Teaching and Learning the Salters' Way J. N. Lazonby Department of Educational Studies, University of York, York YO1 5 0 0 , UK
P. E. Nicolson and D. J. Wadddington Department of Chemistry, University of York, York YO1 5DD, UK Too often teachers c o m ~ l a i nabout school science courses: Many concepts appkar to the student to be both difficult and irrelevant. Science education in the United Kingdom has not escaped these strictures. From the mid1980's, three national curriculum-development projects based a t the University of York have been working to address these twin problems. The projects have two things in common: the name Salters, which is a charitable organization that has partly funded the work (1);and the method used to develop the materials. Teams of universitv and school teachers. science educators, and industrialisk have worked with two national examination hoards. Some 100.000 students have studied. or are studying, for national examinations using the materials pmduced by the projects (2). I n this paper, we will describe and discuss the first two projects. The Chemistry Project, for 13-16 year olds .The Science Project, for 11-16 year olds A future paper will deal with The Advanced Chemistry Course, for 17-18 year olds ( 3 , 4 ) . Designing the Curriculum The challenge to all curriculum developers is to provide a curriculum that captures interest whiie catering to the educational needs of students.
each course. The following pairs of concepts and contexts are examples. Link the rates of reactions to food decay and to acid rain on buildings (5). Link catalysisto the role that enzymes play in fighting disease Ifii \-,. Link particle theory to phenomena seen in a wide variety of drinks (8).
Link photosynthesis to a series of fictional experimental reports generated by a confused, hut curious, visitor from a distant planet. (He is intrigued to find such an amazing process going an in the "Green Machine" that stands unattended on so many parts of our globe! (91.1 Encourage Active Learning and Exploration Amore detailed example is given later in this paper. This approach has been graphically described as curriculum development through the looking glass (10).The work must involve students in a wide range of activities in which they are encouraged to learn, rather than simply being taught. Interactive Study The course could he given by the teacher in a series of lectures and demonstrations, but this is not the Salters' way. We use a variety of learning strategies and encourage participation in many types of actitvites.
Learning Strategies
The Goals I n science curricula, a t this level, various goals must be remembered. To address the needs of students who wish to pursue the sub-
ject at a higher level. To inspire students to think about science and technology in terms of their future careers. To educate all the others, the large majority, to enable them to work and live enjoyably and effectively in a society increasingly dominated by science and technology. The Criteria Many curricula are devised by defining what is expected of students a t the end of the course. We deliberately closed our minds to this and considered the followine t h e e criteria.
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Relate the Course Material to Life Experience Consider what students might bring to the course a t that age, and base the content of the course on something from their lives that they have experienced either first-hand or through the media. Link Concepts to Context Introduce the underlying science concepts only when they are needed to help the student understand the work. Thus, the concepts are linked to a context that students perceive as important as presented in a series of units for
The students are kept involved throughout the wurse using a wide range of cooperative learning strategies. student practical work small group discussions creative writing and reporting 'role-playingexercises for discussingvalue-related issues exploration of various other decision-makingactivities Activities In all this, we were influenced by recent research, in particular constructivist theories and the role of student talk in learning (9).These led us to look for opportunities for student-student discussions in contexts that require the student to participate in a broad variety of activities. We want to encourage students to get involved. To articulate their understanding of the concepts To plan investigations To discuss implications of data To consider social and economic issues Some of the discussions lead to presentations that are meant to be delivered by the students to the whole class, either orally or with The discussions may alsolead to some creative writing. The teachers' role is to provide a varietv of o~oortunitiesforstudents to learn abo& the science a"s muLh as to teach students directly. Volume 69 Number 11 November 1992
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Course Materials All the criteria used sound fme, but can they be made to work? The Salten' courses have already been described a s challenging, and indeed they are, for both teachers and students. To adopt such a n approach, teachers rightly feel that they must be well-supported. The content is set in new contexts, and students are being invited to participate in different learning strategies. We wanted to provide enough guidance to make these strategies clear.
Making Use of Oil Overall Plan
tlon polymer, polystyrene. usng car-wdy f ler paste Thev learn awJt tne Iformation of condensation polymers and devise models
need to transport oil and the ways in which an oil spillage at sea might be cleaned up.
