They also enjoy working in a group so that the work may be shared. (Miss Essop, interview)
Miss Essop was also asked about how predominant this approach was in her teaching. She remarked that as far as possible, learners were given the opportunity to do investigations which were open. However, due to the time constraints and the pressure of covering content, most of the investigations in her class were guided.
The learners who were interviewed from this class corroborated what the teacher had said about the enjoyment which they derived from doing the investigation on their own. The following comment by a learner from this class supports this.
Science used to be a real drag last year. It was boring watching the teacher do the
experiments and stuff. This year I find science more interesting because we can do things on our own. (Learner interview, Miss Essop's class)
The investigation described in Miss Essop's class would be classified as a typical open investigation according to the framework being used.
had eight Natural Science classes in Grade 9, and the learners were graded according to their academic ability. The class observed was the `B' class. Mr Botha has fifteen years' teaching experience in Natural Science and Physical Science. It was his third year teaching at this particular school. He possesses a Bachelor of Science degree with majors in
mathematics and physics, and a higher diploma in education.
The lesson observed took place in a science laboratory. There were seven tables, each designed to accommodate four learners distributed throughout the laboratory. Before the lesson, the teacher explained to me that it was going to be an investigation on electricity.
The learners had the task of practically identifying all factors which affect the resistance in a circuit. It was the third practical lesson on electricity. In the two previous lessons. the learners had dealt with current strength, resistance and potential difference. They had drawn circuit diagrams and connected circuits. The teacher told me that the learners from these lessons had gained sufficient expertise to connect the components in an electrical circuit. The learners had been working in groups of four during the previous practical lessons, and they would continue in the same groups for this lesson. When questioned about the composition of the groups, Mr Botha explained that he had nominated six responsible learners as group leaders and they then chose the members in the groups. He told me this was the best way to get groups where all members 'got along' and worked harmoniously.
The length of each teaching period was 50 minutes. However, for the observed lesson the teacher informed me that he had made arrangements with the mentor teacher to also use the mentor period (thirty minutes) for the investigation. The investigation lesson would
therefore extent for one hour and twenty minutes.
4.2.2 A description of what happened in Mr Botha's class
At the start of the lesson, the learners organized themselves into groups at their tables.
After greeting the learners, the teacher drew the attention to what was written on the board:
"Task: To identify factors which affect the resistance in a circuit." The teacher then initiated a class discussion on electrical resistance. He asked the learners, "What do we understand by resistance ?" The majority of the learners almost instantaneously raised their hands. The teacher pointed to a learner who answered, "difficulty of flow." The teacher
nodded his head and pointed to another learner. This learner explained, "something which opposes the flow of charge." The teacher asked, "Do you all agree with this definition? - The class answered almost in unison, "Yes sir".
The teacher then questioned the class about the ammeter and what it was used for. Through further follow-up questioning the class came to realize that the ammeter reading could be used as an indicator of resistance in the circuit. From this class discussion, the learners learnt that the lower the ammeter reading, the higher the resistance in the circuit. Mr Botha told the class that they had the task of discovering the factors which affected the resistance in a circuit. He explained that they were to investigate as many factors as they could in the available time. He handed out a worksheet with guiding questions on them (Appendix G).
The worksheet included the following:
1. I think this will affect resistance 2. How will I investigate it ? 3. How does it affect resistance ?
The learners were expected to answer these questions for each of the factors they were going to investigate.
On the instruction of the teacher, the group leaders collected the electricity packs from the teacher's table. The groups were instructed by the teacher to brainstorm ideas and then devise a plan of action. They were required to write down this plan on the worksheet provided. During these group discussions, the teacher walked about the class and listened in on the exchanges between learners. After a few minutes he went to each group and asked them to describe their plan. In this exchange, he asked many questions, and these questions forced the learners to reflect very carefully on their plan for the investigation.
The following excerpt illustrates this questioning:
Mr Botha: Okay, I see you guys have chosen thickness of conductor as a factor which would influence the resistance. Tell me, why have you chosen thickness ? John: We are all pretty confident that if you increase thickness it will make it
easier for the current to pass through.
Mr Botha: What about the resistance ?
Justin: It would therefore have less resistance.
Mr Botha: Good. Now explain to me Kajee, how the group intends investigating this.
Kajee: Sir, we decided to make it easier for the charge. We must offer it another path. The light bulbs must be connected in parallel.
Mr Botha: So are you saying that thickness equates to having resistors in parallel.
What if you had three in parallel.
Kajee: It will be more thicker.
Mr Botha: Okay, how will you show this relationship between thickness and resistance.
[The teacher looks at Sooriah.]
Sooriah: Use the ammeter.
Mr Botha: Tell me more.
