HKASME Science Assessment Test B. It is a saturated solution. (41%) C. It contains undissolved X....

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Transcript of HKASME Science Assessment Test B. It is a saturated solution. (41%) C. It contains undissolved X....

  • 2017/7/6

    1

    HKASME Science Assessment Test 2017

    DATE: 6 JULY 2017

    (Debriefing Seminar)

    HKASME Science Assessment

    Test Purpose:

    • To develop and to implement a science assessment test for S2&3 students in Hong Kong

    • To analyse the test results and to provide feedback to schools/the administration on the strengths and weaknesses of students in learning science

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    2

    HKASME Science Assessment

    Test

    • Duration: 1 hour

    • Paper Structure:

    Section A: 24 MCQs

    Section B: 2 Short-response questions

    • Coverage: Science knowledge in

    topics 1 to 11 of CDC Science Curriculum

    S1 to S3

    2017 Science Assessment Test

    • Bronze Award based on a criteria-based model

    • Introducing a Diamond Award (top 5%)

    • Expert judgment for Gold, Silver and Bronze Award

    • QP and students’ performance on individual questions available to participating schools

    • More informative school reports

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    3

    Participations in 2017 SAT

    No. of Participating Schools: 88

    Participants S1 S2 S3 Total

    Boys 14 622 654 1290

    Girls 6 574 532 1112

    Total 20 1196 1186 2402

    Science Process Skills

    • Observing, measuring and recording data (SP1)

    • Comparing and classifying (SP2) • Planning and designing (SP3) • Experimenting (SP4) • Interpreting data / Inferring (SP5) • Communicating (SP6)

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    4

    Weaknesses of Participants as

    Revealed from Their

    Performance

    Section A

    Discrimination index (DI)

     describes the ability of an item to distinguish between high and low scorers

     ranges between -1.00 and +1.00

     expected that the high-performing students select the correct answer for each item more often than the low-performing students

     DI = (H-L) / ½ N

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     items with p-value between 30 - 70 and DI > 0.24 

    “appropriate”

    Understanding and Interpreting

    Graphical Information

    The graph below shows the variation of solubility of a

    salt X with temperature:

    Q.12

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    In an experiment, 40 g of X is added to 100 g of water kept at

    60oC and the mixture is stirred until there is no further change.

    Based on the above information, which of the following

    statements about the resulting mixture is correct?

    *A. It is an unsaturated solution. (42%)

    B. It is a saturated solution. (41%)

    C. It contains undissolved X. (13%)

    D. It has a mass of 100 g. (4%)

    Less than half of the participants were able to choose the key

    showing that they were weak in the interpretation of graphs.

    Discrimination index = 0.56

    Q.19

    An experiment using the set-up

    shown on the right can be used to

    study the pressure-volume

    relationship of a fixed mass of air at

    room temperature.

    Pressures (P) of different

    magnitudes are applied onto the

    plunger and the corresponding

    volumes of the air inside the syringe

    (V) are measured. Which of the

    following graphs correctly

    represents the experimental results

    obtained?

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    V

    P

    V

    P

    V

    P

    V

    P

    A majority of the participants knew that, under constant

    temperature, the volume of a fixed mass of gas decreases with its

    pressure. However, most of them did not know that the volume-

    pressure relationship is non-linear.

    Discrimination index = 0.22

    Understanding of Abstract Science Concepts

    Q.7 Toby throws a ball in air at an angle. The diagram

    below shows the path of the ball and four positions, P,

    Q, R and S, of the ball along the path:

    In which of these positions, does the arrow represent the

    direction of the force acting on the ball? (Assume that there is

    no air resistance.)

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    A. P (17%)

    B. Q (54%)

    C. R (12%)

    *D. S (17%)

    More than half of the participants wrongly thought that the

    direction of the force is tangential to the trajectory of the ball.

    They did not realize that when the ball had left Toby’s hand,

    the pushing force (a contact force) would cease to act on it,

    and the only force acting on the ball was the gravitational

    attraction (a non-contact force).

