HKDSE Exam Guide(English)

Contents 1

Introduction Introduction to HKDSE

Part I

1

Public examination

2 Types Types of questions in the HKDSE exam paper

4

3

General exam skills

6

4

Skills in answering MCQs

10

5

Skills in answering essay questions

11

6

Skills in plotting graphs

13

7

Skills in drawing biological diagrams

14

8

Skills in studying biology

16

Part II School-based assessment (SBA) 9

About SBA

20

10 Basic experimental techniques

21

11 Skills in writing investigation investigation reports

25

1

Intr oduction tto H HKDSE

HKDSE (Hong K ong Diploma of Secondary Education) examination is a public assessment aiming to assess the attainment of candidates who have completed the 3-year senior secondary course.

A Mode of assessment HKDSE examination in Biology and Combined Science (Biology) comprises t wo components: public examination and school-based assessment (SBA). Biology Public examination Paper 1

SBA Paper 2

Curriculum coverage

Compulsory part

Elective part

Whole

Assessment tasks

Section A: Multiple-choice questions (36 marks)

Structured questions

Practical related tasks

(40 marks)

Section B: Short questions, structured questions and an essay question (84 marks) Number of questions to be attempted Duration

All

2 out of 4

2 h 30 min

1h

S5 & S6

20%

20%

60%

Weighting

(Section A: 18%; Section B: 42%)

Combined Science (Biology) Public examination (one paper only)

SBA

Curriculum coverage

Whole Combined Science (Biology)

Whole

Assessment tasks

Section A: Multiple-choice questions (24 marks)

Practical related tasks

Section B: Short questions, structured questions and an essay question (56 marks) Number of questions

All

to be attempted Duration Weighting

New Senior Secondary Mastering Biology (Second Edition)

1 h 40 min

S5 & S6

40% (Section A: 12%; Section B: 28%)

10%

1

© Oxford University Press 2014

B The reporting system HKDSE makes use of standards-referenced reporting (SRR) (水平參照) of assessments. The candidates’ level of performance will be reported as five levels (1– 5), with 5 being the highest. A performance below Level 1 will be designated as ‘Unclassified’ (U). The Level 5 candidates with the best performance are awarded a 5**, and the next top group of candidates are awarded a 5*.

5**

5* 5 4 3 2 1

Each level has a set of descriptors (等級描述) to describe what a typical candidate at this level is able to do. Details of the descriptors and samples of candidates’ performance of different levels in the past HKDSE examinations can be found at the HKEAA’s website.

 http://www.hkeaa.edu.hk/en/hkdse/assessment/subject_information/ category_a_subjects/hkdse_subj.html?A2&2&5


2


Par t II Public e examination


3


2

Types o of questions iin tthe HKDSE e exam p paper

1

Multiple-choice questions (MCQs)



For Biology, there will be 36 MCQs in Paper 1 Section A.



For Combined Science (Biology), there will be 24 MCQs in Section A of the paper.



Each question scores 1 mark.

2

Short questions



Each short question scores about 2 – 7 marks.



There are various types of short questions. Some examples are shown below.

a

Fill-in-the-blanks

Sample q question Amino acids are made up of carbon, hydrogen, oxygen and (a) ______________. Each amino acid molecule contains an amino group and a (b) _____________ group. A (c) _____________ is formed when two amino acids combine together. It can combine with more amino acids to form a long chain called the (d) ______________ .

b

Matching

Sample q question For each cell structure listed in column 1, select from column 2 one phrase that correctly describes its function. Put the appropriate letter in the space provided. Column 1 Mitochondrion

Nucleus

Cell wall

(3 marks)

Column 2 ________

________

________

A.

Encloses the cytoplasm

B.

The site of energy release during respiration

C.

Controls activities of the cell

D.

Supports and gives shape to the cell

E.

Contains organelles

In addition to the above types of short questions, some short questions begin with diagrams, photographs, graphs or tables of data, which are followed by a few questions.


4


3

Structured questions



Each structured question scores about 7 – 12 marks.



