A/AS level Chemistry TAS
Workshop for Teachers
18 October 2007
1
Teacher Assessment
Scheme
 Practical paper of the A/AS level
Chemistry Examination
 20% of the subject mark
 Compulsory to all school candidates
(including first-timers and repeaters)
 Private candidates : either (i) use
previous TAS result , or (ii) take
practical exam
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TAS allows:
 better link between theory and practical





work
students to experience a wider range of
experimentation
the assessment of a full range of practical
abilities
reduction in examination pressure
teachers to provide frequent feedback to
students
increase in teachers’ professionalism
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Requirements of TAS
 Lab work should cover different
areas and types of experiment
Area : CH, EQ, KI & EN
Type:
P, QL and QN
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Requirements of TAS(cont’d)
 Number of experiments
A-level
15 experiments in S6
8 experiments in S7
AS-level
13 experiments in 2 years
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Requirements of TAS(cont’d)
 Ability area A  Manipulative skills, skills in
observation and general bench
performance
 Presentation of data,
 Ability area B
interpretation of results,
planning of experiments and
project work
 Ability area C  attitude towards practical
chemistry
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Minimum requirement for each candidate
A-level (First-timer)
No. of Assessment Marks reqd.
Ability
area
S6
S7
A
>2
>1
>4
B
>2
>2
>4
C
1
1
2
Over the two years
>10
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Minimum requirement for each candidate
AS-level (First-timer)
No. of Assessment Marks reqd.
Ability
area
S6
S7
A
>1
>1
>2
B
>1
>1
>2
C
1
1
2
Over the two years
>7
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Repeaters & transferred candidates in TAS
Students who join S7 chemistry
classes directly in the year of
repetition or transfer.
 Ignore all their previous TAS marks
or practical examination marks.
 Make assessment as follows:

A-level :
minimum 3A, 3B and 1C
AS-level : minimum 2A, 2B and 1C
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Making assessments
 Assess each student sufficiently on each
ability.
 Not necessary to assess all students on
the same day and on the same
experiment.
 Assess as unobtrusively as possible.
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Making assessments (cont’d)
 Assess on a 10-point scale:
10-9
8-7
6-5
4-3
2-1
very good
good
average
weak
very weak
(Refer to Appendix III of TAS Handbook.)
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Making assessments (cont’d)
3 ways for allocation of marks:
(i) Mark Scheme
(ii) Impression
(iii) Overall impression over a longer
period of time, for a particular area e.g.
area C
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Project work in TAS
 Not compulsory
 Involve practical work and experimental
investigation
 Include:
 designing experiment
 performing the investigation
 writing the report
13
Project work in TAS (cont’d)
 One project = max. 3 experiments
 For each student, each project can be
used to assess 1A & 1B only
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Lab reports
 Language medium used must be the
same as that chosen for the written
exam.
 Detailed reports:
object of expt, chemical principles
involved, experimental method,
results, interpretation and discussion,
conclusion.
First-timers: 4 for AL and 3 for ASL
Repeaters: 2 for AL and 1 for ASL
 All reports should be marked.
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Information about TAS:
 Refer to Handbook on the A/AS Chemistry
Teacher Assessment Scheme
 HKEAA website: www.hkeaa.edu.hk
 Enquiry: 36288068 (Ms Tansy Chun)
36288025 (Mr CW Pau)
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Reminder
Always consult your group
coordinators when you have
queries or problems
17
Common problems reported
by coordinators
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(1) Unclear experiment titles
 E.g. (i) Project 1
(ii) To prepare a carboxylic acid
 Titles entered in the TAS assessment
records should be informative and
specific.
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(2) Insufficient no. of
preparative experiments
 Experiments indicated as P are not
preparative experiments.
Preparative experiments should involve
techniques such as:
handling of gases, filtration, crystallization,
recrystallisation, distillation, reflux, drying,
liquid-liquid extraction, purity control by
determining melting point / boiling point.
A minimum of 2 P experiments should be
carried out. (TAS Handbook)
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(3) Mark range too narrow / too
wide
 For each candidate, the mark awarded
should reflect the typical standard of
the candidate.
 For the whole class, the marks awarded
should be able to discriminate
candidates with different abilities.
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(4) Teacher changes
 Best to have more than one teacher
familiar with the Scheme
 Out-going teacher to hand over
his/her work on TAS to new teacher,
including:
 List of experiments and their handouts
 Records of TAS marks awarded to
students e.g. printouts of software
 TAS program, its passwords, and
backup diskettes, if any
 Inform coordinator of the change
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(5) Mark Adjustment
 Rank order of students in a class
will be preserved.
 Adjusted TAS mean marks
calculated from Written Paper mean
marks.
 TAS marks will be shifted
upwards/downwards.
 SD of TAS marks will be preserved.
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Skills to be tested in GCE A
Level Science Subjects
 P – Planning
 I – Implementation
 A – Analysing Evidence and
Drawing Conclusions
 E – Evaluating Evidence and
Procedures
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Questions & Answers
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