Science Additional Specialism Programme
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Comments Linked to Criteria
Understanding of key ideas:
You show good knowledge and understanding of the key ideas, and have been able to set you work in a wider theoretical context.
In order to improve further you would need to set your work in a much wider theoretical context.
Use of material:
Links between theory and practice have been clearly and effectively made. Your answer demonstrates a good understanding of the most relevant literature.
In order to improve further you would needed to have very well developed critical arguments.
Range and comprehension of sources:
You have demonstrated evidence of an intelligent choice of reading.
In order to improve further you would need to demonstrate initiative in the choice of primary and secondary sources.
Communication:
The structure of the answer is coherent, with a well constructed and clear central argument.
In order to develop further the structure of your argument would need to be organised systematically around a central argument.
Level of citation:
The references and citations are in full and correct form.
General Comments:
An interesting piece of work. More developed critical arguments would have strengthened this assignment further.
First Marker:
Second Marker:
Date: 21 September 2010
Mark: 65
Classification: II(i)
Word count: 8396
Science Additional Specialism Programme (SASP)
Chemistry
2009-2010
Pg 2-9Section A - Reflection and evaluation of the planning and delivery of a sequence of
Post 16 chemistry lessons.
Pg 10-16Section B – Critical reflection of how the learning process undertaken during the
course has impacted on teaching practice.
Appendix:
Pg 17-18Lesson plan
Pg 19Questionnaire analysis
Pg 20-25Lesson activities – starter activity
Pg 26-27 Lesson activities – Electronic structure of the first 36 elements
Pg 28 Lesson activities – Electronic configuration
Pg 29 Lesson activities – Ionisation energies
Pg 30-31 Lesson activities – Ionisation energies – name the element
Pg 32-37 Lesson activities – Practice examination questions for electronic structure
Pg 38-39Lesson activities – Electronic structure homework
Pg 40-41 Lesson activities – Electronic structure test
Pg 42-63 Lesson activities – Electronic structure notes
Pg 64-74 Lesson activities – Ionisation energies notes
Reflection and evaluation of the planning and delivery of a sequence of Post 16 chemistry lessons.
Year group12
Number of students7
Ability of studentsMixed (Grade B - E)
Exam boardAQA
Chemistry topic3.1.1 ‘Atomic structure’
Background
The students I arranged to teach had previously being taught about the basic structure of the atom, about mass number and isotopes and about the mass spectrometer; therefore it was up to me to cover the remainder of the examination syllabus on atomic structure.
Choice of topic
The reason why I chose ‘atomic structure’ with particular reference to ‘electronic configuration’ was because of the fact that I did not feel confident in my knowledge and hence teaching of this topic. I remembered ‘learning’ about the atom while studying for my A-levels 15 years ago, but not really understanding this abstract concept. During one of the sessions on the SASP (Science Additional Specialism Programme) course I began to fully appreciate the abstract concept of atomic structure and felt inspired to go away and read more on the subject matter. Now ‘clued up’, I felt that I needed to ‘try out’ my new found knowledge and understanding on a group of students.There has also been much criticism and many unanswered questions regarding how best to teach atomic structure. (Bent, 1984; Berry, 1986; Gillesphie, 1991; Hawkes, 1992; Shiland, 1995 and Tsaparlis, 1997a, 2002).
Tsaparlis (1997a, p922) sums up the importance of this topic. According to him,
“It is no surprise that the atomic theory has fascinated chemistry teachers and constitutes the cornerstone of modern chemistry curriculums even at the primary school level. As a matter of fact, the study of atomic and molecular structure – from the elementary models to the old quantum theory and later quantum mechanical concepts – is considered a sine qua non in chemical education.”
Lesson sequence
Having observed a series of A-level chemistry lessons in the high school, I decided to follow their successful structure in that I would begin with a starter activity which would recap some of the GCSE syllabus. The main part of the lesson would include an introductory discussion on the topic which would be led by me followed by various tasks which the students could attempt in an order of their choice and complete during their study periods. The plenary would involve a run though of the objectives to check that the success criteria had been met. To confirm that my teaching had been successful I decided that a brief test on the subject would be the starter for the subsequent lesson.
