.
Specifically, we used inductive data analysis strategies (Charmaz, 2002; Dey, 1999; LeCompte, 2000; Strauss & Corbin, 1996), employing open-coding techniques, to reveal regularities in the data. Inductive data analysis strategies that we found useful in our study include "pursuit of emergent themes through early data analysis and discovery of basic social processes within the data” (Charmaz, 2002, p. 677). Other helpful ones involved “inductive construction of themes that explained and synthesized the social processes, and integration of categories into a theoretical framework that specified causes, conditions, and consequences of the studied processes" (Charmaz, 2002, p. 677). In addition to appropriate use of traditional teaching methods, we expected the in-service chemistry teachers to prepare their lesson plans following the in-service format and teach according to in-service's PDSI (plan-do-see-improve) approach.
We started analyzing data using open coding strategies (Charmaz, 2002; LeCompte, 2000; Strauss & Corbin, 1996). The initial open coding helped us to start making analytic decisions about the data. During our data coding process, we studied the data before consulting any scholarly literature for theoretical themes, patterns or categories applicable to the data. We then labeled and organized the data using simple and general coding systems by looking for leads, ideas and issues in the data, and engaged ourselves in line-by-line coding (Charmaz, 2002). Through careful line-by-line coding, we looked for processes, actions, assumptions, and consequences in the data. We used active terms to define phenomena in the data and link specific statements in the transcriptions to the main processes that affected the participants' designing and implementing of ASEI chemistry unit lesson plans. Focused coding followed the line-by-line coding. During the focused coding process, we used the "most frequently appearing initial codes to sort, synthesize, and conceptualize the collected data" (Charmaz, 2002, p. 684). This assisted in generating several categories for the interview data.
process further helped us to establish the relative emphasis participants
placed on various issues regarding their experiences (LeCompte, 2000) in
teaching chemistry following in-service “training” programs. This made it
possible for us to develop the connections between participants' situations and
interpretations of their classroom practices. The data open coding was
triangulated through member checking. We used our colleagues' feedback and
initial open coding to do focused coding (Charmaz, 2002) in which we
categorized the codes based on participants' natural language and our research
interest. We also wrote elaborate descriptions of the categories (memos) and
integrated the memos (Charmaz, 2002; Strauss & Corbin, 1996) to reveal the
relationships between categories. This helped us to identify the themes
(LeCompte & Preissle, 1993; Ryan & Bernard, 2000) within participants'
told story on their practices in teaching chemistry unit lessons following
their in-service courses in
In this section, individual and focus group case
findings from the participants, with pseudonyms: Moja, Mbili, Tatu, Nne, Tano,
Sita, Saba, Nane and Tisa, who were teaching in different school settings
(boys’ boarding, Girls’ boarding, mixed boarding, and mixed day) in Simba and
Chui Districts, are presented. The participants’ class sizes ranged from 40 to
50 students, depending on the school category. District schools tend to have a
large number of students in class. In
The in-service teachers stated that lesson planning and preparation was hectic in relation to the materials required for students’ activities. But once the teachers had the required materials, the chemistry unit lessons are easily implemented. Moja said:
…you know the planning, the planning when you are preparing for a lesson, it is supposed to, it is hectic because you have to look for really materials for the students’ use in the activities. But once we have actually found this, it is now easier. It becomes easier for the teacher going into the class during the lesson than it has previously been.
Prior to the SMASSE project the teachers had a different way of planning their lessons. They would think of the class activities as the lesson progressed and using students’ responses, they made changes in class to cater for individual differences. As Tatu put it:
…you know before SMASSE, we used to plan in the class but once the lesson has started and you don’t have any plan that is when you come up with activities, that is when you open textbooks to get the [activities] and so on.
