TAS in Chemistry AL ASL Chemistry Practical EDB

TAS in Chemistry (AL & ASL Chemistry Practical) EDB & HKEAA 18 October 2007

Programme 2: 15 Registration 2: 30 Learning and Teaching of TAS Mr WH FONG, EDB 3: 00 Assessment Aspects of TAS Mr CW Pau, HKEAA 3: 30 Break 3: 45 Making Assessment Mr WH FONG, EDB and Mr CW PAU, HKEAA 4: 15 Experience Sharing Mr KB NG, Fukien Secondary School (Siu Sai Wan) 5: 00 Questions and Answers

Learning & Teaching in TAS

Improve Learning through Assessment l Key factors identified by research: the provision of effective feedback to pupils; l the active involvement of pupils in their own learning; l adjusting teaching to take account of the results of assessment; l a recognition of the profound influence assessment has on the motivation and self-esteem of pupils, both of which are crucial influences on learning; l the need for pupils to be able to assess themselves and understand how to improve. l Assessment for Learning: Beyond the Black Box Assessment Reform Group, UK

Why TAS? l Limitations of practical examinations Success depends on the methodical use of a limited number of well-practised skills. l Practical work in schools is usually geared to the nature of the practical examination, and hence may be limited in scope. l The full range of practical objectives is not tested. l A once-only examination may not measure true ability. l Teachers are not involved in the assessment procedure. l The examination does not provide feedback to the students, and thus has very little educational value. l

Why TAS? l Advantages of TAS Educational objectives are more directly and efficiently achieved by the necessary laboratory experiences and their associated assessments, through a better link between theory and practical work, and by encouraging a greater diversity in experimentation. l Examination pressures are reduced. l It is possible to assess the full range of practical abilities. l It provides frequent feedback to students. l It increases the professionalism and experience of teachers. l

Purpose of Assessment l Assessment for Learning 促進學習的評估 l Provide information about the progress of students in relation to knowledge and understanding, and various skills (continuous assessment) l Identify where emphasis needs to be made to the next stage of learning (feedback) Assessment Learning Teaching

Practical Skills Required / Optional in TAS? 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. Collection of gases Crystallisation Determination of melting and boiling points Distillation and reflux Filtration Handling of colorimeter, p. H meter and datalogging system Flame test Handling of simple electrical devices Liquid-liquid extraction Simple chromatography Use of electronic balance

Practical Activities Required / Optional in TAS? 1. 2. 3. 4. 5. 6. Students have to do a pre-laboratory quiz on theory and procedure. Students have to do a risk assessment before they can start their own experiment. Students have to planning one or two experiments, in TAS by writing formal proposals Students have to carry out one preparative experiment. Students have to write five detailed reports. Students have to present experimental findings orally in class, and in a written form.

Learning, Teaching and Assessment Which goes first? l Learning, Teaching and Assessment l Learning / teaching goes before assessment l provide sufficient instructions and practice l relate practical to theory l arrange practical as and when appropriate l provide feedback for learning e. g post hoc discussions on experimental results, procedures, sources of error, etc. l l TAS should be deployed for learning and teaching as well as assessment.

Teacher Assessment Scheme CW PAU, HKEAA

Break for 15 minutes

Making Assessment

Criteria in Assessing Area A Manipulative and observation skills, general bench performance 1. Methodical Working 有條不紊的 作 l 2. correct sequence of operations, efficient use of time, etc. Experimental Technique 實驗技巧 l correct & safe handling of apparatus & chemicals, and carrying out operations (observe students directly or based on comparison with target values)

Criteria in Assessing Area A Manipulative and observation skills, general bench performance 3. Skills in Observation l l read scales on instrument to the correct degree of accuracy correct observations (dichotomous judgement) recognise relevant and irrelevant observations use a control to tell whether a change has occurred (oral questions/written record) Manual dexterity手法熟練程度 5. Orderliness 4.

