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)
test tube brush wire gauze evaporating dish insulating mat
(1 m) (1 m) (1 m) (1 m)
f
tongs
(1 m)
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. 5
a i ii iii iv
Wash the affected area with running water. Clean and dress the cut. Wash the affected area with running water. Wash the eye using an eye wash bottle.
The hand is higher than the top of the chimney. The fingers may be burnt by the Bunsen flame. (1 m)
4
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)
lower
(1 m)
higher
(1 m)
5 6
B (1 m) 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)
Z (0.5 m) It is heat-resistant and can contain a larger volume of liquid than other apparatus.
(1 m)
ii W It allows us to observe the result more clearly.
(0.5 m) (1 m)
iii Y It can give a more accurate reading than other apparatus.
(0.5 m) (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 b i The earliest light bulbs could only glow for a short period of time. ii Can the material of the filament change the time of glow? iii Filaments made of some materials can glow longer than others.
(1 m) (1 m) (1 m) (1 m)
iv Preparing filaments of different materials, and measuring the time that they can glow. (1 m) v c
Filaments of different materials glow for different periods of time, and the filament made of carbon can glow for the longest time. (1 m)
i Material of the filament ii Time of glow iii Length and thickness of filament. (Accept other reasonable answers.)
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