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Having spent six weeks in the new school, and trying out microscale practicals with a variety of different year groups, I thought it was time to put some words down on my experiences so far. I have written previously about this in Education in Chemistry with a more theoretical and personal historical perspective, so this post is more on the actuality of introducing a new style (or just new) practicals to a school and my classroom. I had made some use of microscale in previous teaching jobs, and spent a lot of time at OCR thinking and writing about it. I am now keen to give microscale a good go at the new school for several reasons.
Firstly, I think the more limited equipment and small required field of observation can reduce the extraneous cognitive load on the students, giving them more free working memory to allow for interpretion of observations at the time they are making them.
Secondly, my current school has 45 minute lessons, and I get very few double lessons over the fortnight timetable. Having taught nine years of hour-long lessons, I’m still adjusting to this significant reduction in the teaching period. More organisation is needed by me on the preparation the students do before the practical session, e.g. having them read practical sheets / watch videos of the techniques etc.
Thirdly, I have advocated microscale strongly while at OCR, so am very keen to see the benefits across a wide number of groups. While I’m not teaching to either the Gateway or 21st Century specifications, I’m making use of these practicals never-the-less. I think one of the major advantages of the new specifications is the freedom teachers have in choosing which practicals they use throughout the course, so I’m grasping the opportunity with both hands!
Lastly, it fulfils a personal interest in maintaining a toe in the waters of research. I presented some intentions at MICER17, and now that I’m back in school I can do something about investigating the effectiveness or otherwise of microscale, rather than just theorising about it.
So far, I’ve tried out five microscale practical:
1. Chromatography of leaf chloroplasts. I did this with two Year 9 groups, a higher ability and a lower ability group. The chromatograms ran relatively successfully, but the main problem was the size of the spots – most students made these far too large, so any distinction between the components in the mixture was lost. I found extraction of the chloroplasts from the leaves took much longer than I’d predicted, so I suggested to a colleague who also tried it out, to do the extraction prior to the lesson and then have the students just spot and then run the chromatograms – this led to a more efficient practical session in his class.
2. Microscale synthesis of copper sulfate – this was partially successful – half the group managed to follow the written instructions without additional help and got to the copper sulfate solution quickly and efficiently. The other half (same group as the titration – below), seemed very hesitant to read instructions carefully, or more than once, and were persistent in asking me what to do next. We did a larger scale version as well as a context for crystallising solutions over a waterbath and filtration with fluted filter papers, and got some lovely crystals.
3. Electrolysis of copper sulfate to aid consolidation of the discussion of industrial copper production. I replaced the CuCl2 with CuSO4, so we didn’t have to deal with chlorine production, and as such the potassium halide and litmus paper weren’t necessary. The majority of the students set up the electrolysis apparatus quickly and got to relevant observations within about 5 minutes of the ‘go’. I was also using this as a test practical to see how practically competent the Year 11 group were (having just taken them over), and how well trained they were in cooperative working. Some of the students were spontaneously talking about redox when observing the copper and oxygen production, and this led to a fuller discussion of electrolysis than I’d planned.
4. Metal displacement reactions to consolidate work on the reactivity series, with Year 8 students. I didn’t give the students the written instructions for this activity, rather demonstrated the setup with an IPEVO Point to View camera (a great investment I think for any teacher). I used the drop-setup sheet in a plastic wallet and the majority of the students managed to set up accurately after the projected on-screen demonstration. There were some who managed to get the drops wrong the first time, despite the printed chemical formulae on the sheets, but the small scale made clearing the sheet quick and easy, and they didn’t lose too much time. Most made good observations, and some managed to articulate the link with the reactivity series immediately, pointing to the live observations as evidence when questioned.
5. Gravimetric titration – I used the ‘The Vinegar Dilemma’ as a consolidation activity for my Year 10 Combined Science group. While they aren’t required to know titration theory, the practical links directly with the required understanding of concentration. They had also had a string of rather dry calculations lessons previously, and they and I needed some hands-on learning. There was a distinct split in this group. We read through the instructions together, I demonstrated the setup and then ran the first titration with them observing (12 in the group). Half of the group then got on with no further requests for help and gained fairly accurate results. The other half, were persistently asking ‘what do I do now?’, ‘what’s next?’, even while holding the instruction sheet in their hands. This group is still relatively new to me, so we’re still building the class relationship, and I’m working hard to instil some more self-confidence in their abilities. I think this latter half were slowly getting the message the all the necessary instructions were to be found on the printed sheet, but were frustrated with what they perceived as me ‘not helping them’. I’ve taught groups like this in the past, and I’m sure they’ll self-reliance will improve with time.
I think the most significant thing I’ve confirmed for myself so far is the importance of trialling new resources before widespread use in the classroom. There are already adaptations I’ll be making to some of these practicals before using them again. Lots of resources are produced from many individuals and organisations, but live testing of them with students must be critical to their development and long-term success.
So what next? Well, I’ve ordered myself some dropper bottles to make up the boxes for ion tests as a start. We’ve got a set of the small glass vials which have been useful. I’ve got plenty of other practicals I’d like to try out, but I’m feeling a little swamped by the process of starting in a new school, establishing a reputation with colleagues and the students, and taking on adult volunteering in the school’s CCF RAF section.
I intend to be more systematic in my evaluation of the microscale practicals I use before I start rolling them out across the department. I’d be interested to hear how other people have done this in their departments, and the barriers they faced in up-take by other members of their departments.