The in-service education had made the teachers to change their way of planning and implementing chemistry unit lesson plans. They had a new lesson plan format which the teachers felt was teacher friendly. They planned and identified the teaching and student activities early. The activities are logically organized to ensure that students have maximum learning opportunities during the chemistry sessions. Tatu said:
But now from SMASSE we have seen that you have to do planning early, you have to identify the activities you are going to carry out as a teacher. You have also to identify the activities the students are going to carry out and how they are going to be carried out and look for the materials. And also organize in a logical way in which you are going to carry out these activities so that learning takes place. Then also you find that now in SMASSE, we managed to come up with a format of a lesson plan which makes the planning easy. Format we start for activity and teaching/learning points or teaching/learning notes and remarks. You see this format is teacher friendly. It makes the teacher really plan very easily rather than the old one which was lengthy.
Mbili added “because of this SMASSE…I have found it now difficult to go to class without, you know, at least having even if I don’t have that detailed planning, at least I have identified some activity that I will give to the students.”
The in-service teachers are able to make changes during their lesson planning and implementation. However, to some extent, they find lesson planning using the in-service format requiring considerable amount of time. However, once the lesson plan is made, its implementation is teacher friendly. The students have activities to perform while the teacher assists them in their learning processes. This was a big change for the teachers, who used to teach using lecture method, give student notes and class experiments depending on the availability of resources or teacher’s enthusiasm in having his/her students perform class experiments or have a teacher demonstration. In this regard, Moja said:
You know when you don’t have activities for the students you find during the teaching of the lesson you are actually doing a lot of work. You find like I was cracking a joke last week a teacher came to the lab and he was still on chalk. That one is hands-off that meant that actually the students had no activities except to wait the writing on the board. So when you are preparing according to the SMASSE, in the preparation part it is not teacher friendly but when it comes to class now during the implementation of the lesson it is quite teacher friendly because much of the work is done by the students. So that is the much which has really assisted in preparing the lesson and disseminating the same knowledge in class.
Mbili concurred with Moja that following the in-service education lesson plan format, their chemistry unit lesson preparations had become effective. The students enjoy the chemistry sessions because they are involved in learning activities. As Mbili put it:
…You know when it comes to the preparation, yes it is effective but when you go to class, you find that the students will [use] because you have already identified the activities and then at the same time, you know the students enjoy it. And the students they want you know sometimes learn this and you go to class and you don’t want to talk, talk, talk, you know you find that they are bored. So I think that is true....
However, Tatu was worried of those students who might not be doing the hands-on activities during the teacher demonstrations or group activities. He said:
…I have come across one problem in carrying some of these activities because you find that if you have to use the students what I have [been] wondering is that these students who are participating in the activities you know they are not with the rest of the students to watch what you are doing. These ones you are using are they learning?
According to Mbili, Tatu’s concern was not a problem because one can be choosing on different students during different lessons. Mbili said:
…I think it is okay because when you use them at that time you know you are not using throughout you know that is one activity, then there you choose another group…And remember when you do something actually is when you remember it more. So these students are even more advantaged than the ones who are just looking on because these ones will remember exactly what they did.
Involvement of different students during the teacher demonstrations ensures that more students participate in conducting the experiments in class as opposed to them being spectators. Mbili had the teaching learning metaphor of “when you do something actually is when you remember it more.”
Planning and implementing lessons on the “mole concept”
The participants felt that the topic on the “mole concept” scares students, right from the start. However, the participants were able to address the students’ fears by not telling them that they were starting the topic on the “mole”. The students come to learn later that they are studying the “mole concept” as they discuss basic units in their daily life such as a dozen, then relate to the “mole” as a quantity of material equal to 6.0X 1023 particles. On how to introduce the topic of the “mole concept”, Mbili said:
Now this topic, the “mole concept”, scares students right
away I don’t know for what reasons. But any time you know they know they are
going to start the “mole concept” you find really, you know they are scared.
So, personally, what I have done when I am starting the topic of “mole concept”,
I don’t even tell them that we are starting the topic of the “mole concept”.
