M. J. Hudson Unlverslty of Readmg Whitekn~ghts.Readmg RG6 2AD
Some Recent Innovations in the Teaching of Chemistry in the United Kingdom
There have been many innovations in the teaching of chemistry at all levels in the ilnited Kingdom. The purpose of this article is togive an overview of someof these developmentsnnd to look at a few ideas in moredetail. It is huperl that there will he future articles which will deal with other developments in this rapidly changing subject to develop clnse links between the tountries. In these articles terms such as orimarv. .. secondary, and tertiary, which are related to th; United Kingdom svstem. will be used and these will be ex~lainedas thefare used. Very little chemistry is taught a t tl;e primary level in which pupils are from five to eleven. There are schemes, however, which have attempted to introduce science at this level (1, 2). Of particular interest with respect to Science 5-13 curriculum schemes is the method used for the evaluation of the course itself and of the progress of the pupils. The evaluation assumes the Piagetian model for conceptual development and then seeks to relate the stages of development to changes in attitudes, the abilities to observe; to develop logical thinking, to devise experiments, to acquire knowledee. to communicate. and to interoret findings critically. As ieachers of chemist& at secondar; and tertiary levels we should find that many of our students are developing these skills, for whenever a student reaches a new problem they revert to concrete (level 2) methods of thinkine. The ahilitv to communicate has been chosen (Table 1) aH a exam~le Chemistry In Secondary Schools Chemistry teaching is changing rapidly in secondary schools. which are for ouoils between the ages of 11and 19. There are many reasons fir the rapid rate oiihange which are all interconnected. Brieflv. one might mention that the raising of the school leaving age, iack of finance, the introduction of com~rehensiveschools, intearated sciences, core curricula withuptionsand pressureson~hetimetahle have all had their effevts (m chan~ingthe amount i f rhemistrs that has been there has been a great dealof research into taught. objectives, concepts, attitudes, practical work, project work, education techniques, assessment, and research methodology has changed. However, in this article a few juicy tidbits have been selected in order to whet your appetites for more information which can be supplied in future articles, if you want them!
oreo over,
Table 1. Part GI the Evaluation Scheme for Science 5-33 Ability to tabulate information and use tables. Stage 2A Stage 2B
Ability to interpret observations in terms of trends and rates of change. Ability to use histograms and other simple graphical forms for communicating data. Ability to construct models as means of recording ~hse~liions~
Stage 3A
Ability to select the graphical foim most
appropriate to the information being recorded. Ability to use three-dimensional models or graphs for recording results. Ability to deduce information from graphs: from gradient, area, intercept. Abilities to use analogies to explain scientificideas and theories.
Stage 2A refers to me early stage of concrete operations. stsge 3A referr to me esrly stage of formal operations
Undoubtedly, the most important iingle curriculum change has heen the Revision of Nuffield "0" I.evel (:hemistrv. The original project was started as an avant garde development oroiect in 1962 and had a tremendous influence on the LaEhing of chemistry hut has now been revised completely. I t is hoped that the few teaching ideas outlined here will he of interest to readers. The course is outlined in Figure 1.Pupils of the ages 11-13 often take a science, rather than a chemistry course, but they may opt to do chemistry at the age of 13 or 14. The "0"level examination is taken a t 16+ after which the pupils may elect to study "A" level chemistry. The Revision was originally spearheaded by Dr. R. B. Ingle and as a result of a questionnaire i t became clear that the teachers were very unhappy about the topic on gram-atoms. They felt that this topic (now called the mole concept) was too early in the original scheme and not only should it be placed further back but a t the same time a method was needed to reduce the mathematical and conceptual difficulties of the tobic. For this. and other reasons, there are now two routes th;ough the second stageof'.O" level n~arerial.'l'heStage 11A is cssentiallv an updating of the originnl acheme, but Stage IIR
Volume 57. Number 10, October 1980 1 715
Figure 3. Some possible formulas for lead bromide
A. 24 mg of magnesium atoms comhine with 16 mg of oxygen atoms B. 24 g of magnesium atoms comhine with 16 g of oxygen atoms. C. 1 mole of maenesium atoms comhines with one mole of oxygen atoms. D. The formula of maenesium oxide is MeO. The mathematical difgculties are reduced to a minimum because the jump from A to B is about the most demanding mathematics that is required. The steps from B to C and from C to D do. of course. need to be verv carefullv introduced hut the progressive steps from atoms, arrangement of atoms, masses of atoms, counting atoms and combining atoms do seem to alleviate much of the difficulties which pupils have. The above approach encourapes them to use the mole rather than understand the concept-It is hoped that understanding will follow this utilization. The scheme can, however, he developed to study the combination of the elements such as copper and oxygen, or lead and hromine, or sodium and oxyZen. The formulaof lead hromide. fdr exam~le.is interestinz establish after MgO because i t shows a i:2'formnla. he lead in the hromide is disblaced hv aluminium and the excess aluminium
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Mass o f o n ~ p m l p Figure 2. Sample results for the determination of oxide.