Criteria for Assessing Area A l 5 major areas Operation of a single piece of apparatus l Carrying out experimental procedures l Reading and measurements of different instruments / apparatus l Observational skills l General bench performance l l depends on the experimental situations (e. g. Acid based titration, kinetics experiment and preparative experiment are all very different in nature and involve quite different skills, hence different assessment criteria should be ued)

Example 1: Acid-base Titration Marks may be allocated by taking into account of the following: l Rinses out burette taking care to rinse jet l Clamps burette vertically l Fills jet of burette up before starting titration l Uses pipette filler correctly l Pipettes exactly 25 cm 3 of dilute sodium hydroxide l Transfers exactly 25 cm 3 of dilute sodium hydroxide to conical flask without spillage l Adds dilute sulphuric acid in suitable amounts from burette l Continually swirls the flask during the addition of the acid l Works safely l Works tidily (Earl & Wilford, Practical Assessment in Advanced Chemistry)

Example 2: Comparison of the rates of hydrolysis of haloalkanes Experiment Instructions: l Devise a small scale experiment to compare the rates of hydrolysis of the bromoalkanes given. l Write a brief plan of the experiment you intend to carry out and hand this to your teacher. l Carry out the experiment and using the evidence you obtain place three compounds in order of increasing rate of reaction. l At the conclusion of your experiment note any modifications you made while carrying it out and hand these to your teacher along with your derived order of reaction. (Earl & Wilford, Practical Assessment in Advanced Chemistry)

Example 2: Comparison of the rates of hydrolysis of haloalkanes l Assessment Criteria: Eye protection l Ethanol is used as a common solvent l Equal quantities of ethanol, haloalkanes, silver nitrate solution l Correct order of addition of reagents l Time from first addition of silver nitrate solution or haloalkane l Time for first precipitate to appear l Correct relative order of hydrolysis l Suitable modifications l

Criteria for Assessing Area B Presentation of data, interpretation of results, planning of expts 1. 2. 3. 4. 5. 6. Accurate recording of observations Present results properly and systematically Use correct units and appropriate no. of sig. fig. Understand principles; efficient calculations; & aware of sources of errors in quantitative work Recognise the reactions involved & draw relevant conclusions in qualitative work Student’s ability to plan and carry out experiment

Assessing Area B Presentation of data, interpretation of results, planning of expts l Assessed by l written reports, questioning, pre-lab quiz, post-lab quiz etc. Train students to organise and present their ideas in a logical and systematic manner l Students’ own words and reflect their understanding l Vary regularly the experiments like using different methods, samples to be tested, concentrations of solutions, indicators, etc. in the lab manual to avoid plagiarism l Feedback l l grades/marks/comments, helps students know their learning progress

Assessment Activity: Area B Criteria Weighting Clear account, proper use of chemical nomenclature & terminology, accurate spelling, punctuation and grammar 2 Correct & efficient calculations 3 Appreciation of data and major source of errors 2 Satisfactory answers to discussion questions 2 Draw valid conclusion by applying knowledge and understanding of Chemistry 1 10 Score

Allocation of marks 1. By a scheme of marking 2. By impression of the students’ work on a particular operation 3. By overall impression over a longer period of observation, for a particular area

Some Remarks on Assessment l Marking scheme vs overall impression l Be objective and unbiased l Prioritize skills to be assessed l Independent assessment of different skills l Cross check with general descriptor / criteria l Professional judgement l Better for teachers to develop their own set of assessment criteria (teacher professionalism) l Assessment Grid for recording of assessment results for a number of students in an assessment occasion

From Novice to Expert

Difficulty in Awarding Marks Q Some new teachers lack confidence in awarding a reasonable spread of marks and experience undue anxiety towards possible discrepancy in assessed marks across schools. A The essence of awarding marks is that teachers should be able to give a reasonable spread of marks, and arrange the students in a proper rank order. A Teachers need not worry about the discrepancy in the assessment marks across schools, as this can largely be taken care of by the moderation procedure.

