Chp 1 Suggested Answer

Unit 1 Introducing science

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1.1 Science and us

I True or false questions (p.1) (1 m each) 1 T 2 F 3 F 4 T 5 F 6 F

II Fill in the blanks (p.1) (2 m each) 1 science

2 Scientists, observations, experiments, conclusion 3 discovery

4 invention

III Multiple-choice questions (p.2) (1 m each) 1 D 2 D 3 A 4 D 5 C IV Matching (p.3) (5 m) a: ii b: v c: iv d: i e: iii V Question (p.3) a Alexander Fleming. (1 m) This is a discovery. (1 m) b He found a region without bacteria around the mould. (1 m) c Howard Florey and Ernest Chain. (2 m) This is an invention. (1 m)

d Scientists make observations carefully./Scientists ask questions about their observations./Scientists suggest possible answers to the questions./Scientists collect evidence for supporting their answers./Scientists draw a conclusion which answers their question./Scientists work in a team and study other’s work. (Any two of the above) (2 m)

1.2 Working in the laboratory

I True or false questions (p.4) (1 m each) 1 F

2 T 3 F 4 F 5 F

II Fill in the blanks (p.4) (2 m each) 1 laboratory

2 equipment 3 apparatus 4 fire escape route 5 laboratory rules 6 safety goggles

7 hazard warning labels 8 fire-fighting equipment

III Matching (p.5) (5 m)

a: iii b: iv c: i d: v e: ii

IV Multiple-choice questions (p.5) (1 mark each) 1 B 2 D 3 D 4 C 5 B 6 B 7 D

V Questions (p.7)

1 a test tube / boiling tube (1 m)

(1 m)

to hold liquid or small solids (1 m)

b stand and clamp (1 m)

(1 m) to fix the position of apparatus (1 m)

c beaker (1 m)

(1 m) to hold liquids or solids (1 m)

d Bunsen burner (1 m)

(1 m)

to heat substances (1 m)

e tripod (1 m)

(1 m) to support the wire gauze (1 m)

2 a explosive (1 m) b corrosive (1 m) c flammable (1 m) d harmful (1 m) e toxic (1 m) 3 a Bunsen burner (1 m)

b test tube brush (1 m)

c wire gauze (1 m) d evaporating dish (1 m) e insulating mat (1 m) f tongs (1 m) 4 a _{(4 m)} b A: Wear safety goggles when heating substance./Do not eat or drink in the

laboratory. (1 m)

B: Never play or run in the laboratory. (1 m) C: Tie up long hair when doing experiment. (1 m) D: Keep all exits and passages clear. (1 m) 5 a i Wash the affected area with running water. (1 m) ii Clean and dress the cut. (1 m) iii Wash the affected area with running water. (1 m) iv Wash the eye using an eye wash bottle. (1 m) b Report the accident to the teacher at once. (1 m)

1.3 Basic skills in doing experiments

I True or false questions (p.10) (1 m each) 1 F 2 T 3 F 4 F 5 T 6 T

II Fill in the blanks (p.10) (2 m each) 1 striking back

2 temperature, degree Celsius, thermometer 3 stop-watch

4 volume, cubic 5 meniscus 6 weight

III Multiple-choice questions (p.11) (1 mark each) 1 B 2 A 3 B 4 C 5 B 6 D 7 B 8 B IV Questions (p.13) 1 a chimney (1 m) b collar (1 m) c base (1 m) d air hole (1 m) e rubber tubing (1 m) f gas tap (1 m) 2 ii
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iii (2 m)

3 The hand is higher than the top of the chimney. The fingers may be burnt by the

Bunsen flame. (1 m)

Air hole is closed Air hole is open

yellow (1 m) blue (1 m) irregular (1 m) regular (1 m) luminous (1 m) non-luminous (1 m) quiet (1 m) noisy (1 m) 4 lower (1 m) higher (1 m) 5 B (1 m)

6 Make sure the room is well-ventilated./Do not touch the hot chimney when the burner is in use or immediately after use./Wear safety goggles./Tie back long hair and fasten school ties. (Any two; accept other reasonable answers.) (2 m) 7 Volume = length × breath × height (1 m)

= 12 × 12 × 12

= 1728 cm3 (1 m)