the formula for magnesium
represents a signiiicant difference which was t)n~uyhralmut hv the opinions expressed in the questionnaireand theore~ical dr\,rlopments in the tench~ngof chemistry. Fortunatrly, t h c e uns an agreement betueen the theoretical ("Piagetian", madel nud theminions e~oresserlhv the teochers who redied to the questionnaire. Essentiallv the chanees which have been introduced hv the revision ceiter aroucd the idea that the more difficult chemistrv has been left till later in the course. Since the Piagerian model for concept~~al devehpment was largely assumed, the critt.r~aofdiff~culfvwas huoed on this model r ? l . In terms this has meant that topics (see Table 2) dealinn with atoms, or the arrangement of atoms (structure), saJids, liquids, and gases and numhers oi particlei haw Oeen put much later. These lopics lay the foundation ior, and give an introduction to, the whole mole concept which has essentially been moved hack tojust before work on electrolytes and dvnamic eauilibria. On the other hand. the t o ~ i c which s deal with hydrogen chloride ("salt gas"), acids, how.fast? rates and catalysis, The World Food Problem and Large Molecules have been brought into the scheme earlier. The mole concept still remains one of the most difficult conceDts in the school chemistry course, but oneoithe ways in which the nmceptual level of diificults may t w reduced is to introduce a ara~hicul approach ( 5 , 6 ) .In this, pupils experimentally determine how much of one element, e.g. magnesium, comhines with another, e.g. oxygen. The results of these experiments are plotted on a graph and, with luck, or judicial selection of points the results fall on a straight line (Fig. 2) and taken through the sequence of ideas namely: 716 / Journal of ChemicalEducation
3PbBrz + 2A1- 2AIBn + 3Ph is dissolved in alkali. T o do this experiment a weighed amount of lead hromide (=lg) is heated in distilled water (50 cm?. Aluminum powder is added carefullv to the hot solution. Sometimes frothing is a problem, hui a small amount of a silicone may he added to stop this from happening. Once the aluminum has been added, the boiling is continued for another 15 min and sodium hydroxide (40 cm3) is added. The lead needs to he broken u p ~ afirst t to allow the sodium hydroxide to extract the aluminum and then should he recompressed. Thk water is decanted off and the lead washed with acetone and weighed. The mass of hromine (Fig. 3) is obtained by the difference between the mass of lead hromide and that of lead. At Advanced level, which is for pupils of the age range 16-18, there have been many changes hut we are not sure yet whether there will he any revision of the Nuffield "A" level Chemistry Teaching materials. The Joint Matriculation Board has, however, introduced an ambitious syllabus in which t,here is a bias toward a knowledge of industrial processes. In addition, there are core-studies (7) including: (a) The Problem of Effluent Disposal (b) , , The Use and Ahwe of Drwr (c) Five Routes to Phenol (d) Sulfur and the Environment ~
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Table 2. A Brlet Comparlron Between the Orlglnal Nuflleld "0" Level Chemlstrv Scheme (A) and the Revised Scheme (8).