Starter:
As a starter activity I decided to test the student’s prior knowledge of atomic structure from the GCSE syllabus. For this activity, I collated together some questions from the previous year’s examinations. The logic behind this came from the recent reading of some literature. Taber (2003) mentions that the models of the atom used in teaching have consequences for students. Scientists have not agreed on one specific model to use in their work; schools and colleges do not teach with one specific model; and in the minds of learners there is no one model of the atom. The GCSE recommended model of the atom is based upon the Bohr model – it has a nucleus with electron shells. It was because of this background reading that I became aware of the possible mind field that lay ahead of me.I needed to question the students somehow on what they had been taught and what conceptions or misconceptions they had before ploughing ahead with the A-level requirements as learning about the structure of the atom is difficult for many students. Cervellati and Perugin (1981), Taber (2000a,b) and Harrison and Treagust (2000) write about the fact that difficulty is often experienced by students when more sophisticated models of the atom are introduced post-16.
Use of models
Hodgson (1995) mentions that hardly a lesson goes by without the use of one or more analogical models to explain the content. He talks about models providing the means for exploring, describing and explaining scientific and mathematical ideas and declares that they help make science relevant and interesting.
According to Harrison and Treagust (2000) teachers should teach modelling skills and should encourage students to use multiple rather than isolated analogical models, and take the time to discuss and critique the models used in class. They state that highly abstract non-observable phenomena are explained using multiple models and that analogical models stimulates students’ curiosity and imagination and enhances their creative thinking. Grosslight et al., (1991) highlights an important fact that I needed to consider before ploughing ahead and using multiple models to explain electronic configuration. They point out that while the contradictory nature of some multiple models may be understood by the teacher and textbook writer, inexperienced modellers are unlikely to share this view. They mention that teachers should remain aware of the difference between expert modellers (themselves) and naïve modellers (their students). Harrison and Treagust (1996) make the point that atomic theory depends more than any other topic in chemistry on a variety of models to explain particulate behaviour. Justi and Gilbert (2000) have described a sequence of historical models of the atom starting with the ancient Greeks then leading onto Dalton, Thomson, Rutherford, Bohr and finally onto quantum-mechanical. Justi and Gilbert talk about these models having currency at some time in the development of atomic theory and mention that the modern chemical models (i.e. from Dalton on) played a role in research without necessarily being viewed as the ultimate model.
It has been recognised that when teaching abstract and unfamiliar ideas, it is important for the teacher to find some way to ‘anchor’ the new knowledge among existing ideas using metaphor or analogies. Here lay a major stumbling block for myself; while attending the SASP course, on numerous occasions, reference to the ‘Royal Society of Chemistry‘ for resources to be used within school was mentioned. It was here that I originally looked for ideas on how teach electronic configuration and it was here that I came across a resource that asks students to compare the model of the atom with the solar system. Although at first I found it difficult to spot similarities and difference between the atom and the solar system, when reading through the answers, I could see the benefit of such an activity if the students had enough background knowledge. Since the students I would be teaching were not my regular students, I was not fully aware as to what they had previously been taught, therefore this could be an issue to which I would have to consider,
Upon further background reading, I discovered that this activity may not have been as beneficial as I first thought. Fischler and Lichfeldt (1992) argue that initially teaching a model of the atom based on concentric electron orbits may be counter-productive. They found that the planetary orbit preconceptionseems to be especially resistant to change, Taber (2004) mentions how prior teaching about the structure of atoms seems to interfere with new learning. He found that students who are taught a model of the atom where electrons exhibit planetary orbits, in concentric shells, around nuclei, who then go on to study science at college or university level, then, the atomic model learnt at school acts as a ‘pedagogic learning impediment’. He found that when students are told about orbitals, they may interpret the new concept in terms of the familiar shells model. (More about orbital’s later).
Gilbert (1998) suggests that a valid teaching model must be designed to lead towards the current consensus model(s) used in the field. The teaching model should encourage learners thinking towards a more sophisticated level of scientific understanding.
Harrison and Treagust (1996) talk about their being significant problems in teaching and learning with analogical models in school science. They mention that teachers cannot predict how students will interpret the analogical models used by themselves, in textbooks, on videos, or in computer simulations. They point out that while the motivational benefit of models guarantees engagement, it exposes students to private or group interpretations that often lead to unexpected alternative conceptions.
Misconceptions
It has been over 10 years since I have taught A-level, this, and the fact that chemistry is not my specialist subject led me into researching misconceptions that students may have on atomic structure.
To overcome misconceptions is a difficult task. Even when students come close to realising their errors, they revert very easily to their previous ideas with which they are more comfortable. Difficulties and misconceptions in student understanding of atomic structure have been an important issue in the field of science education. Numerous studies have highlighted learning difficulties and misconceptions relating to atomic structure.