8 Top pan balance, spring balance, triple beam balance, lever balance, electronic

balance (any three) (3 m)

9 a i 47 mL (1 m) ii 89 mL (1 m) iii 56 cm3 (1 m) b i 5 min 19 s (1 m) ii 12 min 38 s (1 m) iii 1 min 16 100 3 s (1 m) c i 16℃ (1 m) ii 36.5℃ (1 m) iii 42.1℃ (1 m)

1.4 Conducting a scientific investigation

I Fill in blanks (p.16) (2 m each)

1 observations; Setting a question; hypothesis; experiments, recording results; Analysing results, drawing a conclusion

II Multiple-choice questions (p.16) (1 m each) 1 A 2 C 3 D 4 C 5 A III Questions (p.18) 1 a A: iii B: v C: i D: iv E: ii (5 m)

Variable Dose it need to keep the same?

Dose it need to change? Weight of sugar _{ (1 m)}

Volume of water  (1 m)

Form of sugar used  (1 m)

Temperature of water _{ (1 m)} b

Extent of stirring the water _{ (1 m)}

2 a Test 1: unfair (1 m)

the volumes of water are not the same. (1 m)

Test 2: unfair (1 m)

the lengths of the strips in water are not the same. (1 m)

Test 3: unfair (1 m)

the temperatures of water are not the same. (1 m) b

same volume of water (1 m) same length of strips in water (1 m) same water temperature (1 m)

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I True of false questions (p.20) (1 m each) 1 F 2 T 3 F 4 F 5 T 6 T 7 F 8 T

II Multiple-choice questions (p.20) (1 m each) 1 C 2 B 3 B 4 A 5 C 6 B 7 D 8 D III Questions (p.22)

1 Underlined word Correct answer a apparatus equipment b test tube holder tongs

c metre rule measuring tape

d controlled independent (8 m)

2 a A first aid box (1 m)

B thermometer (1 m)

C electric socket (1 m)

D test tube rack (1 m)

E reagent bottle (1 m)

F tripod (1 m)

G fire extinguisher (1 m) H triple beam balance (1 m)

I safety goggles (1 m)

b G (1 m) c Eat, drink, play or run in the laboratory. (Or other reasonable answers,

see p.21 of Student’s Book) (1 m) Measurement Suitable unit

Length of a test tube (given)

Height of the Statue of Liberty in USA metre (m) (2 m) Weight of a chocolate bean gram (g) (2 m) 3

Volume of a can of soft drink millilitre (mL) or cubic

centimetre (cm3) (2 m)

4

(0.5 mark each for correct sectional drawing of each apparatus, 1.5 marks for the

correct set-up) (5 m)

5 a Measuring cylinder (1 m)

b Volume of cork stopper = 290 – 255 (1 m) = 35 cm3 (1 m) c So that the whole cork stopper can be put into water. (1 m)

6 a Stop-watch (1 m)

b Average time = (5.4 + 5.8 + 5.6)/3 (1 m) = 5.6 s (1 m) c Repeating the measurement can give more accurate results. (1 m) 7 a If the water temperature is higher, less stain remains on the cloth. (1 m)

b water temperature (1 m)

c amount of washing powder in each beaker (1 m)

volume of water (1 m)

(or other reasonable answers)

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It is heat-resistant and can contain a larger volume of liquid than

other apparatus. (1 m)

ii W (0.5 m)

It allows us to observe the result more clearly. (1 m)

iii Y (0.5 m)

It can give a more accurate reading than other apparatus. (1 m)

iv X (0.5 m)

It is designed for shaking and it can contain a larger volume of liquid than other apparatus. (1 m)

2 a An invention (1 m)

b i The earliest light bulbs could only glow for a short period of time. (1 m) ii Can the material of the filament change the time of glow? (1 m) iii Filaments made of some materials can glow longer than others. (1 m) iv Preparing filaments of different materials, and measuring the time that

they can glow. (1 m)

v Filaments of different materials glow for different periods of time, and the filament made of carbon can glow for the longest time. (1 m) c i Material of the filament (1 m)

ii Time of glow (1 m)

iii Length (1 m)

and thickness of filament. (1 m) (Accept other reasonable answers.)