Topic Title Aims Hydrogen Chlwide Periodic Table Arrangemems of atoms Solids, liquids, gases Electrolyies NOS.of Particles HOWfast? Dynamic Equilibirum AC~S Large Molecules World Food Problem Chemicals end Energy Radiochemistry
Topic Numbw A B Scheme Scheme
11 12 13 14 15 16 17 18 19 20 21 22 23 24
Ie(18) 11 16(24) 17 23(17) 19 20 13 20(21) 12(20) 15 14 23 22
Comments Much later Much later
Much earlier Much earlier Much earlier Much earllw Same
(e) The Spray-SteelProcess (0 The Salt-Based Industries Of these, my own favorite is The Salt-based Industries (0, hecause a great deal of fundamental descriptive chemistry has heen developed. The pupil is presented with a discussion of the industrial uses of salt, the origins of the natural deposits of salt. the need for alkali. the historv of Leblanc Process. the use and importance of hydrochloric acid and hydrogen chloride. the Solvav Process. elcctrolvric Droresses. the location of salt-based- industries and >he- chloralkali balance. Throuehout there are questions and answers which are designed& promote the students interest in, and understanding of, the subject. Assessment techniques have received a great deal of interest for this and all other courses. The general impression seems to be that "if you cannot assess it you should not teach it!" Much attention has, for example, been paid to objective, short answer questions which werp designed to allow the less articulate pupil a chance to benefit from an examination in which a fuli written answer was not required. However, the words which cause trouble are the normal English words which have a snecial meanine in science. The word volume has manv meanings such as the L o b on the radio; or even, the loudness of the radio or T.V.; but rarely, the amount of gas or liquid. The findings of the Chemical Society's investigation into laneuaee have been published (8).and it is quite clear that the language level is too high for the less articdate. Masters degrees in Chemical Education have now been established a t the Universities of East Anglia, Reading, Southampton, and York and active research schools are developing in Glasgow, Reading, and East Anglia. Reading and East Anglia have each had over one hundred teachers of chemistry through their Masters degree programs and teachers from these and other courses have made significant contributions to the development of chemical education as academic disciplines. Many universities offer higher degrees
in science education. some of these courses have sienificant amounts of chemicaleducation, and chairs have been established a t Cardiff, Chelsea, Keele, and Leeds. I t is difficult to choose one example of the way in which teachers taking Masters courses have contributed to chemical education in the United Kingdom because many teachers have made important contributions. The popular Option on Water (9) which was devised for the Nuffield "0"level course arose directly out of a masters degree dissertation submitted hv a teacher on s~condment.The options are mentioned in Figure I and in the original Scheme (A) they were largely used at the end of the course, but in the new Scheme (B) they may be inserted into several points. This option on "Water" and indeed the whole of the Teachers Guide (9) one of the . . renresents . major landmarks in the development of chemical education in the United Kingdom. The whole hook is clear. conrise. imaginative, and Gautifully illustrated. An outline of the contents of a single course clearlv cannot do the o ~ t i o niustice. but, at least it wiil offer an impression of what theiuthois were trying to achieve. Section 1.What is water? Section 2. Where does water come from? Sertron 3. H o w do we use water in the home? Section 4. How i i water used in indurtry and agriculture'! Section 5. \I'hat happens w water after we have finished w i t h it? Section 6. How canwater he analyzed? Section 7. Where can we find water in the future? The language level of the option is carefully chosen. Each pupil should have his own book. Teachers are given a clear idea of how much time to spend on each section and the experiments are clearly summarized as they are in all of the Teachers Guides. One of the main appeals of this type of option is that it relates chemistryto the everyday needs of society which chemical educators are reauired to do. Clearly there are many challenges ahead for chemical education in the United Kingdom (IO),but one can say that schools, colleges, polytechnics, and universities are working reasonably well together to improve chemical education. If this article has promoted your own personal interest in the chemical education in the United Kingdom, please write to the author giving information as t o what yo; would like to know about. Literature Cited (1) Nullield Junior Seienrr. Longman. 1969. (2) Schools Council Seienee 6/13 Project. Available from Science 5/13, Tyndsll Avenue,
Bristol BSQ ITQ.
Volume 57, Number 10, October 1980 / 717
