A portrait of Sunny

Sunny was a Grade 5 boy who initially chose to investigate “Solar panels”. Table 4.4 contains the transcripts of Sunny’s three videos.

 

Table 4.4

Sunny’s video transcripts for “Solar cell efficiency”

Prior knowledge video
Transcript

My topic is solar panels and what I know about them is that they take something from the Sun and make it into energy that can power stuff like, umm, and, it saves you money on electricity bills.

And that's most of the, no that's all of the stuff I know about solar panels.

 

 

Completed explanatory animation
Transcript

Solar panels are made up of photovoltaic cells.

A photovoltaic cell converts light energy into electricity.

At the heart of a photovoltaic cell is an NP junction where negative and positive plates made of silicon and other materials are placed close together.  Electrons want to jump across from the Negative to the Positive side.  This force is known as voltage but energy is still needed to make electrons jump across.

Energy in the form of photons from sunlight enables electrons to jump across which creates the flow of electricity, which is known as current.

Even the best solar cells only achieve around 40% efficiency.

There are several things that can improve the efficiency of solar cells:

Silicon is very shiny so most of the sunlight is reflected which is a waste of energy.  This is why solar panels have a dark non-reflective coating so that more light flows into the cell.

Light can have different amounts of energy just like it can have different colours.

Most solar cells are designed to create electricity with only a small amount of light but this means that only a low voltage is produced.

The strength of the voltage known as 'Band gap energy' depends on how much energy is required for electrons to jump across the NP junction.

In strong sunlight you get extra current but the voltage doesn’t really increase. New research involves multi-junction cells which have more than one electric field.  This allows the panel to operate in low light and also take advantage of stronger light with increased current and voltage.

Director's commentary
Transcript

Halfway through my animation I slightly changed my topic from "Solar panels" to "Solar cell efficiency".

Originally I had an idea of a stadium, or a theatre of some sort, and electrons jumping from one seat to another because someone had moved to go somewhere.  After I changed that we made it more realistic with electrons jumping across from one bar that said "Negative" to one bar that said "Positive".

To make the animation about solar cells, I had to learn about other things like voltage, current and electricity, which I only knew some about at the start of the animation.

I figured out that the solar panels are dark because, if they’re not, the light bounces off and when it’s dark it gets absorbed so the energy isn’t wasted.

In real life the band gap energy doesn’t mean that the negative and positive sides are further apart (like it looks like in the animation) but that was a good way to show it so that people would understand.

My topic was so complicated that, although it’s still the longest, we had to remove some of the information that we were going to include at the start.

 

Introducing Sunny and his topic

Sunny was one of the youngest participants in the current study but he was also very capable and articulate. As a researcher, this allowed me to focus on where he was going with his ideas rather than trying to interpret what he was saying.

Sunny had defined his topic as “Solar power” during our initial discussions leading up to the first session. During the first session, his topic changed to “Solar panels” to shift the focus onto how solar panels worked as the benefits of solar power were self-evident. Sunny’s prior knowledge video still had echoes of the solar power theme with his reference to saving money on electricity bills. Sunny eventually changed his topic to “Solar cell efficiency” towards the end (1) of the project.

 

Creating the ZPD with Sunny

I found Sunny’s topic to be the most difficult out of the eight topics that the children chose to explore. My own understanding of the children’s eight topics was expanded throughout the project, but it was my collaboration with Sunny that was most characteristic of a “mutual zone of proximal development” (John-Steiner, 2000, p. 177) as I was learning alongside him throughout the full two terms.

Our conceptual journey together and the difficulties that we faced seemed related to specific content knowledge for the representation of electricity. Beaty (1995) noted that children are often presented with incorrect or simplistic information regarding electricity due to the inherent complexity of the topic and the perpetuated misconceptions held by many teachers in both primary and secondary school settings. Hence, guiding Sunny within the ZPD was particularly difficult for me, as I had reached the limits of my own understanding for this topic. I grappled with this situation and documented it in my reflexive journal:

After today's session I was further examining my role in this whole process, particularly with assisting the recording of the student reflections. Sometimes the children don't know what to say because they're not sure where their research is heading. This is part of the "you don't know what you don't know" dilemma. In such cases, I'm more like a coach where I provide encouragement and guidance. For some topics like "Solar panels" I am equally mystified (Researcher’s reflexive journal, 20th October 2011).