They come to learn much that we are now doing the “mole concept”. So naturally
or usually when I start that I start by just giving them we discuss the unit
you know the basic units that are used every day and then you if it is a dozen,
twelve items. If it is a pound these many items when you are talking about
The participants concurred that the “mole concept” was very important in volumetric analysis experiments on titration. Many experiments have to be done to enhance student understanding of the “mole concept”. According to the participants, students ought to perform an experiment at least every week and calculation activities given to reinforce students’ understanding of the “mole concept” in titrations, for example, converting a given mass into moles. Tatu commented:
Of course in the “mole concept” is where we get the necessary information to carry out volumetric analysis experiments on titration and so on whereby they are able to count the particles are in a large scale. I think here to enhance the student understanding you have to carry out a number of practicals. So there must be enough experiments therefore the students to carry out starting with simple ones and to the more difficult ones. And the experiments should be carried at least every week. We should not carry them out only at that time we are starting the mole, let’s say at the beginning of Form three, then after that we stop completely and end up meeting them in the exams. So to remind them about the concepts covered in this topic, the “mole concept”, there must be at least an experiment in a fortnight at least one.
Practice questions also assist the students to know how to apply the “mole concept” to particles involved in chemistry such as atoms, molecules, and ions. When students are assisted to master calculations involving the “mole”, they enjoy participating in experimental work on titrations and easily solve advanced “mole concept” problems. As Moja stated:
..In my case I really find it the activity I normally give here mostly goes with calculations where from the “mole” for the students to do very well in titration, they must understand what a “mole” is. And for example can they convert a given mass into a number of “moles”. If they can not convert the number of given grams into “moles”, then even if they were given the titration it becomes extremely difficult for them.
The in-service teachers found one of the recommended secondary school textbooks quite relevant in preparing their students on calculations on the “mole concept”. They said that textbooks had a variety of “mole concept” problems that help students understand the topic well and how it is applicable in their everyday life situations. As Moja said:
So here I have specifically emphasized the use of Patel
book three (referring to a Form three chemistry textbook written by Patel which
is used as one of the secondary school chemistry-class textbooks in
Student activities are emphasized in the participants’ “mole concept” classes before they embark on practical sessions on titrations. Students’ prior knowledge on how to convert a certain mass of particles of a given substance into “moles” and vice versa is a pre-requisite to the titrations problems they have to solve during practical sessions. The students are made to understand that a “mole”, as a unit of measurement, is a very large unit that we don’t even have a “mole” of people on earth, but it is possible for small particles found on earth. Moja said:
So that part which is basically having activities in the form of calculations is where I emphasize so much before I go to giving them a lot of practicals now on titration. And there is also one joke which I normally have when I am looking at the “mole” and Avogadro’s, you know you sometimes wonder whether the word has one “mole” of people (laughter). If the world can not produce even a “mole” of people, the whole world because that Avogadro’s number, you know, is so big that the world can not have a mole of people.
The students are guided to understand how a “mole” is applicable to various particles covered in chemistry such as the electrons, atoms, molecules and ions. They have to know the relationship between Avogadro’s number and the “mole” of particles under review. In Moja’s words:
So I normally make them understand that when we are talking of a “mole”, it should be a “mole” of any substance so that they don’t expect that if I calculated a “mole” of ions, then when it becomes to “mole” of molecules it will not be a “mole”. So they know that anything that can give out Avogadro’s number of particles should be referred to us a “mole”. So here the calculations are very, very important as the activities. And they must be followed and be given in a plenty of them for the students to understand.
The teaching of the “mole concept” is being simplified through use of films and videos on reactions involving the “mole concept”. According to Tatu:
There are these films that are available like from SMASSE, like the film on the “mole concept”. We are able to weigh a “mole” of ions, atoms and they are able to see that that is a “mole”, Avogadro’s number of atoms or ions. If you have the facilities we can also show them the films on the “mole concept”.