Curricular Design Criteria The design criteria for the materials evolved after a ereat deal of discnssion with teachers. The most imwrtant :riteria were that the published materials should~accomplish the following. 'Give teachers a quick overview of the units within the course. 'Provide detailed guidance and support for inexperienced teachers. 'Present a structure that encourages the more experienced teachers to begin the process of continual review, renewal, and development of the murse. Using Unit Guides The teaching material is organized as unit guides, one for each topic, for the teacher's use. Each begins with an overview of the unit and a n overall lesson-by-lesson plan (Fig. 1).These satisfy the first criterion. An outline is given for each lesson in the unit (Fig. 21, which identifies the activities, outcomes, and skills usedand thus satisfies the second criterion. More extensive of the notes follow each lesson to mide the manaeement lesson, and to suggest questions for prompting discussion. Uncopyrighted masters for student activity guides and information sheets are also included. The third criterion is met bv producim the unit mides in of lesso& can he loose-leaf form so that lwno~s'and modified and replaced by teachers. The unit guides provide the basis from khich schools develop theirown teaching schemes. I t is not possible to provide for the needs of all students with a siigle set of worksheets, so advice is given for adapting these activities for a variety of skill levels.
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Text Chapters to Support the Guides Unit guides have been produced in very simple form, cntting the cost wherever possible. Student texts have been published commercially to support the unit guides (11-13). We believe that they have a unique and very helpful structure that complements the guides. First we analyzed how a book is used by teachers and students, and then we wrote the text. Each chapter is based on one unit, and i t contains five parts. Introducing, a single page, sets the scene, telling the student what the chapter covers and why the topic is important. Lookine at is a collection of three or four text-related activi-
t1e;attractively illustrated by color diagrams and photographs. They show important applications and uses of the scientific ideas to stimulate interest. In brief is a summary of what the student needs to know and understand about the topic-a quick reference. Thinkingabont explains the scientific ideas developed in the unit. Things to do is a collection of suggested activities. activities to trv at home or school things tq find'but in other hooks (encouragingstudents to use the library, or to fmd data from other sources) things to write about to enmurage creative writing points to discuss and making decisions to suggest debate topics and other activities questions to answer to give practice in answering test questions
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Journal of Chemical Education
1 The teacher demonstrates lthe fractional distillation of /theoil. and the students .nvest gate the propenes of the proouns maoe lrom tne alflerent fractlons
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I Making the Most of Your Pet!
Winning Oil The students learn how oil is formed and how it can be trapped in the rocks. They use evidence from core samples to locate an oil trap and decide where to sink a well.
l ~ h stLaents e learn abo~ttne man~fact~re of PET oonles. ano tney wnsloer tne wsrs lnvolveo n n n n ng a scneme to recycle them.
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The students learn that synthetic detergents are made from oil and that their molecules are designed to disperse grease. They then consider whether to use
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What Are Oil Products Made of? discovery that oil and its products are hydrocarbons. The students build models of simple alkanes.
When the Oil Runs Out? their lives would change if no oil products were available. They learn how coal was used as a source of chemicals and explore ways in which chemists might make better
of What We Want The students crack liquid paraffin. They learn about the reactions of alkenes and investigate the structure of these compounds usma molecular models.
1 F gure I. An overall p an for teacnmg the un 1 Makmg use of orlm the Sahers' Sc~encecourse (2). Each lesson 1s outllned in a box
I t was a very interesting experience writing the books because they exert a discipline that was exacting but very rewarding. Transporting Chernical+An
Example Unit
Figure 3 outlines the 16 units in Salters' Chemistly Course. eivine the theme. the chemical ~ r i n c i ~ l eand s . the teachigstra&ies. One of these, lFansportini chemicals, which is taught fairly early in the course (sixth), is used a s a specific example (14). This unit introduces chemical symbols and formulas a s the main scientific concept and safety
as t h e m a i n technological idea. It also covers some indust r i a l processes.
Lesson Plan--Making Use of Oil What Else Can We Get from Oil?
Terminology a n d Concepts
Crude oil is used to mane more tnan fuels and polymers. Th s lesson is a b o ~nonsoapy t detergents. The SlLoents learn aboJt lheir molecular structures, how they work, and what advantages lhey have over soapy detergents. They compare the performanu ~f two liquid hand and body soaps--only one of which is environrnent-friendlv. Then thev decide whether it is worth buving . - this new kind of product. .