Structured questions are usually divided into parts (a), (b) and (c), etc. Each part may be divided into smaller parts (i), (ii) and (iii), etc.

Sample q question The diagram below represents a cross section of a flower.

(a)

Name structure P and state its function.

(b)

Using the letters in the diagram, state where

(c)

(2 marks)

(i)

meiotic cell division takes place.

(2 marks)

(ii)

fertilization takes place.

(1 mark)

State the fate of structures P, Q, R, S and U after fertilization.

(5 marks)

4

Essay questions



For both Biology and Combined Science (Biology), there will be an essay question in the exam paper. It scores about 10 – 12 marks.



In the total mark of the essay, 3 marks are awarded for effective communication.

Sample q question Compare the prophase in mitosis and first meiotic division. In what way does the difference in the prophase of first meiotic division affect the products of meiotic cell division? (11 marks)


5


3 1

Gener al e exam s skills

Time allocation

Subject

Biology

Combined Science (Biology)

Exam paper

Paper 1 Section A

Paper 1 Section B

Paper 2

Section A

Section B

Mark

36 marks

84 marks

40 marks

24 marks

56 marks

2 h 30 min

Duration Answering whole section

Suggested time allocation

1h

1 h 40 min

30 min

1 h 40 min

50 min

20 min

65 min

Checking whole section

5 min

15 min

10 min

5 min

10 min

Answering ONE question

50 s

310 min*

25 min

50 s

310 min*

* depends on the mark of each question

 Do the easiest questions first to build up your confidence. Do not spend too much time on answering a difficult question. Either give it up or save it for the last.

2

Understanding command words in questions

Before answering a question, you should look for the command word in the question. It tells you what you should answer. Below are some common command words in exam questions.

Command word

Point to note

Example of exam question

Calculate (計算)

Remember to show the working steps and give the answer a right unit.

According to the information given, calculate the rate of water absorbed by the plant.

Comment (評論)

You need to present an informed opinion.

Comment on the significance of the relationship between the structures for gas exchange and water transport in terrestrial flowering plants.


6


Command word

Point to note

Compare (比較)

Give both similarities and differences. Try to use comparative words like larger, smaller, etc.

Example of exam question

Compare the structures of a bacterial cell and a yeast cell.

Contrast (比較……的差異 ) Give the differences only.

Contrast the processes of mitosis and meiosis.

Deduce (推斷)

Deductions must be made based on the information given.

Based on the results of the cross, deduce which phenotype is recessive.

Describe (描述)

No explanation is required.

Describe how insulin can bring about a decrease in blood glucose level.

Determine (測定)

Your answer should be based on the information given.

According to the data given, determine the concentration of the insecticide at which 30% of mosquitoes are killed.

Discuss (討論)

Give arguments for and against Discuss the pros and cons of an issue and provide explanations. producing human insulin by genetic engineering.

Distinguish (分辨)

Give the difference between two things.

Distinguish between food-borne infection and food poisoning.

Explain / Account for ( 解釋) Give reasons.

Explain / Account for the increase in the length of a potato strip that has been put into distilled water for one hour.

Give / State (寫出／指出)

No explanation is required.

Give / State two functions of proteins in the human body.

Identify (辨認／鑑定)

Give the name and make sure the spelling is correct.

Using the dichotomous key given, identify animals A and B.

Label (標示)

Make sure the spelling is correct.

Label the cells shown in the photomicrograph.

Name (寫出……的名稱)

Make sure the spelling is correct.

Name the type of cell division occurring in the gamete-producing cells in human ovaries.

Outline (概述)

No detail is required.

Describe the major steps in recombinant DNA technology and outline their principles.

Suggest (提出)

Put forward your ideas.

Suggest two preventive measures that we can take to reduce the risk of contracting dengue fever.


7


3

Following the instructions

You must follow the instructions to answer the questions. Below are some examples of instructions.

Instruction

What to do?

Using the letters in the diagram, …

Answer with the letters provided in the diagram, not the names.

With reference to the photomicrograph, …

Use the photomicrograph / diagram provided to arrive at the answer.