From the participants’ accounts, it is evident that students benefited from the “mole concept” lessons that were introduced based on the students’ practical experiences and the volumetric analysis experiments on titrations. The students understood the “mole concept” better when they are given opportunities to solve “mole concept” questions in class or as assignments. From the observed class sessions on the “mole concept”, it was evident that the students’ work was reinforced by the continuous lesson evaluations the teachers had adopted as a result of the SMASSE in-service education courses.
changes that the participants had made was the incorporation of the ASEI
movement in their lesson planning and the PDSI approach in their chemistry unit
For one previously we never used to assess our lesson with intention of improving the next lesson but now we do that. In our lessons now we have to plan for it look for the materials required and not that particular moment during the lesson that we are running up and down to arrange this and that but we put them ready in advance.
The in-service teachers make changes on the learning activities. The lesson activities are learner-centered. Sita had a teaching metaphor on how to involve students in chemistry teaching. He believes that as students participate in various learning activities, the teachers should “let the child do as the teacher sees.” This is a great change from the teachers’ demonstration classes they mostly used to have whenever they conducted experiments in class. As Sita said:
…let me have this one as “let the child do”, that should be heading, the PDSI approach is actually sort of “let the child do as the teacher sees” unlike previous times when we were carrying out experiments by ourselves demonstrating. This time we have the child or the pupil involved.
The student-centered chemistry lessons are teacher-friendly. The teachers are able to teach any part of the curriculum as they improvise the teaching and learning materials using locally available resources. Sita said:
And our lessons are a bit friendly because sometimes teachers can fear going to handle like a double lesson, depending on the nature of the topic and the available apparatus or equipment. But the inclusion of this SMASSE, the PDSI approach and with the ASEI lesson plan always ensures the lesson is very friendly, the student is there [to be taught and learn], they can use the local materials, [which] we don’t go to purchase.
The lessons are teacher friendly because of the student-centered activities. The students fully participate in the learning activities while the teacher plays a role of a supervisor during the chemistry sessions. As Sita expounded on how the changes they made in their chemistry lessons were teacher friendly, he noted:
Being friendly in the sense that there is this ASEI activity for the student, an activity which the student must be involved in the experiment, more experiments, at least every student, you divide them in small units, they are able to do those experiments and from there we improvise. In fact in the improvisation they should be involved. So, in most of the cases it is the student who is just doing the experiment, here you are to supervise and therefore you don’t strain”, you don’t talk a lot, they do a lot and give you the [measurement] you talked of and you find you are comfortably moving with the lesson.
The teacher’s role, as a supervisor, during student-centered activities means that students are left to perform inquiry-based learning on their own. The teacher is there to ensure that the students participate fully in the learning activities and is there for those who need assistance. As Sita said:
In the PDSI we have the planning, the doing, and the see. These are involved in the planning from the aspect of the teacher, the doing is from the aspect of students involved, and the teacher is there as supervisor. But then the seeing, the students are involved to see what they are doing, and then from there you improve.
In addition to what Sita thought,
was the teacher’s role during the student-centered learning activities,
I think the seeing aspect is also the evaluation. It brings the evaluation aspect, whereby you are able to evaluate your students, whether the students have understood and even as the teacher under the planning and doing section, the teacher can equally evaluate himself whether did the things go as per the plan during the process of implementation and they help us to improve later in our next lessons.
other hand, Sita’s assertion on the use of locally available materials in
preparing teaching and learning aids was supported by
Alongside that in the ASEI lesson plan, the area of improvisation is really emphasized and we are now using local materials in a situation where we don’t have the equipment or facility required. And I think in one way we are helping our students much better. So our approach to teaching, the teaching of chemistry has changed for the better.