Perhaps the progress of Sunny’s project was also hindered by the fact that he missed two out of the sixteen Storyboard sessions. He would have missed four if I hadn’t arranged private make-up sessions with Sunny on two occasions so that we could finish the project. We discussed the dynamics of this during the debriefing session with the other students. Molly was correct in surmising that the class-of-one with Sunny was awkward. If ideas had been flowing between Sunny and me then it wouldn’t have seemed awkward. But because we both were completely stumped, our reflection turned into an overtly self-conscious pursuit:

Brendan: There was a session with "Solar cell efficiency" [Sunny] where it was just one person because he missed a few and it was just you and I [Sunny and Brendan]. That was almost a little strange, just one person [rather than the full group]. Not a little strange but it was...

Molly: [speculating] It was awkward.

Sunny: Didn’t we have two of those sessions?

Brendan: We had two of those sessions. Often I didn’t give you time to just think. I think it’s...a small group’s perfect ‘cause then I can give you attention and then leave you alone for a bit to, to think (Debriefing session 1C, 15th December 2011).

The ZPD that Sunny and I were in was clearly a mutual zone as we were both working at our outer limits of understanding, simultaneously. Towards the end of this session, I encouraged Sunny to continue looking into NP junctions. I also promised him that I would do likewise as it was clear to both of us that we couldn’t proceed any further without some insight here.

 

Sunny’s conceptual journey

Sunny and I had discussed animating the component parts of the NP junction and then explaining each part while it was constructed on the screen. Sunny articulated how he conceived this process in his reflection, saying, “I’m going to build [literally draw each part from scratch by starting with a blank screen] the solar panel as I go through. So I’m going to start with one layer and then do the next one and so on” (Student reflection, 20th October 2011). Of course, Sunny had to create his imagery via this construction process anyway but he was saying that he wanted his finished animation to reflect this process. The pedagogical principle that we discussed was that of starting simple and progressively adding details. The inner workings of the NP junction, however, still alluded us. My reflection at that time was that we needed to go further into the nature of electricity at the component level:

The definitions that he [Sunny] encountered for "N type" and "P type" semiconductors were identical except for certain variables which were switched around. Interestingly, Sunny concluded that each type of panel was interchangeable when, in fact, they are complete opposites. This should be resolved soon when he looks into the structure and composition of the semiconductors (Researcher reflection, 27th October 2011).

A breakthrough finally occurred when I realised that the NP junction needed to be viewed as a whole unit rather than as component parts, an understanding that I worked on via my reflexive journal:

After more reading and research into solar panels, I think I've identified the stumbling block that was halting our progress. This insight is that an NP junction is easier to understand in context. Viewing the N (negative) and P (positive) plates in isolation was confusing as we were breaking the system down too far. The junction effect that creates the voltage is only functioning when the two plates are brought together into a junction. It's almost like trying to understand human reproduction by analysing the properties of sperm and ova without investigating what happens when they combine (Researcher’s reflexive journal, 24th November 2011).

The potential to see this system perspective had been in front of us all along but we didn’t see it because we were too focused on the component parts. This new, integrated view of NP junctions led to a change in the actual topic:

Sunny changed his topic to "Solar cell efficiency" today in response to my suggestion that we narrow the scope to efficiency issues. This allows us to cover important and interesting issues around solar cells without getting stuck at the atomic level (Researcher reflection, 1st December 2011).

Figure 4.5 shows the typically dark colour of solar cells as being optimised to absorb light energy. The voltmeter on the right-hand side implies that electricity is being generated without having to address or explain the direction of the current.

Figure 4.5

Figure 4.5. Screen shot from “Solar cell efficiency” animation.