Referring to the diagram, … State one other cause of …

Give another cause that is different from the one stated in the question.

Use a genetic diagram to show the result.

You must include a genetic diagram.

Explain your answer without using a genetic diagram . On the contrary, DO NOT use a genetic diagram to arrive at your answer.

Deduce, with reasons, the genotype of … Marks will not be awarded for genetic diagrams .

4

Communicating effectively

In answering structured questions and essay questions, express your ideas s ystematically and logically. Make good use of linking words to link different ideas. For example: Command word

Linking words

Describe … (about a graph)

Between … and … / From … to …

Outline the steps …

Firstly … Secondly … Thirdly … Finally

Give examples of …

For example / This includes … / … such as …

Contrast …

… however / while / whereas … / In contrast / On the contrary …

Explain / Account for …

Since / Because … So / Hence / Thus / Therefore / As a result …


8


5

Avoiding common mistakes

a

Spelling mistakes

When doing ‘fill-in-the- blanks’, or when you are asked to name, identify or label a certain structure, correct spelling is required. The key words in long answers must also be spelt correctly. Below are some commonly misspelt words.

Correct

b

Wrong

Correct

Wrong

amnion

amino

nuclei

nucles

dietary fibre

diary fibre

pancreas

pancrease

gastric juice

gastic juice

phloem

pholem

membrane

membrance

prey

pray

night blindness

night blindless

vertebrate

vertibrate

Inappropriate use of words

Do not confuse words with similar spellings or pronunciations. For example, the pupil of the eye ‘constricts’, not ‘contracts’, under str ong light.

Under strong light, the pupil ‘contracts’. the pupil ‘constricts’.

c

Omitting titles, headings or units

Remember to give your drawing, graph or table an appropriate title or heading. For calculation, assign a correct unit to the value obtained.


9


4 1

Skills iin a answer ing M MCQs

If you are CERTAIN with the answe r …

 put a ‘

’ beside the question and then

skip the question for checking.

2

If you are UNCERTAIN

with the answer …

 put a ‘?’ beside the question to remind you to pay attention during checking.



look for opposing answers. It is very likely that one of them is the correct answer.



cross out answers that mean basically the same thing. They cannot both be correct.



make a guess instead of leaving the answer blank.


10


5

Skills iin a answer ing essay q questions

There are four major steps to help you answer essay questions.

Step 1

Read the question carefully

While you are reading the question, underline the key points and circle all the command words (e.g. compare, explain, etc.). This can remind you what should be included in your essay.

Sample q question

Q Lipids and proteins are two primary food substances which are essential to life. Compare their functions in the human body.

Step 2

Organize your ideas

Use a mind map, a flow chart or a table to organize your ideas. When it is finished, check if the ideas are coherent and systematic. Cross out any irrelevant information.

Lipids Similar functions

Proteins

- components of the cell membrane - for making hormones - produce ATP - as energy reserves - for protection

Different functions

- transport lipid-soluble vitamins

- as enzymes

- as an insulator - for making myelin sheath

- as antibodies - as haemoglobin - for blood clotting


11


Step 3

Write your essay

Divide your essay into three parts:

1 Introduction

Briefly describe the main theme of your essay. Avoid too much background information.

Lipids and proteins have many functions in the human body. Some of the functions are similar but some are unique to each type of biomolecule. Both lipids and proteins are components of the cell membrane. They are used for making hormones such as steroids (lipids) and insulin (proteins). Both of them act as energy reserves and can be broken down to produce ATP. Lipids and proteins also offer protection to the body. For example, adipose tissues around the internal organs can act as a shock absorber and keratin in nails can provide mechanical protection.

2 Body

Write in paragraphs. Each paragraph should have a

Lipids are a solvent for some vitamins (e.g. vitamins A and D).

main point and the point

They are a good insulator to reduce heat loss from the body.

is explained, elaborated or

Lipids are also used for making myelin sheath around nerve

supported by evidence.

fibres to speed up the transmission of nerve impulses. Some proteins are enzymes. They can catalyse the biochemical reactions in the body. Proteins can act as antibodies which act against the pathogens invading the body. Some proteins are transporters such as the oxygen carrier haemoglobin. Fibrous proteins are involved in blood clotting. They form a network to trap the red blood cells.