The use of locally available materials in the teaching of chemistry units had eased a financial burden on schools that had to buy conventional materials for teachers and students’ use. The changes made in the planning and teaching of chemistry unit lessons had somehow lead to a healthy relationship between the heads of institutions and their chemistry teachers. As Sita put it:
The head of the institution is very comfortable because sometimes it makes even the head of the institution frustrate the science teacher in handling of the lesson during the teaching process, during the acquisition of the materials. But with this improvisation, the ASEI lesson plan, it helps bring out some of those problems. It caters for that and therefore the teacher is able to handle the lesson very nicely without any problem and at least not financially strenuous because you are in most of it is improvisation.
The changes teachers make in their planning and teaching of chemistry units following the in-service programs are likely to benefit the interior rural schools which are poorly equipped with resources for science. Sita, further, stated:
And some of our schools especially which are in the interior, which are not so developed, we have a lot of these materials, all kinds of plastics are there to use. So, you find a topic like organic chemistry to handle it there is so comfortable. So, I think you find the approach so good because of this SMASSE program.
From the participants’ views, it is evident that the changes they make in planning and implementing their chemistry unit lessons are teacher friendly and assist students to learn better in many rural schools. The new format of lesson planning and implementation reduces the schools’ financial obligations in providing the conventional materials for science teaching thus likely to make school heads and in-service chemistry teachers to have a cordial relationship.
Planning and implementing lessons on the “mole concept”
The participants thought that the “mole concept” was a wide topic that needed to be approached carefully to benefit the students. As a number, the “mole’ should be approached from the counting concept. The counting should be based on students’ familiar items. As Sita said:
…the “mole concept” is a bit also wide…because mole, the idea of moles, we are talking of a number and therefore we might begin with counting. And what are you going to count? We are going to count atoms, electrons, ions and molecules. And we can explain it further. We can count even beans, the local things which the students are familiar with and before you approach the actual lab because most of our students, those who are below average will get the concept very well if you bring it home to the familiar things which can be counted.
The idea of counting was extended to proportionality of other units of measurement such as meters and mass units such as grams. Sita stated, “through that counting you can easily now bring the idea like say we have one kilometer is a thousand meters and therefore how about how many kilometers do we have in 300 meters?” Students are then made to convert given masses into moles, as a unit of measurement equal to the Avogadro’s number (6.0x1023) of particles. With many activities for students, the “mole” becomes an interesting topic. The students are exposed to the “mole” of particles such as electrons, atoms, molecules, and ions. Sita said:
Then we are trying to bring the idea of converting grams to moles. And therefore the Avogadro's number coming in because, that is a number, 6x10 to the power of 23. And you relate it to one kilometer is a thousand meters and one mole is therefore this number of particles. So the “mole concept” is a very interesting topic and you can have so many activities for the students to actually take part.
Saba used analogies that involved the students familiar counting units such as dozen and gross before defining a “mole” as a unit of measurement equal to 6.0x1023 of particles . He said:
…I also would like to add that the same analogies can be used, like for instance, dozens standing for 12 items, a gross standing for 144 items. And we can say a “mole” also stands for a particular number of particles, which has got the number of particles 6.0 x 10 to the power of 23. The existence of particles, for the student to know that which particles we are talking about here, the particles can be electrons they can be ions, the molecules.
According to Nane, the “mole” should be introduced without the word “concept”. When the two words are used together they confuse students with an impression that the topic was difficult to study. As Nane put it:
…I could add that the “mole concept” being a very wide topic; now give to students with problems especially the idea of the “mole concept”. So I don’t know whether we could change this one and have it as the “mole” that we don’t include the ‘concept’ so that when we talk of the “mole” to look at it as a unit of measurement. And when they realize that it is a unit of measurement of course now they will relate it to what they use as centimeters, meters, kilometers and other things.
Another way that the “mole concept” is introduced is through student activities to compare the capacity of a set of two apparatus, that students are familiar with, such as beakers (of different sizes) and items such as sand. The students are to find how many small beakers of sand are to fill the bigger beakers. Nane said:
Then of course, the introduction sometimes you can introduce it using beakers, for example of different sizes, you fill the small beaker with sand for example and try to know how many of these beakers containing sand will go to the bigger beaker. So that at least they use a small beaker as a reference but the smaller unit that we could have.
of having electrons in atoms is sometimes abstract to many students. To start
dealing with a “mole” of electrons becomes more abstract to this group of
students. The existence of electrons is demonstrated using locally available
materials such as two inflated balloons.
