Student lessons

Weak Acids and Bases. The term weak suggests in itself the following most common misconception weak acids are weakly concentrated . It may well be that during students lessons, protolysis equilibrium of acetic acid was used as an example, maybe perhaps even equilibrium constants came into play, and pH values of specific acetic acid solutions were measured or calculated -however, only a few students are able to comprehend and connect all these facts to develop the scientific idea about weak acids. 

If fondly recall the first day of an introductory graduate statistical mechanics class. As our instructor walked into the class saying something entirely appropriate like So, are we all ready for a lesson in quantum field theory today , he was of course met with a room-full of blank stares (even a few - later embarrassed - behind-the-back giggles). As first-year graduate students we had unfortunately not yet developed the requisite maturity to appreciate the profound link that exists between statistical mechanics and modern field theory. I resolved to never again be as quick to dismiss any obvious disparity or seeming disconnectedness between two subjects. 

Of course, nowadays, as every student of chemistry and physics knows, electron orbits have been replaced by orbitals that are supposed to be smeared out in space. But this view misses the point somewhat and is not the whole lesson from quantum mechanics. The more radical lesson is that even these probability-based orbitals simply do not exist. The notion of assigning four quantum numbers to each electron is just an approximation, albeit a powerful one. 

Using Environmental Examples to Teach About Acids. Acid-base reactions are usually presented to secondary students as examples of aqueous equilibrium (2). In their study of acids and bases, students are expected to master the characteristic properties and reactions. They are taught to test the acidity of solutions, identify familiar acids and label them as strong or weak. The ionic dissociation of water, the pH scale and some common reactions of acids are also included in high school chemistry. All of these topics may be illustrated with examples related to acid deposition (5). A lesson plan is presented in Table I. 

The separate parts in the school chemistry textbooks are accompanied by student-exercises that mainly aim to train the students ability to reproduce the chemical knowledge presented. It takes quite a large number of chemistry lessons before a student will come to a point where the new chemical knowledge may be related to society and the everyday world. Only some students start to ask about nitrates and environmental problems while climbing the ladder. Mary never make such a coimection. According to the common ciuriculum philosophy that students first need to climb the ladder , it takes a long climb for students to see the relevance to societal themes in fact it is impossible within the (time) limits of the school chemistry curriculum. 

Students go on to investigate rates of corrodibility and the reactivity series is introduced. Methods to prevent rusting are considered in a homework exercise and further opportunities to study the methods of rust prevention are provided in two optional lessons. 

When a technical language is adopted by those who do not share the expertise of its parent community, it may actually become distorted, and this may make it even more difficult for students to keep clear what different forms of symbolism mean. So in biology lessons students are likely to meet equations representing photosynthesis and aerobic respiration (Examples 7 and 8 in Table 4.1). When just considering the substances involved, these two equations will seem to stand in the same relation as those discussed for the hydrogen/nitrogen-ammonia equilibrium ... 

Of particular relevance to the above discussion is the way in which learners initially handle incoming iuformation such as that presented in a lesson, a lecture demonstration or during laboratory instruction. The new irrformation is perceived and filtered in terms of what the learner already knows and canimderstand. As a result, iuformation is not transferred intact from the mind of the teacher to the mind of the learner. It undergoes an initial selection (filtration) process and what is admitted will vary from person to person. Students with a similar backgrottrrd will tend to select in a similar, but not identical, way (Johnstone, 2007). An information-processing model is presented in Fig. 5.1. 

Finally, the diagnostic instrument may be administered before commencing a particular topic in order to gauge students prior rmderstanding of the associated concepts. At the same time, the use of the instrument as a formative assessment tool will enable the teacher to take appropriate measttres to challenge ary students conceptions that may become evident dttring the lesson or plan for remediation with small groups of students that experience difficulties. 

Data were gathered during activities described in the six lessons of 100 minutes. In Activities 1-5 (in consecutive lessons) stndents worked in gronps (4-6 students), while in Activity 6 (some weeks later) stndents worked individnally. This teaching approach was adopted to promote stndents nnderstanding of how a chemical equilibrium process occurs by supporting the nse of empirical observation and... 

Data were gathered from written material produced by the students during the whole process (including the final questionnaire, the video recording of all lessons, and audio recording of the discussions of each group of students). 

Data gathered in the lessons were used to produce case studies for each of the groups of students because such case studies yield rich descriptions of events that are presented in a chronological narrative that incorporates the researcher s observations. Due to the possible inclusion of such an interpretation of the data, case studies go beyond simple descriptions of the situation and support the analysis of the phenomenon being studied (Cohen, Manion, Morrison, 2000). In order to discuss the research questions, we browsed the original case studies to identify evidence of how the students dealt with the levels of representation. Whenever it is appropriate, such evidence is included in the later sections of this chapter. 

The way that the teacher conducted the lessons contributed to making some details of the systems explicit and helped students in interpreting (i) the empirical evidence, (ii) the questions to be answered by the models, and (iii) the symbolic representations she presented for each system. Moreover, the teacher s questions supported the students as they tried to remember previous ideas and/or models, to identify the limitations of their models, to propose new models or new explanations for the use of their models in new contexts. Finally, the teachers questions were very helpful for increasing students confidence in their models. 

The capacity to translate between the levels The role of the symbolic level in the production of explanations changed as the sequence of activities was followed, becoming suitably dominant in the later lessons. At the same time, mental switching between the macro and sub-micro levels became ever more fluent. Moreover, during the process, students progressively increase their capacity to decide which level would be more adequate in a given situation. 

From the contents of the teachers reflective diaries, the following differences in the lessons provided could be observed (1) Some teachers added extra exercises in knowledge consohdation, (2) some teachers left out particular activities, (3) some teachers adjusted the duration of particular sections (Fig. 13.2), (4) teachers used different motivational approaches to facilitate learning, e.g. students were rewarded with marks for their success in the Test of Gained Knowledge at the School N° 4. The duration of particular parts of the teaching plan is given in Fig. 13.2. 

The teachers reflective diaries were confidential to themselves. However, they were all requested to report about their experiences in outline from the reflective diaries, as follows (1) detailed description of each lesson, (2) differences in classroom practice for each of the conducted lessons with regard to previous year(s), (3) their estimation of the results of each of the lessons in the sense of students motivation and knowledge, (4) suggestions for changes/improvements for each of the conducted lessons and (5) their general ideas for the improvement of the teaching unit and the LON approach. 

The homework assignments related to everyday life provided excellent students feedback. Despite not being foreseen in the LON teaching plan, due to great student interest, we prepared an exhibition of different home-made models for the coal-burning reaction. Most students were very inventive in the selection of materials for home made models to represent chemical reaction at the particle level. [Teacher from School N° 3, additional lesson after Section 2]... 

After students eondueted the experiments, I didn t observe problems in their writing down of ehemieal equations neither in the word nor in the symbolic form. 1 believe this is due to the use of models in learning of writing down ehemieal equations in previous lessons. [Teaeherfrom Sehool N° 1, Seetion3]... 

This lab reaffirmed my desire to be involved in medicine and not research. Lessons abound from undertaking original research success, failure, trial and error. These lessons are simply indispensable and should be rated among the top experiences a student can undergo. ... 

Adiramled. The art of alchemy or the generation of gold a course of practical lessons in metallic transmutation for the use of occult students being a new illumination regarding the secret science of the sages. Lightning Source. ISBN 0766175774... 

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