3 Conclusion

Lipids and proteins have some similar but also some different

Sum up your points and

functions in the human body. They are both important

restate the main theme.

biomolecules.

Step 4

Check your essay

Check if the essay includes the necessar y information. Make sure there are no spelling mistakes or inappropriate use of words. New Senior Secondary Mastering Biology (Second Edition)

12


6

Skills iin p plotting g gr aphs

Note the following when plotting a graph: 1

Use the x-axis to denote the independent variable and y-axis to denote the dependent variable.

2

Choose a suitable scale and make full use of the graph paper.

3

Label each axis and show the units.

4

Plot each point as a small cross or dot with a sharp pencil.

5

Join the points. If two or more lines are to be drawn on the same graph, draw with different

styles (e.g. solid line versus dotted line) and label them. 6

Give a title to the graph.

Example In an experiment, rats from the same mother were divided into groups A and B. Group A was fed on purified cheese proteins, glucose, starch, fats, minerals and water. Group B was fed on the same food with additional 3 cm3 of milk each day. After 20 days, the diets of t he two groups were e xchanged. The average mass of the two groups of rats from day 0 to day 50 was recorded. The results are presented on the graph below. average mass of rats (g) y-axis is labelled and unit is shown

The change in average mass of rats against time

title is given

90 85

graph paper is fully used with a suitable scale



80











group B



75









70

65







60

55

two curves are drawn with different styles and labelled

group A





symbol to represent the unused part of the scale (045 g). This makes the graph easier to read

50

 

 

 45 

0

5

10

15

20

25

30

35

40

45

50

time (day)

x-axis is labelled and unit is shown New Senior Secondary Mastering Biology (Second Edition)

13


7

Skills iin d dr awing biological d diagr ams

Points to note when drawing biological diagrams 1) Use a sharp HB pencil. Never draw in pen. 2) Draw large diagrams, occupying about two-third of a piece of A4 paper. 3) Draw with smooth single lines. Keep all parts in proportion. 4) Do not shade the diagrams. If you need to show the contrast, you may only use dots.

The denser the dots are, the deeper is the colour. 5) Draw freehand . Do not use a ruler or a pair of compasses. 6) Draw what you see from the specimen. Do not copy from books. 7) Label different parts of the drawing. 

Put the labels by the sides, using labelling lines.



Labelling lines should be straight , horizontal and should not cross each other .

8) Give a title, including the name of the specimen and the power of magnification . 9) State how the section is cut if you are drawing a cut surface of a specimen, such as

longitudinal section ( L.S.) or transverse section (T.S.). 10) State the direction of view if you are drawing a whole specimen, such as dorsal , ventral or lateral view.

The diagram below is poorly drawn. Can you point out the mistakes?


14


There are two kinds of microscopic drawings: 1

Low-power diagrams

a

They show the distribution and proportion of different tissues.

b

Only outlines of structures are drawn. No need to draw individual cells .

For example:

Dicotyledonous plant root (T.S.) (×10)

2

High-power diagrams

a

They show the features of different types of cells.

b

Draw individual cells.

For example:

Vascular tissue in dicotyledonous plant root (T.S.) (×400)


15


8

Skills iin s studying b biology

Studying biology can be easy if you understand the biological concepts instead of memorizing them by rote. Knowing some basic techniques can help you learn biology more effectively.