As far as electrons are concerned, two inflated balloons can be rubbed against hair and later it is found that that these balloons start repelling one another implying that the surfaces contain now a similar kind of particles and that is why they are able to repel. And this one helps students to know that electrons actually exist.
The existence of particles in solutions is demonstrated using colored substances such as potassium permanganate. The dilution effect on dissolved potassium permanganate assists students to understand that ions can also be counted. According to Sita, “dissolving of colored substances such as potassium permanganate, whereby the color is able to spread to various parts of the container, will be able to show the students that matter is actually continuous.”
Based on a previously observed lesson on dilution experiment, Sita was asked to comment on why his approach in teaching the “mole concept” was different from the rest of his colleagues. The way one plans and implements a “mole concept” unit lesson depends on the type of students one has and the type of counting the students have to do. In his lengthy response, Sita said:
My approach is basically counting because here is a case where they are trying a dilution experiment. Diluting potassium permanganate, they are trying to count. Probably with more dilution the last color or color disappears, and then from there we do an estimate. It is a form of counting now here we are counting the ions. There are cases where we are counting the actual particles like counting atoms, counting the beans, you are not counting ions, we can even put on the word atom, and we are counting the atoms. Actually what I was trying to bring about was that as much as we know of atoms, I was bringing the ions issue. So that the idea that matter consists of particles, smaller particles, is passed to students very well that as much as there is a crystal, there are smaller particles and can we count smaller particles? Yes, through dilution. That is how I may do it. There are approaches, various approaches, my friends are right, that is another way, their approach is correct, and it can bring the sense. In fact you weigh the type of students that you have. Our students, I think there are some who are above average, you can have a class, which is slightly just average, there your approach must use is to "come down" so that the message is clear. There are cases where you have a class, which is slightly above average. That class, you find even the way they ask the questions, you “trained” as a teacher, it is a question, and as a “trained” SMASSE teacher, you would be able to weigh. And then tackle the question, which will improve the method that is why we were saying about the ASEI, the PDSI, Plan -Do -See and Improve.
that teachers exposed students to movement of ions is based on simple
experiments on electrolysis processes. These simple experiments also help
students to understand that the ions too can be counted like any other
We have the, trying to expose students to ions by carrying out some simple electrolysis, trying to exposes students to movement of the ions itself as we are exposing students to know that they are ions and therefore they can be counted as well.
on the “mole concept” are found useful in assisting students to understand the
ideas on the topic. The participants planned for student activities on the
“mole concept” calculations. As the students solved the “mole” related
problems, they were able to appreciate the applicability of the topic in their
everyday lives. The calculations were followed by discussions under the
guidance of the teacher. The teacher did continuous lesson evaluations during
these teaching and learning activities. As
On the “mole concept”, so far it happens to have a lot of calculations in the name of solving problems, so one way, is to involve students in the calculations and then discussing all those after the calculations. In line with the ASEI movement, in the “mole concept”, students can really be involved in calculations and such kinds of activities. But then, at the end of such a lesson evaluation can be done on areas, which students maybe found difficult or something like that. So that they are able to exchange views with the guidance of the teacher and [with this] for the subsequent lessons the teacher is able to make amendments as a way of trying to improve on the lesson.
Nane felt that students have to be given simple “mole concept” problems to solve before they are introduced to more complicated problems. He said:
So in that case with all the calculations, they will always have problems. And this one of course, they have problems because they have a problem in the imagining. So these boys or girls who have problems in calculations, you need to give them simple questions on calculations so that once they do them they could be induced to do more of these problems.