Instant Lab Report Post lab reports - focus students’ attention on producing good finished reports l Reports at the end of practical l l students are likely to work faster, try to make more sense of what they are doing, make more observations and record them in better organised notes, and take more care when recording data, pick up obvious errors, time to do the work again and correct it Adjust the assessment criteria so that full recording of procedures and results will carry more weight than neatness l Free students afterwards to do something more constructive l More reliable assessment results l Frequency? l (Habeshaw et al, Interesting Ways to Assess Your Students)

Planning Experiment l Experiments: not just doing; should involve thinking (stimulate and challenge pupils) l Students should try to understand the relations between evidence gathered and relevant theory (facilitation provided) l Cognitive skills: l Recall & Understanding (explain) l Higher Skills (analysis, synthesis & evaluation) l Example: Decomposition of Na. HCO 3

Incorporating Inquiry into Experiments Inquiry - an active engaging process that mimics the work done by actual scientists (NSTA) l Choose experiments that l address simple concepts l can be completed using familiar equipment l can be safely conducted e. g. microscale l where the data can be pooled by the class and leads to final results l Require students to design some or all of the procedures (ownership and motivation): autonomy l Increase the opportunities for students to think about the data they should collect and their presentation l

Sources of Inquiry-based Experiments l Exemplar Individual Investigations, Salters Advanced Chemistry (http: //www. york. ac. uk/org/seg/salters/chemistry/investigations. htm ) l l Inquiry-based Experiments in Chemistry l Calculating Heat of Solution l Identifying Unknown Solutions l Brown versus White Eggshells l Effect of Temp on the Rate of a Clock Reaction Creative Problem Solving in Chemistry l A Black Solid (C & Cu. O) l Making Copper (from Cu(NO 3)2)

TAS Project Work l Project-work: l Practical-work based l Involves planning, performing and presenting in a written form l Equivalent to one “A” and one “B” l Open-ended vs Guided Project: A continuum l Group project: OK l Try out of TAS project work and be prepared for NSS Investigative Study

Operating TAS How much should students be informed? Application for operation of new course (via REO) and 1 st participation in public examination (via HKEAA) l Laboratory facilities and equipment l Choosing experiments l l Syllabus suggestions, TAS requirements Educational value, safety, availability of chemicals & equipment, teaching time, etc. l Variety, Cook-book or Inquiry based l l l Arrangements l l Tryout of expts, coordination with LTs, oral and written instructions to students, distribution of chemicals & equipment, laboratory reports, etc. Students with physical disabilities

Resource Materials for TAS

Practical Chemistry Resources Exemplars of Learning & Teaching Activities for Sixth Form Chemistry Curriculum (http: //resources. edb. gov. hk/~science/chem. htm) l Resource Book for Sixth-form Practical Chemistry, CUHK (http: //www. chem. cuhk. edu. hk/ssc. htm) l TAS Corner (http: //www. edb. gov. hk/cd/sc) l 高級程度化學實驗資料冊 l Reference Books (Adv Practical Chem, NAS, Classic Chem Expts, ILPACs etc) l l Internet Resources (e. g. Dr David Brook’s website, Nuffield’s websites) Datalogging expts, Diocesan Girls’ School (http: //www. dgs. edu. hk/QEF_Sc/Chem/experiments. htm) l Journals l l l Chem Review Chem 13 News (http: //sciborg. uwaterloo. ca/chem 13 news/index. html) Education in Chemistry 化學教學

http: //resources. edb. gov. hk/cd/science/ chemistry/TAS_corner/html TAS Corner

Videos on Practical Chemistry Demonstrate a new technique during lab class l As a resource for students in pre-lab assignments l As a review of a specific technical procedure l Quality assurance of laboratory techniques l l http: //cd. edb. gov. hk/sci/chemistry/tas/videos. htm (ETC and CUHK)

Microscale Chemistry Expts R. G. Silberman & L. T. Eubanks. (1996). ACS Small-scale Laboratory Assessment Activities. ACS. l Microscale equipment and methods l reduce time and expense l become possible to develop activities that test a students’ “laboratory thinking skills” and use problems posed in the laboratory as true assessment tools l

Thank you!