1

How to remember the spellings of biological terms more easily?

a

By understanding prefixes and suffixes

Many biological terms are built up on Greek or Latin prefixes ( 字首) and suffixes (字尾). By dissecting the biological terms into discrete units and knowing the meanings of the prefixes and suffixes, you will remember their meanings and spellings more easil y. For example: Prefix

Meaning

Example

an-

lacking, without

anaerobic (缺氧呼吸), anaemia (貧血)

anti-

against

antigen (抗原), anti body (抗體), anticodon (反密碼子)

auto-

self

autotroph (自養生物), autoimmune disease ( 自身免疫病), autonomic nervous system (自主神經系統)

bi-

two

biceps (二頭肌), bicuspid valve (二尖瓣), binary fission (二分裂)

di-

two

disaccharide (雙糖), dicot (雙子葉植物), dihybrid (雙基因雜種)

endo-

within

endocrine gland (內分泌腺), endolymph (內淋巴)

exo-

outside

exocrine gland (外分泌腺 ), exoskeleton (外骨骼)

haem-

blood

haemoglobin (血紅蛋白), haemolysis (溶血)

hyper-

above

hypertonic (高滲), hypertension (高血壓)

hypo-

below

hypotonic (低滲), hypothermia (體温過低 )

mono-

one

monosaccharide (單糖), monocot (單子葉植物 ), monoculture (單種栽培)

photo-

light

photosynthesis (光合作用), phototropism (向光性), photolysis (光解)

tri-

three

triceps (三頭肌), tricuspid valve (三尖瓣), triglyceride (甘油三酯)


16


Suffix

b

Meaning

Example

-ase

enzyme

amyl ase (澱粉

), invertase (轉化

-cide

killing agent

fungicide (殺真菌劑), herbicide (除草劑), pesticide (殺蟲劑)

-lysis

breaking down

glycolysis (糖酵解), hydrolysis (水解), photolysis (光解)

-plast

living granule

chloroplast (葉綠體), protoplast (原生質體)

-trophic

feeding

autotrophic nutrition (自養營養), heterotrophic nutrition (異養營養 )

), lipase (

)

By pronouncing words correctly

Marking down each syllable ( 音節) of a word with slashes is very helpful for memorizing the spelling. For example: accommodation

ac / com / mo / da / tion

assimilation

as / si / mi / la / tion

epididymis

e / pi / di / dy / mis

homeostasis

ho / me / o / sta / sis

metabolism

me / ta / bo / li / sm

Bear in mind that this is only a way for you to remember the spellings of the words, but not a way for you to acquire the correct pronunciations.

c

By distinguishing words with similar spellings

Make sure you are able to distinguish words with similar spellings. For example: amino

amnion

afferent

efferent

cerebrum

vs

cerebellum

glycogen

glucagon

ovule

ovary

vertebrate

vertebra


17


2

How to remember biological concepts more easily?

a

By drawing flow charts through logical deductions

Start with what the question asks for, ask yourself what comes next. Answer the question you ask. Base on your answer, ask yourself what comes next again. Repeat and you will get the answer for questions requiring detailed explanation. Example: What happens to the cells when a piece of onion epidermis is i mmersed in a hypertonic solution?

Q What is a hypertonic solution?

A A solution with water potential lower than that of the cytoplasm.

Q What happens when they differ in

A Water moves out of the cells through

water potential?

the differentially permeable membrane by osmosis.

Q What happens to the cells when

A The cells shrink.

they lose water?

Q What happens to the cell membrane

A The cell membrane pulls away from

when the cells shrink? b

By using mnemonics (

the cell wall, i.e. plasmolysis occurs. )

It would be easier to remember some facts or concepts if you can make associations between different words. For example:

c

By using cut-off method (

)

Some biological processes are ‘mirror images’. For example:

 inhalation and exhalation  accommodation of the eye to near and distant objects  constriction and dilation of the pupil In each pair, you can focus on only one of the processes. The other process is simply the other way round.


18


Par t III School-based assessment ((SBA)


19


9

About S SBA

The SBA of biology covers the assessment of students’ performances in practical related tasks throughout the S5 and S6 school years. The tasks include laboratory work and fieldwork . Students will be assessed in two ability areas ( A and B) by their teachers.