Activity
Outline
Key Points
Teacherstudent discussion
Students are reminded that one way of clearing up an oil slick is to use detergent. The meaning of the term detergent is discussed, and the distinction is made betweensoapyand nonsoapy detergents. The students learn that both sorts of molecule will disperse grease.
Detergents disperse oil and grease, and they can be used as cleanin( agents Soapy delergents are made by reac Ing anlrnal or vegetab e fat w th alka honsoap! detergents are usually made from hydrocarbons in crude oil. Both types have similar molecular structures.
The~-~~~ students- shake soapandnonsoapy detergems w l h haro and son water.
Soaov deteraents form o~ haro water, wnereas nonsoapy detergents latner n a l types of water.
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Planning The students compare It is possible to compan the effect of shaking oil the performance of two an investigation with water to shakina oil deteraents bv settino ur with a solution of deiegent. They then plan and carry out an investigation to compare the effectivenessof an environment-friendly liquid hand and body soap with a conventional one. Text-related The- students ~- read how activity chemists have worked to perfect the design of synthetic detergents principally to ensure biodegradability. They learn that, in addition, some detergents claim to be environmentfriendly. They compare the performance of this type with a conventional detergent.
Thanks to the work of cnem sts, al modern oetergenls are o ooegraoable. Many Iq~onandanooody soaps, marketed as friendly, are made from vegetable oil rather thal crude oil. They biodegrade very quickly and make use of a renewable resource.
The students write a report about choosing a liquid face and body soap for a consumer magazine.
When choosing a deter. gent product, consumers might ask these questions: HOWeffective is it? .How quickly will it biodegrade? Does it use afinite or a renewable resource?
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Homework suggestion
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To start, students look f o r a n d "collect" t h e h a z a r d signs o n r o a d tankers, m u c h as children collect oubof-state license plates o r types o f cars o n a u t o t r i p s . T h e h a z a r d codes c o n t a i n t e r m s such as poison, corrosive, i r r i t a n t , spontaneously combustible, a n d dangerous w h e n wet. T h e n t h e teacher can show t h e class some o f t h e chemicals involved u s i n g demonstrations. T h e teacher i s also given a set o f slides that show various ways in w h i c h chemicals are transported by road, rail, ship, and air.
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T h e second lesson covers necessary emergency services.
A problem-solving activity, Hour to deal with a spilluge of oil, can b e used. T h i s i s a n activity l a b for students. They are given a b o w l containing water w i t h some o l d sump o i l floating o n it. Several methods can b e tested: dissolving t h e o i l i n a solvent, scraping, absorption in sawdust, burning, use o f detergents, a n d use o f a scparatlng funnel. T h e n s t u d c n u d~scusswhich of these methods would he effective b n a large scale. Using Printed Chemical Information Discussion o f t h e symbols found o n r o a d tankers, w h i c h are a Dart o f a n international lanrmaze. leads t h e class to a n o t h k r i n t e r n a t i o n a l language: symbols a n d formulas. The students are shown extracts f r o m texts f r o m different countries t o emphasize t h i s point. P l e n t y of t i m e i s allowed v z i n n i n f o r m a t i o n about various chemical ~ r o f o r a n a l. cesses a n d for g a i n i n g experience in a b s t r a c t i n g data. T h e n t h e class moves o n to t h e n e x t activity.
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Role Playing
At t h e e n d o f t h e unit, students in s m a l l groups have a role-playing exercise, each t a k i n g different p a r t s in a story in w h i c h a chemical company wants t o transport b u t a n o l across t h e countryside. E a c h student i s given a b r i e f m g sheet for t h e roles, w h i c h include t h e owner o f t h e r o a d tanker, a rail freight manager, a shipping agent, local residents, a n d representatives f o r t h e i n d u s t r i a l companies concerned. S t u d e n t s discover w h e n v a l u e j u d g e m e n t s m u s t b e made a n d w h e n h a r d chemistry evidence m u s t be used.