The students were found to be having problems in solving calculations relating to the molar or formula masses. The teacher had to tell the students how the molar or formula masses were obtained. As Nane put it:
Then, the problem usually I get is that of relating the formula mass or the molar mass to the calculations, how is it that, like now, when you talk of let’s say sodium hydroxide, it’s a molar mass is 40 grams. We talk of it as a molar mass but in essence it is not easy for one to relate how this mass is obtained. So maybe you have to tell them that these are arbitrary numbers given to these atoms so that when they are added together you will get the mass, like now the atomic mass is in grams, etc. So that they use those masses, and given, like now, these 40 grams is the mass of one mole of sodium hydroxide.
Sita concurred with Nane that students asked questions about the formula and molecular masses. The students were asked to identify the number of atoms found in a given chemical formula. According to Sita, the students are assisted to solve the “mole concept” related problems when they are reminded about the formula or molecular masses and how to determine them from given information. By so doing, the students were able to follow and solve the “mole concept” problems with ease.
Although the in-service teachers had enhanced teaching skills, lack of finances to provide adequate teaching/learning materials hinder their teaching of the “mole concept” in rural schools. The situation becomes worse in places where some principals are uncooperative towards in-service activities because they feel that the chemistry activities are becoming rather expensive for the schools to implement. The school heads and participants’ colleagues still prefer traditional methods of teaching chemistry to that advocated for by the in-service programs.
frequent curriculum reviews require new textbooks, while many teachers practice
examination-oriented teaching. The teachers’ rewards in
The district in-service resource centers help many schools which lack apparatus or chemicals to borrow them for a given duration. However, teachers’ laxity to return borrowed items to the district in-service education centers inconveniences others who want to borrow them for their schools. There is need for the national in-service office personnel to support the formation of district chemistry associations for the teachers to exchange ideas applicable to their school situations. This is likely to lead to proper management of district in-service funds to facilitate adequate provision of chemistry teaching materials in schools.
There is need to have further research to find out whether the students taught the “mole concept” by the in-service teachers had an advantage over their counterparts taught by those who do not attend organized in-service teacher education programs. This study only focused on teachers’ lesson planning and implementation of the “mole concept” following their in-service courses. There is also need to find out whether the in-service teachers plan and implement their “mole concept” unit lessons differently from those who do not attend the in-service teacher education programs.
These findings suggest that qualitative research methodologies are effective in establishing in-service teachers’ accounts of their practices when teaching the “mole concept”, some of which cannot be generated using quantitative methods. It also seems that participant-centered in-service programs, involving stakeholders in decision making, are likely to be very effective in enhancing teachers’ skills in teaching the “mole concept” unit. Stakeholders’ participation in professional development seems to influence in-service teachers’ classroom practices. This calls for policies on effective professional programs to promote student achievement on the “mole concept” unit and enhance teachers’ classroom practices in chemistry teaching and learning.
Our findings suggest that the “mole concept” is one of the topics that high students have most apprehensions. However through in-service teacher education programs, the teachers are able to organize relevant activities based on students' every day experiences to enhance their understanding of the topic. Students should be given more practice in calculating "mole" related problems before they start titration experiments.
The in-service teachers are able to address the students’ apprehensions by not telling them that they are starting the topic on the “mole”. The students learn later that they are studying the “mole concept” as they discuss basic units in their daily life such as a dozen, then relate to the mole as a quantity of material equal to 6.0 x 1023 particles.
The participants concurred that the “mole concept” was very important in volumetric analysis experiments on titration. Many experiments have to be done to enhance student understanding of the “mole concept”. According to the participants, students ought to perform an experiment at least every week and calculation activities given to reinforce students’ understanding of the “mole concept” in titrations, for example, converting a given mass into moles. Practice questions also assist the students to know how to apply the “mole concept” to particles involved in chemistry such as atoms, molecules, and ions. Where applicable, some participants showed their classes films on the “mole concept”. The films helped students to visualize the “mole concept” which they sometimes found difficulty to learn.
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