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育教僑華 莫三第張五第 日十二月八年未己磨复
1980
WAH KIU YAT PO
dry-bulb thermometer should be be bought.
中學會考試題預習專欄
A VET-BULB AND DRY-BULB THERMOMETER
地理
(-)
Dry-bulb thermometer
Mercury
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GEOGRAPHY (1)
The main purpose of this series of exercises is to help you to get a much better result in the Geography Paper of the School Certificate Examination.} Two essay type questions are each time, with suggestive model answers. They aim at supplying supplementary infor- mation as well as providing revision for you. To acquire the optimum bebefit, students are advised to think of the points carefully by themselves first before reading the model answers, The questions are so carefully set that they covering almost every item of the syllabus, not only give you ample information, hut also help you evaluate your ability to observe accurately. interpret systematically and present your ideas logically,
Revisional Questions:
1. If you were given the task
of setting up a school weather station to measure air temperatures, relative humidity and rainfall amounts, what would you buy? How would you set them out? Draw well-labelled diagram to illustrate your answer,
Suggested Answers:
1. a. Air temperatures
To measure air temperature temperatures, the following instruments should be bought: 1) An ordinary mercury
thermometer to measure
current air temperature or the temperature at a particular time.
2) Maximum thermometer to
measure maximum temp. 3) Minimun thermometer to
measure minimum temp. "DIAGRAMS. TO SHOW THE THREE,
TYPES OF THERMOMETERS Mercury thermometer
Marzung int shem
Maximus thermometer with custristian
Contrition, Mercury, Mon 7
"Break in merensy abroad
Stoxicum thermometer with
metal fader
Meranry
Max to
Minimum thermometer
Alsanch
Metal iden
/Min.T
"Metal indives Procedure of Setting Up 1) All the above, instruments
should be housed horizontal- ly in a Stevenson Screen. 2) This is done since shaded
temperatures are required. 3) The Stevenson Screen is a
wooden box whose roof is double boarded with an air space between so that the heating effect of the sun can be minimized.
4) The Jouvred sides allow the
air to move freely go that the air inside the screen has the same characteristics as the air outside.
5) The screen is painted white
to improve insolation,
6) The screen is mounted on a
stand to avoid heat reflect- ing from the ground from influencing the thermometers directly,
7) It should be positioned in
the most open and exposed place with its door opening to the north to prevent the sun from shining into the screen whilst readings are being taken.
The readings should be recorded daily at a fixed time, preferrable in the murning. After recording, the maximum thermometer should be reset by using a magnet (for the one with a metal index) or by shaking vigorously (for that with a constriction) and the niuinum "thermometer should be reset by filling it. gently.
h. Pelative humidity
To measure relative. humidity, a wet-bulb and
Water
Wet-bullo thermometer
Procedure, of Setting Up 1) It should be housed in the
Stevenson Screen, too. 2) The bulb of the wet-bulb
thermometer should be kept moist all the time by covering it with muslin which dips into a container of water.
3) The difference between the
two readings is an indicator of the humidity of the air:
if there is no difference
عبد
the air is saturated
if the difference is large
humidity is low
if the difference is small
humidity is high
-
4) The actual value of relative
humidity is obtained by checking the reading from a book of tables.
c. Amounts of Rainfall
To measure the amount of rainfall, a rain gauge is necessary.
A HAIN GAUGE
Funnel
· Copper cylinder
Glass bottle
・Outer copper case.
Procedure of Setting Up
In setting up the rain gauge, the following points must be noted:
1) It must be put on level
ground.
2) It must be placed in an
exposed position, får away from any objects which might affect the amount of reinfall collected. If the buildings and trees are present, the gauge must be positioned away from then at a distance of at least twice the height of the se objects.
5) It must be sunk in the
ground to prevent it from being blown or knocked over, 4) The top of the funnel must
be 30,8cm (12") above ground-level, to prevent rain nearby splashing into the jar..
2. Below are diagrams showing
information of rainfall in Hong Kong. With the eid of diagram, account for the seasonal and- geographical distributions of rainfall in Hong Kong.
Fig.I RAINFALL DISTRIBUTION
OF HONG KONG
Over 3500
2000-3250m
1760-2000 mean
Muck belum 1150
Fig. II TEMPERATURES & PAINPALI
OF HONG KONG
Temp In
75
גי
10
JEMAMIJAS ORD
Suggested Answers:
We
DO
HỌC
The Seasonal Distribution 01) Rainfall in Hong Kong
From the climatic graph, can see that the rainfall in Hong Kong, with an annual total of about 200 - 2500 mm.,
does not distribute evenly. About 80% of the rain occurs in the summer moutha - from May to Sept. A monthly total of over 250 am in the summer rainy season, is not uncommon. Phile in winter, it is
relatively dry.
The gunmer maximum of rainfall in long long cặn partly be explained by the influence of riongosus. Hang Kong lies in the Asjan monsoonal wind belt, in
報日僑
sunime, a low pressure helt is formed over Mongolia, while a high pressure belt is found over the sea. Ab a result, the wind blow inland from the sea. They are therefore moist and they bring heavy rain to Hong Kong. In winter, the winds blow offshore because the low pressure over Mongolia is by now replaced a high pressure system. Thus the winds that influence fong Kong are quite dry (Fig. A).
FILA THE SUMMER MONSOON -
OF ASIA
INTENSE
Lubr
PRESSURE,
(HORSE LAST
HIGH
DOLD RUM!