Summary T h i s unit illus€rates t h e a ~ ~ r o a c Bv h . t h e e n d o f it--8 hours work-students have worked &h each other f o r a n s i m i f i c a n t amount o f time. T h e y have seen chemistrv i action because t h e unit i n t r o d i c e s some o f t h e ways in w h i c h chemicals differ in b o t h physical and chemical properties. The unit also lays t h e basis of symbols and formulas in a n interesting way-a w a y t h a t t h e y enjoy, t h a t helps t h e m t o l e a r n quickly and effectively
Literature Cited 1. Salters'lnstitute ofIndustcia1Chemistn. an educationalchar5ttofththSalters'Company, a tivery company in the City ofLandon. 2. ForSolfers'Sclone~PI~~lplpl,"riteMidlandExsminingGmup(UCLES). IHilhRoad, Camblidge CB1 2EU, UK For Salters' Chemkfry Project Midland Examining Group ITWEB), Norfolk House, Smsllbmk, Queansway, Birmingham B5 4NJ, U K For Soifers'Aduonced ChAmkLry Pmject, O d d and Cambridge Schools Ex. amination B o d . Pvrbeck House, RvbeekRoad, Cambtidge CB2 2PU. UK 3. Holman. J. S. Chem inBluhin 199127.818414. , ,~ 4. Burton, W. G.; Holman, J. 3.; m h g , 0. M; Waddington, O.J. to be published. 5. "Food Rocwsing' lm Tha Solters'ChemkLry Course Unit Duido,WSEG:York, 1981. 6. ~ i g h t i n gxsease~n ~ h saltprs' chomishy course unn cuido:WSEG: york, 1987. 7. "Bui1dings"InTheSaltars'Chrmishy Course Unit Guuio;WSEG:York, 1987. T o n struction Materials" In The Solfers'SelDneeCoursp Unit GuSq Heinemann Educational:Oxford. 1990. ~
Figure 2. A lesson plan from Making use of oilin the Salters' Science course (2).The left-hand column briefly shows the range of activities in the lesson. The right-hand column shows the key chemical ideas that can be illustrated
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Volume 69
Number 11
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November 1992
901
The Salters' Chemistry C o u r s e The course is Dresented throuah these 16 unit auides for teachers. The content of each unit is brieflv summarized below. " tne propenles, uses, ana care of ftbers and faorlcs, Inc uo ng ayelng, flameproodlng,and waterproofmg It lntroouces oeas of po ymer zatlon and the re attonsn p of molecdlar strLctJre and o ~ l kproperttes n lloers Act v tles InclLoe dala sLrveys, use of molec~larmodels, and pract ca lnvesllgat ons A survey of the things we drink leads to studies of the safe supply of domestic water and the production of different kinds of Drinks drinks. The particulate nature of matter, the concept of pure substances, and methods for separating mixtures are introduced. Acitivities that may be based on this unR include visits to water or sewage works, practical work on filtration, evaportation, distillation, and fermentation, and consideration of factors in the commercial marketing of drinks.
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S t ~ d yof the mponant components of foods leads to consloerat on of d~etand healthy eat ng, end ng wltn a cons~derauonof food preservatwes and other addltwes O~aldattveanalys s for food components and data analysis, mcl~dmgtne use of data bases, are covered in this unit. Choice of material for a teaspoon leads to considering the range of the properties of metals, the protection of metals from Metals corrosion, and the uses of alloys. The reactivity series is introduced, along with ideas about corrosion as an oxidation process. Analytical testing and open-ended investigations of rusting are the activities. Our use of v a r ~ o ~ f s~ se s stualed througn a searcn tor "the laeal f ~ "eSt~dentss r ~ o ytne f re tr angle, the chem s t y of Warmth combusl~on,an0 me elfens of large-scaleuse of f ~ e l sComparauve tessng, data ana ysls. and ways of reportang pol ut on I issues feature as activities Transporting The hazard-warning signs on road tankers introduce the use of codes to convey chemical information, and the use of Chemicals chemical symbols, formulas, and equations. Surveys of the manufacture, properties, and uses of some major industrial chemicals reveals the ranae of chemicals that are transwrted. Ideas from the unit are drawn tooether in a role-~lavina exercise to select the besimethod of transporting a pariicular chemical. A survey of bJlldlngs leads to a of stuoy of !he propenles of bJlldlng matena s Re atlonsh ps oetween molecLlar StrJcture BJ Id ngs and b ~ l propert k es are exammed. lnclJdlng ceram cs, glass, pa~nts,metals. and wood There are opportun tles to Jse Keys to classify substances and to design experiments. Case studies of baking, the effect of cooking on vitamin C, the browning of apples, and the manufacture of margarine Food Processing introduce activities of chemists in food preservation and improvement. The chemical structure of fats and oils, including unsaturation, the chemistry of raising agents, and the function of vitamins are studied. Practical activities include chromatography, the preparation of esters, and an investigation of emulsifying agents. Food
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Growing Food
The need to feed the World's population leads to a study of fertilizers and agrochemicals. Chemical principles encountered include the formation of salts, quantitative calculations of the yield in chemical reactions, and the nitrogen cycle. Practical activities include preparation of salts and an investigation of fertilizer leaching. There is also a data survey and discussion activities.