Taber (2003) mentions that students often believe that the nucleus of an atom must have equal numbers of protons and neutrons as the neutrons have the role of neutralising the protons. ‘Neutr’ of neutron refers to a kind of neutralisation process rather than a ‘neutral’ charge. The starter activity I had planned would therefore raise this issue and would allow me to correct any such misconception. Taber (2003) also refers to some students believing that orbiting electrons push on the protons in the nucleus to hold the nucleus together. Harrison and Treagust (1996) found that language that is common to both biology and chemistry (e.g. nucleus and shells) was a major source of confusion for some students. For example, some students confused the nucleus of the atom with the nucleus of a cell and believed the nucleus to be the control centre of the atom. The biological influence was also evident when discussing shells, as some students saw shells as acting as a form of protection and, when asked for examples, listed items like sea shells, snail shells, clam shells etc.
Harrison and Treagust (2000) mention that students prefer to think about abstract processes and concepts in concrete terms. Examples of this problem in school chemistry are the depiction of electrons as solid and static instead of diffuse and dynamic. Taber (2002c) mentions that post-16 students can harbour the alternative conceptions of: the nucleus is not attracted by the electrons; the nucleus attracts an electron more than the electron attracts the nucleus; the protons in the nucleus attract one electron each; and the electrons repel the nucleus.
Orbitals?
Post-16 level students are often expected to move beyond ideas about electron shells and to learn something about electronic orbitals. Tsaparlis (1997b) states that serious consideration must be given to alternative ways of teaching chemistry that avoid orbitals. Gillesphie (1996) agrees with Tsaparlis and feels that orbital ideas are unhelpful prior to university level and that ‘electron pair domains’ are simpler and sufficient for school level study. However, examination stipulations may require learners to tackle orbital concepts. As I would be teaching students who would be sitting an AQA examination and the syllabus clearly mentions orbitals, I knew I would have to undertake this concept.
Taber (2002c) affirms that abstract ideas such as orbitals are demanding even for able students, and time, reinforcement and practice are needed if learners are to show (and maintain) a good understanding of the orbital topic. Time, reinforcement and practice; 3 very important words I seriously needed to consider when planning the teaching fro this concept and the learning opportunities for the students.
Taber (2004) refers to research that suggests that students adopt the term ‘orbital’ readily, but often tend to use it to re-label their existing conceptions of electron shells. Students will refer to orbitals as “round” or the “path the electrons takes” as it “circles the nucleus” and diagrams which did represent electrons in shells were said by students to show the orbitals. Taber points out that prior teaching about the structure of atoms seems to interfere with new learning particularly if students had previously been taught a model of the atom based upon the ‘solar system’ with electrons in concentric shells around the nuclei. These students, when told about orbitals, may interpret the new concept in terms of the familiar shells model.
Summary of background reading:
One of skills of a good teacher is in finding ways to make complex ideas seem accessible, but done in a way that is scientifically valid, and provides a suitable platform for further learning. So, I needed to simplify for the students sufficiently, but not oversimplify to undermine their future needs. Taber (2004) declares that over simplifications have the potential to act as significant impediments to further learning. Taber (2003) points out that each teacher will interpret schemes of work and syllabuses in the light of their own scientific subject knowledge, professional pedagogic knowledge, and their personal evaluation of the readiness of students to take on new ideas.
When I first looked at the A-level syllabus it seemed very daunting. It had been many years since I had taught at such an advanced level, and the fact that I was embarking on this in a subject that was not my natural specialism was even more overwhelming,From the SASP course I had gained enough background knowledge and understanding to have the courage to commit myself to further reading on the subject. Once I had the subject knowledge ‘cracked’, I then began researching how to deliver effective lessons to the students. My reading on the subject on the use of models, lead me down the path of using multiple models. When teaching using these models, I needed to ensure that I gave the students plenty of time to discuss and critique the models. Since the students I would be teaching were not my regular students, I needed to consider how they had previously been taught about the structure of the atom. During the starter activity I planned on circulating and discussing with the students what conceptions and misconceptions they currently had on the topic. If the students mentioned the structure of the atom being similar to that of the solar system, then instead of telling them that this analogy is not as beneficial as it first seems, I planned on spending some time looking at the similarities and differences of comparing the atom with the solar system so that the students themselves could then conclude that this is not a good analogy. (I did hope though, that this analogy was not raised by the students).
Misconceptions was another major hurdle to begin with, but with the background reading, I felt confident knowing what the common misconceptions students may have on the subject. I do believe that once you know the likely misconceptions that students bring with them to the lesson, you (the teacher) will be able to, via discussion; diagrams etc. show the students the correct scientific concept