LOW
Besides the monsoons, seasonal distribution of
the
rainfall in Hong Kong is also, greatly affected by typhoons. The typhoons, which attack Hong Kong mostly from May to Sept, are always accompanied by torrential rain (Fig. B). Fig.B MAIN TYPHOON TRACKS IN THE WEST PACIFIC OCEAN
Most of the
"formed to the
of Philippines
Furthermore, the high summer temperatures in Hong Kong (with an average around 27°C) are likely to induce rainfall too. When the land surfaces are overbeated, strong vertical air currenta set up. As the air ascends, its temperature i's reduced until condensation takes place and clouds are formed. The water droplets in the clouds will become bigger with further ascert, which means further cooling. In time the water droplets in clouds become too big and heavy to be saturated, rain begins to fall. This type of rain is known as convectional rainfall. Hong Kong, being situated in the tropical latitudes, the convectional rainfall is especially characteristic in summer (Fig. C).
Fig.C FORMATION OF
CONVECTIONAL RAINFALL
DESCENDING
Cumulo-nimbu
clouds.
**A RAIN
Land swfdce, benkpl.
The Geographical
level of
condensation
Distribution of Rainfall
in Hong Kong ›
Fig. II is the annual rainfall map. of Hong Kong. The map shows that the areas with maximum rainfall (over 2200me) coincide with high- lend areas, e.g. Tai No Shan region and Lantao Shan region.
The areas with the lowest amount of rainfall (below 1800mm) lies on the west,. fig. the northwest lowland around Deep Bay, the southwest of Lantao Island and the Tsing Y Island. Such a grographic distribution indicates an orographic effect. This is because, as mentioned above, must of the rain în Hong Kong is brought hy onshore monsoons which blow mainly in an easterly direction from the sea. As the moisture-Jaden winds meet the mountains, they will be forced to rise. They are then cooled, conden-' sation thus occurs and clouds are formed. Being subjected to much the same process as those in the rising air
三期星
currents
日十月十年九七九一番公佈八十六國民華中
as heated, water droplets fall down at last. Thus the mountain regions, especially the east-facing slopes in Hong Kong, have more rain because of this orographic effect. By the time the winds reach the lowlying western part, they are depleted of moisture. As they descent the leewurd slopes, they are warmed by compres- sion. Consequently, there is little rain and these areas are referred to as rain shadow areas (Fig 1). Pig.D THE FORMATION OF
OPOGRHIC (relief) RAIN
As air ascends.
it becomes cooter!
and saturated
Rises
Windward
Mountain
mass
生物
As a descensates, it comprossed land becomes warmer ~ R.H. fuils
Leeward slope
RAIN
SHADOW
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BIOLOGY (1)
Unit 1: Nutrition
Plant Nutrition
1. The rate of evolution of gas
bubbles from a plant (hydrilla) in water and in dilute sodium bicarbonate Solution with a light source at varying distances was measured. The following diagram shows the apparatus used.
Gas
Plant
Lamp
Distance
The results are shown in the following table.
Distance (cm)
10 20 30 40
30 26 16 8
in water No. of in (bubbles sodium 120|80|50|30
per min. bicarbo-
nate sol.
(a) What physiological process
of the plant is being investigated?
s collected
(b)(1) Name the gas.
in the test-tube.
(2) How would you test for the gas?
(c) What is the purpose of varying the distance between the plant and the light, source?
¿
(d) Plot'the results of this
experiment on the graph paper provided. (e) Describe and explain the
general relationship between the rate of gas bubble evolution and the distance of the light source. (f) Describe and explain the
effect of sodium bicarbonate solution on the rate of gas bubble evolution.
(g) Using a similar set of apparatus, how can you prove light is essential for the evolution of gas bubbles?
2. After a green plant has been
placed in dark for 2 days, leaves are picked and treated for 2 hours at 20°C as in the experiment illustrated below.
Kept en ginj
Water
Lea! 8
kept in dark
Water
Lear C Kept in dark
5% glucose solution
At the end of 24 hours the leaves are tested for starch. The results show that starch is present in leaves A. and C but absent in B.
(a) What is the purpose of
placing the plant in dark for 2 days before the experiment.
(b) State a major force that
causes the water and glucose solution to rise in the petiole and enter the mesophyll of the leaves?. (c) Explain why starch is
present in A.
(d) What conclusion can be
drawn from the results for.
(1) leaf A and leaf B?
(2) leaf B and leaf C?
(e) Further experiments show
that leaf C would not
produce starch in the
absence of oxygen. How would you explain this observation?
ANSWERS:
1. (a) Photosynthesis.
(b)(1) Oxygen
(2) Insert a glowing splint
into the test-tube. If the gas relights a. glowing splint, it is oxygen.
(c) The purpose is to vary the
light intensity.
(d)
No. of bubbles/ min.
120
80
Sodium bicarbonate
blution
10 20 30 40
Distance fera)
(e) The rate of gas bubble
evolution decreases as the distance of light source increases. It is because light provides the plant energy necessary for photosynthesis. The rate of photosynthesis is therefore decreases as the energy input decreases (i.e. the distance of light source increases).
(f) It causes an increase in
the rate of bubble evolution. It is because the solution provides the plant a rich source of carbon dioxide which is an essential raw material for photosynthesis.
(g) The apparatus can be
covered with a piece of black cloth to cut out the illumination of light on the plant. Then examine whether any oxygen is collected a few hours later.
2. (a) The purpose is to
destarch the leaves so that distinct results can be obtained if starch is formed; during the experiment. (b) The transpiration pull of
the leaves.
(c) Photosynthesis has taken
place in leaf A, (d)(1) Light is required for photosynthesis.
(2) Leaf can convert
glucose into starch.
The conversión does not require light.
(e) It seems that energy is
required for the conversion, of glucose into starch. Leaf C could not produce starch in the absence of oxygen because no respiration took place to produce energy.