Ability area A

Ability area B

Focus on …

practical skills

planning and reporting of scientific investigation

Assessment ability

 organizing and performing practical

 identifying the problem to be investigated and formulating a hypothesis, where applicable

work, including the use of suitable apparatus and equipment, and the appropriate skills in carrying out the work

 devising a plan of investigation according to the problem identified

 making accurate observations and

 recording and presenting results in an appropriate form

measurements

 interpreting and discussing results, and drawing appropriate conclusions

The table below summarizes the percentage weighting and the minimum number of assessments required in S5 and S6 for the different areas of the SBA: Subject

Biology

A

B

A

B

8%

12%

4%

6%

S5

1

1

S6

1

1

1

1

Ability area Weighting Minimum number of assessment

Combined Science (Biology)

Details of the SBA can be found at the HKEAA’s website.

 http://www.hkeaa.edu.hk/en/sba/sub_info_sba/ dse_subject.html?5


20


10

Basic e exper imental techniques

A Making a temporary mount Making a temporary mount is the first step to prepare a specimen for microscopic examination. Steps of making a temporary mount are shown below: 1

Place the specimen in the middle of a

2

slide.

3

specimen.

Let the edge of a cover slip touch the

4

mounting medium.

5

Use a pair of forceps to lower the cover slip slowly and cover the specimen.

Soak up excess mounting medium with

6

tissue paper.


Add 1 to 2 drops of water or stain to the

The slide is ready for microscopic examination.

21


B Free-hand sectioning Free-hand sectioning (徒手切片) is the simplest method to prepare a thin section for a temporary mount. Steps of free-hand sectioning are shown below: 1

Moisten both the razor blade and the

2

specimen.

Hold the specimen as shown below. Rest the razor blade on the tip of the forefinger. Adjust the position of the forefinger to control the thickness of the section.

3

Cut the specimen by sliding the razor

4

Put all the sections into a Petri dish of

blade rapidly and smoothly towards

water. Use a paintbrush to select the

yourself. Repeat the steps to prepare a

thinnest section for examination.

number of sections.


22


C Microscopic examination 1

Place the microscope on the bench with

2

Look through the eyepiece. Adjust the

good illumination. Rotate the nosepiece

angle of the mirror to reflect light towards

and select the low-power objective.

the centre of the stage. Skip this step if the microscope has a built-in light source.

3

Adjust the condenser and the

4

Clip a prepared slide onto the stage. Watch

diaphragm until the light is sufficient

the stage from the side and lower the body

and even.

tube by turning the coarse adjustment knob until the objective nearly touches the slide.

5

Look through the eyepiece again.

6

Slowly raise the body tube by turning

Turn the fine adjustment knob until the image is in focus.

the coarse adjustment knob until the image of the specimen becomes clear.


23


D Using a pipette 1

Rinse the pipette with distilled water

2

followed by the liquid to be transferred.

Insert the pipette filler into the pipette. Squeeze the pipette filler. Use another hand to hold the pipette.

3

Insert the pipette into the liquid to be

4

Remove the pipette filler. Cover the mouth of the pipette by your forefinger.

transferred. Release the filler slowly until the pipette is filled to about 2 cm above the graduation mark.

5

Release your finger to control the flow

6

Transfer the liquid to another container.

until the meniscus of the liquid sits on

Release the liquid. Touch the pipette tip

the graduation mark.

against the side of the container to release the last drop of liquid.

conical flask liquid transferred


24


11

Skills iin w wr iting investigation r r epor ts

When you observe something about the natural world that you do not understand, you may carry out investigations and try to find out the answer. How to carry out a scientific investigation is discussed in detail in the textbook ( Bk 1A, Ch 1, p. 7 11 ). After performing the investigation, you should write a report to share what you have done and what you have discovered with other people. Below is an example to show how to write an investigation report.

Investigation Peter bought some bread. He put it on a table but forgot to eat it. After a week, he found some bread mould growing on the bread surface. He wondered if light affected the growth of bread mould on bread. He carried out an investigation of it with the following set-ups.

After a week, Peter put a transparency with a grid on the bread and counted the number of squares with bread mould in both set-ups.

In set-up A, the number of squares with bread mould is 15. In set-up B, the number of squares with bread mould is 10.


25


An investigation report usually includes the following:

1

Date

2

Aim

It gives the aim of the investigation. Example: To find out whether light affects the growth of bread mould o n bread.