The most difficult issue to animate was band gap energy. Sunny defined band gap energy as “the strength of the voltage” (“Solar cell efficiency” animation) and noted that its magnitude “depends on how much energy is required for electrons to jump across the NP junction” (ibid). Figure 4.6 is a metaphorical visualisation of an NP junction where the phrase band gap energy was stretched to suggest a literal gap. The positive and negatively charged materials in a typical NP junction create a chemical gap and not a physical one, but the use of distance in this animation reinforced the notion of a gap to be crossed. Andreou (2013) calls this a graphical metaphor when words or symbols are “arranged in meaningful spatial configurations that metaphorically (or allegorically) express relations among the concepts [or] the objects” (p. 15).

Figure 4.6

Figure 4.6. A graphical metaphor of band gap energy as a physical gap.

Sunny also alluded to this graphical metaphor in his director's commentary:

In real life the band gap energy doesn’t mean that the negative and positive sides are further apart (like it looks like in the animation) but that was a good way to show it so that people would understand (“Solar cell efficiency” director’s commentary).

Figure 4.7 extends the graphical metaphor by showing how sunlight can be wasted when the NP junction is not optimised to harness strong light.

Figure 4.7

Figure 4.7. Screen shot of wasted energy in an NP junction.

Sunny concluded his director’s commentary by stating that, “my topic was so complicated that, although it’s still the longest, we had to remove some of the information that we were going to include at the start” (”Solar cell efficiency” director’s commentary). The deleted scene that Sunny referred to would have accompanied the following narration:

Another issue is that the electricity generated by a photovoltaic cell needs to travel through a semiconductor and semiconductors aren‘t great at conducting electricity. Wires are good conductors but they block out light so new transparent conductors are being developed to improve solar cell efficiency.

This scene was deleted to shorten the explanation and keep the duration under two minutes. We were quite serious about including this final point as it seemed that this extra information afforded a more complete explanation. However, we couldn’t think of a clear way to represent this information graphically as the attributes of semi- conductors, although relevant, were complex enough to have constituted a whole new topic.

Sunny realised that solar cells involved changes from one type of energy into another but he was initially mistaken when he identified heat as the original energy source rather than light. “I'm thinking that I need to find out how it changes from one type of energy, heat energy, into electricity that powers things” (Student reflection, 21st July 2011). When Sunny corrected this misunderstanding, he was able to discuss solar cells in terms of the reflective qualities of the outer layer of photovoltaic cells as an issue affecting solar cell efficiency.

After the last animation session, I was left with the task of completing any missing imagery as I had no further opportunities to work with Sunny. Sunny had given me instructions to animate ascending numbers from 0% up to 40% to accompany his voice-over script for, “Even the best solar cells only achieve around 40% efficiency”. After I had generated the number sequence, I decided change the order by starting at 100% and working down to 40%. I felt that 0, 1, 2...39, 40 focussed on how far we’ve come in terms of solar cell technology in contrast to 100, 99, 98...41, 40 which implies that we still have a long way to go. I attribute this subtle refinement to the fact that I had a further opportunity to reflect on the content. When I met with him Sunny during the debriefing session the following week he said that he approved of my choice for this scene.

Table 4.5 is Sunny’s final conceptual consolidation rubric.

 

Table 4.5

Sunny’s final conceptual consolidation rubric

Uses correct terminology With assistance Simplified terminology Some correct terminology Actual terminology

Identifies relevant variables

Not apparent With assistance Basic understanding

Deep understanding

Identifies relationships between variables Not apparent With assistance Basic understanding Deep understanding

Self-assessment scale (1-10). Does the student think that they understand their topic?

1
2
3
4
5
6
7
8.5
9
10

 

A summary of Sunny’s conceptual journey is presented in Table 4.6.

 

Table 4.6

Summary of Sunny’s conceptual journey

Summary table of Sunny's conceptual journey

 

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(1) I found it interesting that in Sunny’s director’s commentary, he described his decision to change topics as “halfway through” the project, however, the shift of topic actually occurred during session 15 which was 87.5% of the way through. Sunny’s concept of time (or at least his concept of time in relation to this project) was also skewed as Sunny thought that the whole Storyboard project ran for one term when it was actually two terms.

 

Proceed to the next Portrait of Neil

 

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