    Discrimination index = 0.58

    Q.15 Peter used the set-up shown below to study the image

    formed by a convex lens:

    He moved the lens to and fro until a sharp inverted

    image was formed on the screen. If Peter repeats the

    experiment using a thicker convex lens, which of the

    following combinations correctly describes the position of

    the lens and the appearance of the sharp image formed?

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    Position of the lens Appearance of the

    image

    *A. closer to the screen remains inverted (42%)

    B. closer to the screen becomes upright (13%)

    C. further away from the

    screen remains inverted (36%)

    D. further away from the

    screen becomes upright (9%)

    Nearly 80% of the participants knew that, under the

    experimental conditions, an inverted image would be

    formed. However, quite a number of them failed to realize

    that a thicker convex lens bends a beam of light to a

    greater extent and forms an image closer to the screen.

    Discrimination index = 0.37

    Classification of Animals

    Q.14 Consider the animals shown below:

    Which of the following features of these animals can be used

    to classify them into two groups?

    (1) whether or not they live in water

    (2) whether or not they have antennae

    (3) whether or not they have wings

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    A. (1) only (12%)

    B. (2) only (5%)

    C. (1) and (3) only (56%)

    *D. (2) and (3) only (27%)

    A majority of the participants recognized that ducks

    and flies have wings while elephants and frogs do not.

    However, quite a number of them did not know that

    frogs are amphibians, and some failed to realize that

    flies do have antennae.

    Discrimination index = 0.35

    Weaknesses of Participants as

    Revealed from Their

    Performance

    Section B

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    Question No.

    Mean S.D.

    1 3.0

    (30%) 2.13

    (21.3%)

    2 4.6

    (58%) 1.79

    (22.4%)

    Overall 7.7

    (43%) 3.28

    (18.2%)

    • Q.1 - to test participants’ understanding of

    experimental procedures, communicative and

    graph-plotting skills, and interpretation of

    experimental data

    • Q.2 – to test participants’ understanding of scientific

    methods, the design of fair tests and the various

    factors that affect a fair comparison

    B1 Question on Data-handling

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    (b) Word equation: chips + oxygen → carbon dioxide + water + energy

    No. of

    response

    s

    %

    10 All correct 313 13.0

    11 Replacing oxygen with air 2 0.1

    12 Replacing energy with heat (熱/熱能) 252 10.5

    13 Replacing oxygen with air and energy with

    heat 5 0.2

    90 Failure to give both (answers other than

    oxygen/air & energy/heat) 590 24.6

    91 Giving oxygen/air but failing to give

    energy/heat 138 5.7

    92 Failing to give oxygen/air but correctly

    giving energy/heat 1053 43.8

    93 Using O2 for oxygen & E for energy 2 0.1

    99 Nil response 47 2.0

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    90

    92

    (c)(i) Plot a graph to show the relationship

    between ‘the mass of potato chip burnt’

    and ‘the temperature rise of the water in the

    boiling tube’.

    Three aspects were looked for in marking the graph:

    • correct labeling of axes (code: A1x, A9x);

    • appropriate choice of scale (code: S1x, S9x); and

    • joining the points with a straight line (code: G1x,

    G9x).

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    No. of responses %

    A10 Plotting ‘temperature rise of water’ against ‘mass of potato chips burnt’, and both axes are correctly labeled with correct units

    547 22.8

    A11 Plotting ‘temperature rise of water’ against ‘mass of potato chips burnt’, and both axes are correctly labeled with some units (g/oC) missing

    40 1.7

    A12 Plotting ‘mass of potato chips burnt’ against ‘temperature rise of water’, and both axes are correctly labeled with correct units

    240 10.0

    A13 Plotting ‘mass of potato chips burnt’ against ‘temperature rise of water’, and both axes are correctly labeled with some units (g/oC) missing

    22 0.9

    A91