3

Introduction

a

Problem to investigate

Example: Does light affect the growth of bread mould on bread? b

Hypothesis

This part states the hypothesis of the investigation and the prediction based on the design of the investigation. It should be noted that hypotheses are NOT needed in investigations which do NOT require the explanation of observations (like Peter ’s investigation). c

Principle behind the design of the investigation

This part includes:



a brief description of the rationale of the design



identification of the independent and dependent variables , and ways of manipulating and measuring the variables

 the controlled variables Example: Independent variable

Controlled variables

Kind of bread, air temperature, humidity, etc.

Variable

Presence of light

Number of squares with bread mould on the bread

Ways of

Keep a slice of bread in a light-proof box and keep another slice of bread in a transparent box

Put a transparency with a grid on the bread and count the number of squares with bread mould

manipulating and measuring the variable



Dependent variable

the critical assumptions made, if any Example: The two slices of bread in the two set-ups are identical.


26


4

Procedure

This is an account of what you have done during the investigation. It should be concise, precise and presented logically.

Points to note when writing Procedure 1) Write in reported speech, i.e. past passive voice . 2) Number the steps, rather than describing all the steps in a single paragraph. 3) State the quantities of the apparatus and the materials used. 4) Use diagrams or tables whenever appropriate. 5) State any precautions to be taken. 6) Do not repeat the details of a step when the step is just repeated with

different kinds / amounts of materials.

5

Results

There are different ways to present the results, e.g. drawing tables, plotting graphs, drawing biological diagrams, etc.

a

Drawing tables

In a table, the data of the independent and dependent variables should be cle arly put side by side for easy comparison. Example: Conditions

Number of squares with bread mould

Without light

15

With light

10

b

Plotting graphs (Refer to p. 13 for the skills in plotting graphs.)

c

Drawing biological diagrams (Refer to p. 14 for the skills in drawing biological diagrams.)


27


6

Discussion

In this part, you should evaluate how valid the investigation is and recognize trends and patterns in the data.

Points to note when writing Discussion 1) State the limitations of the experimental design. 2) Suggest sources of error in the investigation and their influence on the

accuracy of the results obtained. 3) Consider any unusual observations and assess their significance. 4) Give possible explanations for unexpected results. 5) Suggest improvement for further work.

Next time I should repeat the experiment with more bread to increase the reliability of the results.

7

Conclusion

This part includes the conclusion drawn from the findings with regards to the aim of the investigation. Example: Light slows down the growth of bread mould on bread. It is not necessary to give further explanations, which are not tested by the experiment.


28


Below is the investigation report written by Peter. There are many mistakes in the report. Can you point them out?

Name: Peter Chan

Class: 5A

Class no.: 3

Date of investigation: 12 9 2014 



Aim

To study the growth of bread mould on bread under different conditions.

Only the effect of light was studied in the investigation.

Introduction

(a) Problem to investigate Does light affect the growth of bread mould on bread?

Peter ’s investigation does not need an explanation of

(b) Hypothesis Bread mould does not grow in the presence of light. (c) Principle behind the design of the investigation Independent variable: Number of bread mould

observation. Therefore a hypothesis is not required in this case.

1) Variables are wrongly stated.

Dependent variable: Light

2) Controlled variables and assumptions

Procedure

I put a slice of bread into two different boxes. One of the boxes is a light-proof box and the other is a transparent box. I put the set-ups under light. After some time, I recorded the growth of bread mould on the two slices of bread.

should be mentioned.

1) Steps should be numbered. 2) Reported speech should be used. 3) The duration of the experiment should be clearly stated.


29


Results

The following are the results of the experiment:

Conditions

Number of squares with bread mould on the bread

Without light

15 cm

1) The units are wrong. 2) The units, if any, should be put in the

With light

10 cm

heading of the column, not in the boxes.

It is not necessary to 15

draw a graph for this

d a h t i e r b w s e e h r t a u n 10 q s o d f l o u r o e b m d m u a n e r 5 b

0


investigation as the graph does not help analyse the data.

without light

with light

30


HKDSE Exam Guide(English)

Recommend Documents