Keep~ng Clean
Soaps, detergents, snampoos, and toothpaste are feat~redn t h s un t Haraness of water, aetergency, and the actlon of emu slfylng agents are stud ea Sl~aentsprepare a range of products lnvestlgatlons cu mlnate in a market ng exercse base0 on cleaners formu ated by tne st~dents
Minerals
A general introduction to minerals and the environmental issues related to their exploitation leads to more detailed studies of sulfide ores, iron ore, limestone, and bauxite. Techniques of mineral separation and the extraction of metals provide an introduction to the periodic table and a revison of calculations of reacting masses. This unit features role playing and data interpretationas well as practical work. A sdrvey of the uses of plastcs eaas to tne study of the r formL at on and properties Tne cnemlstry of tne format on, exlractlon, and processing of crude 011leads to stud~esof structJre and bond ng in s mple organ c mo ecules ana polymertzat on A varlery of act v nes ~ n c l ~ o the e s use of models lo lustrale mo ecLlar strJclLres
Plastics
Burning and Bonding
I EnergyToday ana Tomorrow Fighting Disease Making and Using Flertricitv
Fire hazards, fire fighting, and flash points introduce the energy changes in chemical reactions. Energy changes in bond making and breaking, activation energy, and energy diagrams are used to explain exothermic and endothermic reactions. Understandina of the relationship between twes of bonding and bulk properties is revised and extended. A series of practical experiments is supported by theuse of molecular models A sruoy of energy Lse and resources leaas to cons deration of a Herent soLrces of energy an0 tne implicat ons of the r Jse. Photosynthes s, tne prod~clionof b omass f ~ e l scombustion , an0 its enen on air q~ality.the StrLctJre of the atom, rad oanivity. and tne proo~nionof electr c ty n nuc,ear power stat ons are stJdle0. The role of chemists in heaNh care is studied through work on germicides, enzymes, and drugs. Practical investigation of the effect of bleaches and conditions that affect enzyme action are illustrated using models and data base exercises. Electrical energy can be obtained directly from chemical change. Simple and rechargeable cells and examples of electrolysis. including the extraction and anodizing of aluminum and the production of chemicals from salt, are studied.
Figure 3. The units in the Salters' Chemistry Course (3
The Salted Chemistry Course Unit Guide WSEG: Yark. 1981. Thx Solfers'S&m Course Unif GuMq WSEG:Ymk. 1989. 9. %en Machine' In Tha S o l a m ' s e k m Course Unit Cuidr, HeinemEduca. Bond: &ford. 1990. -~~ 10. Garfolth. F.M.Edue in S e k n a 1984,108.21; T i m ~ i E d u cSuppl. 1986,3586.62; Em+y Chemistry, Pmeeedulgo, Chem. Ed., Ireland, p 4 1986; Chllds. P.E., Ed. (alluding, of cornme, to C m U . L Thmugh the Lmking & and Whof Alice Found Them: 1871). 8. .DrinhsmIn
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~ 3 1G. , c.; ~ o h n a nJ, . s.;~ a ~ o nJ. b N.; ~ , ~affan,J . G. A.; wad-", D J. ~ ~ ducing Chemislw: The Sdters'Appmoeh, Hevlemann Educational: Olford, 1989. 12. Hill, G. C.; Holman, J. S.; heonby. J. N.; Raffan, J . G.A,; Waddington, D. J. Cheistry: The Saltom'Ap~moch;Heinemam Educational: &ford, 1990. 18. Campbell, R. M.; Laronby, J. N.; Millar, R. H.; Smyth S. S e b m : The Sultem'Appmoch; Heinem- Edwationd: &ford, 1990. 14. 'Transporting Chemieala" In Tha Saltem'Chsmistry Covrse Unit G u m WSEG. Ymk, 1987.
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