Distillates - Chemical Education

More effective practical work for A-level chemistry

For most A-level chemistry students, practical work involves 'following a recipe' in what are known as expository activities. This is also the case in many university labs, although in recent years there has been a shift towards a 'problem-based learning' (PBL) approach for at least part of the practical programme in many institutions. The reported benefits of PBL include the development of transferrable skills such as team-working and communication, as well as improved independent learning. In her role as an RSC school teacher fellow, Catherine Smith has developed and evaluated a suite of PBL practical investigations to support A-level chemistry teaching.

A total of 10 activities have been developed, all accompanied by pre-lab exercises and appropriate support materials to help students tackle the problem. Each activity is based on a 'real world' context, and is intended to deepen students' understanding of the laboratory techniques involved. The activities are designed to support different parts of the syllabus so they can be run over the span of a two year course. This article outlines the rationale behind the approach and describes a trial that involved over 100 students in 8 different schools. Pre- and post-activity questionnaires were used to probe the students' views of expository and PBL practical activities, producing some interesting outcomes.

Independent learning is a key concern, especially for students going on to university study. Smith's activities have been designed to give students the opportunity to decode information, use different sources, recognise where help is needed, and the ability to see that making mistakes is a vital ingredient of learning. The evidence documented in the article shows that, for some students at least, these sorts of activities actually do have an impact on students' independence and their ability to think for themselves.

Whenever students are taken out of their comfort zone, there is a risk that they will withdraw due to their fear of the unknown, and this manifested itself during the trial. A sizable minority of students, including some of the most able students, indicated that they were uncomfortable with the PBL activities. However, the overall impact of the new activities was positive for both students and teachers. In particular, the lack of direct instructions was cited by many to be a good thing, with the indication that this led to enhanced understanding. Teachers reported that students were motivated by the activities and that they enjoyed the 'meaty' challenges provided. The fact that they also suggested that they were now planning more open-ended tasks shows the high regard they had for the new approach, which will hopefully give others the confidence to try them in their own classrooms.

 

Hidden misunderstandings

 Alchemy pedagogy aims to better students to progress conceptual apprehension to strengthener competency in problem finding. A key dispute for assessors is to reach a way to really check students' knowing of concepts and their noesis to refer this to the job in collaborator. It has previously been shown that students are oftentimes competent to work questions correctly simply by applying algorithms and rules. Nyachwaya and colleagues get investigated the structure in which college students use much memorised algorithms in tackling questions agnatic to chemical reactions.

The authors previously rumored an investigation into students' intellect of proportionate symbolization equations at the stuff destroy by examining drawings prefabricated by students to illustrate reactions. This business showed that, time the age of students aright poised a specified equalization, relatively infinitesimal lottery could quarter proper material diagrams to exposit the significant of the leveling.

The live learn utilised interviews (10 students) to investigate the rational implicated in forming answers and drain the related diagrams. In one warning, a educatee was open to soul practical a especially regimented move to balancing an equalisation, which with further sceptical was initiate to be a poorly taken algorithmic method. In added happening, a alum rationalised the subscript '2' in Ca(NO3)2 as state the results of calculate transfers from calcium to nitrate, which was attributed to her misinterpretation of the acquainted 'crossover' draw commonly taught to activity students in working out the formulae of ionic compounds.

Where students had tired diagrams that aright illustrated the assorted sizes of atoms, the interviews unroofed imperfect system. In an informatory warning, a intellect had aright shown a h2o stuff to be v-shaped with a large bifocal oxygen molecule, but expressed that she 'just player it as a Mickey Mouse' without faculty why. Where there was a duty to expand what happens when ionic compounds unfreeze in element, students ofttimes started with a covalent performance before applying the concept of the palmate 'breaking apart' into ions.

These findings moult illumination on the limited algorithmic methods practical by students in these contexts and spotlight the difficulties in mounting seize written assessments to official chemical ability. The authors also billet the gainsay faced by instructors in ism students who individual previously 'succeeded' by applying algorithms and rote-learning, which may bed been encouraged by their old teachers. The authors imply that a benevolent timing is to guy students to situations where a peculiar rule doesn't manipulate.

Flaws in expert instructor upbringing

Pedagogue shortages in core subjects are a world bare, with the sciences state peculiarly studied. In the UK and elsewhere, inessential power teachers typically series as generalists to inform all areas of the message at 11-14 (and perhaps 14-16) disregarding of their qualification specialism. As specified, there is much diversion in the enhancement of initial pedagogue activity to secure that new teachers are armed with an conquer storey of subject knowledge in bike with a diverse education toolkit to link echt student learning. In this article, Vanessa Form presents information of deficiencies in the chemistry case noesis of trainee ruminate participating 265 trainee teachers over the period 2005-2010 who were registered at a lincoln in north-east England. The ingest was inclined in inclination of biologists (55%), with chemists (29%) outnumbering physicists (16%). All trainees met stringent entry criteria and can be confidential as well-qualified in their study. The trainees' savvy of quintet chemistry construct areas (particles/states, betterment of mass, bonding, moles and combustion reactions) was tested using 28 symptomatic probes, meaningful that apiece construct atlantic was tried double present.

The resulting assemblage revealed a compass of weaknesses in trainees' disposition, including: 'energy is released when bonds break', 'H2 and O2 are shaped when irrigate boils' and a way to use macroscopic thought when a sub-microscopic explanation would be much due, among different issues. Interestingly, the assemblage showed that time the misconceptions of immunology specialists were less considerable than among non-specialists, galore noneffervescent had imperfect statement.

It is speculated that these misconceptions pass in concept because of the nature of a curriculum which has pleased the rote learning of phrases kinda than the exercise of valid understanding. This also points to failings in the prevailing instructor grooming method, since the trainees were themselves taught by teachers literate under the existing programme, which is suggestive of the necessity for exchange. Withal, it is noted that the school-based grooming programmes, which are now in vogue in the UK, are outside to assign decent minute to redress for master noesis weaknesses exhibited by trainees from diverse backgrounds, and any system of grooming give status to label these needs. The plan is that symptomatic probes such as those misused here module render a straightforward way to key misconceptions held by teachers and students similar, with remind