Sooriah: Connect the ammeter in the circuit to measure current strength.
Mr Botha: Yes, but how will this enable you to investigate resistance ?
[Sooriah does not answer and shakes his head. The teacher then redirects the question to John. John answers.]
John: A higher reading means smaller resistance.
Mr Botha: Okay, do we have that ?
The teacher adopted a similar questioning technique with the other groups. After getting the go ahead from the teacher, the groups then proceeded to open the electricity packs and began connecting a circuit. In a short time, the room became very lively. There was lots of cross-talk both within and between groups. I observed that three groups investigated length, two groups investigated the thickness of the conductor, and one group investigated the type of metal as a factor affecting resistance. I heard exchanges such as the following taking place within the groups:
Both light bulbs should come on. What's happening ? Where's the current going ? Check the circuit. There must be a gap. It could also be the battery."
At another table:
Something is wrong with the ammeter. The needle is wrong. What could this mean ? Reverse the red and black wires. The current is going the other way.
The teacher interacted with the groups and asked questions and offered advice when
necessary. On one occasion I observed the teacher returned to the group, where the learners were investigating the thickness of the conductor as a factor affecting resistance. The teacher looked at the circuit the group had connected. The teacher then questioned the learners about the circuit.
Mr Botha: Tell me what you have done so far.
Kajee: We first took one light bulb and measured the current passing through. We then decided to increase the thickness by having two light bulbs in parallel.
Now we want to measure the current strength.
Mr Botha: Can I have a look at your circuit diagram for this ?
[The group produces a circuit diagram which they had drawn in the planning stage of the investigation. It was a diagram where there are two
light bulbs in parallel, and an ammeter in series with one of the light bulbs. The teacher continues with his questioning.]
Mr Botha: I want you to look carefully at your circuit diagram you have drawn and the one you have connected. Are they the same ? Trace the flow of current.
Is it the same Justin ? Justin: Yes sir.
Mr Botha: Look at the position of the ammeter. What is it measuring in the connected circuit.
Kajee: The current passing through this light bulb.
Mr Botha: Is that what you want ? Yes, John, John: No, I think we need the total current.
Mr Botha: Good. Do you know what needs to be changed in the circuit.
[The learners answer 'yes'. The group then reconnects the circuit with the ammeter in series with the parallel combination of resistors.]
Mr Botha interacted in a similar way with the other groups. He constantly walked around, checking that the groups were making progress. He asked questions, and made suggestion when deemed necessary. With the teacher's guidance and facilitation, each group appeared to be on the right track.
Ten minutes before the end of the lesson (they had been working for 60 minutes) the teacher asked the groups to stop working. He quickly ascertained that each groups had investigated at least one factor. The teacher then asked each group to give a report back of what they had learnt through the investigation. Each group then shared their findings with the rest of the class. The groups explained how each factor affected the resistance in the circuit. For example, one group stated that as the conductor becomes longer, the resistance increases. The groups which had investigated the same factor arrived at similar findings.
After each group had given a report back, the teacher summarised their findings on the board.
4.2.3 Follow-up on lesson in Mr Botha's class
The learners were asked to design an investigation to identify the factors which affected the resistance in a circuit. In the planning stage the learners decided on what factor to investigate. They then formulated a hypothesis based on this. The learners were
responsible for carrying out the investigation and collecting data. They drew their own conclusions. The teacher facilitated their progress through the investigation. The class discussion at the beginning of the lesson orientated the learners towards the investigation.
Without telling them directly, but through skilful questioning, the teacher guided the learners to what resistance was, and how the ammeter could be used to indicate the relative amount of resistance in the circuit. In the planning stage where the learners decided on the factor they would investigate and how they would go about doing it, the teacher was always on hand to ask a clarifying question or to offer a suggestion to get the group on track. When the learners were carrying out their plan and collecting data, the teacher was again present in a supportive capacity.
In the interview which followed the investigation, Mr Botha was questioned about the role which he had played during the investigation. He described himself as a guide who would provide direction to the learners in leading them to the desired outcome. The teacher described this role as follows:
As you can see the learners did a lot on their own. But they were not left alone. I was around to make sure they were on the right track. I guided them throughout the
investigation so that they moved in the right direction. (Mr Botha, interview)
The learners who were interviewed all commented positively about their experience of conducting the investigation on their own. A learner interviewed expressed this viewpoint as follows: "We liked playing around with the circuit. It was great fun as we could try different things and change the parts if we liked. This was much better that just looking at the diagram."
The lesson in Mr Botha's class illustrates a guided investigation where the teacher decided the topic and provided the investigation question. The learners then planned the
investigation, collected data and drew their conclusions mostly on their own.