Essay Questions Ibank[1]

Science SPM – Paper 2 (Essay question) 1

SCIENCE SPMSCIENCE SPMNAME :CLASS :

CONTENTSFORM 4CHAPTER 1 SCIENTIFIC INVESTIGATIONCHAPTER 2 BODY COORDINATIONCHAPTER 3 HEREDITY AND VARIATIONCHAPTER 4 MATTER AND SUBSTANCESCHAPTER 5 ENERGY AND CHEMICAL CHANGESCHAPTER 6 NUCLEAR ENERGYCHAPTER 7 LIGHT, COLOUR AND SIGHTCHAPTER 8 CHEMICALS IN INDUSTRY

FORM 5CHAPTER 1 MICROORGANISMS & THEIR EFFECTS

ON LIVING THINGSCHAPTER 2 NUTRITIONCHAPTER 3 PRESERVATION & CONSERVATION OF

THE ENVIRONMENTCHAPTER 4 CARBON COMPOUNDCHAPTER 5 MOTIONCHAPTER 6 FOOD TECHNOLOGY AND PRODUCTIONCHAPTER 7 SYNTHETIC MATERIALS IN INDUSTRYCHAPTER 8 ELECTRONICS & INFORMATION

& COMMUNICATION TECHNOLOGY (ICT)

YL KONG @SMKSARATOK2008


ESSAY QUESTIONSCHAPTER 1 : SCIENTIFIC INVESTIGATION

1 The length of a spring is affected by the weight of the loadYL KONG @SMKSARATOK2008


(a) Based on the statement above, write one suitable hypothesis.[1 mark]

(b) Using a spring, few loads and other apparatus, describe an experiment to test your hypothesis in (a) based on the following criteria;

· Aim of the experiment [1 mark]· Identification of variables [2 marks]· List of apparatus and materials [1 mark]· Procedure [3 marks]· Tabulation of data [1 mark]· Conclusion [1 mark]

ANSWER

(a) Hypothesis: The heavier the weight of the load, the longer the length of the spring.(b) Aim : To study the relationship between the length of a spring and the weight of the load.

Variables that are:(i) manipulated: the weight of the load (ii) responding: length of the spring(iii) constant: the same spring / diameter of the spring.Apparatus: spring, five different weight loads, retort stand, rulerProcedure:1. The spring is hung on a retort stand.2. The length of a spring is measured.3. A 0.2 N load is hung to the end of the spring and the length is measured.4. Step 3 is repeated by increasing the load 0.2N each time until 1.0N.5. The results are recorded in the table below

Tabulation of data

Weight of the load, W/N Length of spring, l / cm0

0.20.40.60.81.0

Conclusion The length of the spring increases as the weight of the load increases. Hypothesis is acceptable.

2 (a) State the importance of a scientific investigation method in acquiring scientific knowledge.

[4 marks]



(b) Zainal wants to carry out a scientific investigation to measure the response time of his friend. Explain the steps he has thought ahead before he can start the experiment.Your answer should include the following;

· Identify the problem [1 mark]· Operational definition of response time and other variables. [2 marks]· List of apparatus [1 mark]· Steps in the method used [2 marks]

ANSWER

(a) · It is a systematic and complete way to acquire scientific knowledge· It enables students to learn the right way of acquiring scientific knowledge· It inculcates the right values and attitudes in students· It helps to minimise misconception or prejudice in an experiment.

(b) Problem statement: How is the scientific investigation method used to determine the response time of a person.Operational definition of response time: the mark at the rule caught by the finger.Apparatus: meter ruleManipulated variable : different studentConstant vriable : the same rulerSteps in the method used:1. A meter rule is held with 0 facing down and put in between the friend's thumb and second

finger at the zero position.2. The meter rule is suddenly dropped and the friend is required to catch the rule with the thumb

and second finger.

3 (a) State the items in a correct sequence when writing out a report.[4 marks]



(b)

Study the information above and construct the concept of scientific investigation.Your answer should be based on the following steps:· Identify the common characteristics· Develop the initial concept in the scientific investigation method· Give two other examples to the concept· Explain the actual concept

[6 marks]ANSWER

(a) Aim, Problem statement, Hypothesis, Variables, Apparatus and materials, Procedure, Result, Discussion, Conclusion.(b)Common characteristic: Scientific attitudes and noble values are practised in scientific investigation. Initial concept: Scientific attitudes and noble values should be absorbed during learning and teaching science.Two other examples: Systematic / Rational thinking / Fair and impartial / Hardworking and perservering.Actual concept: Practising scientific attitudes and noble values will lead to a better understanding and interpretation of a scientific investigation.

CHAPTER 2 : BODY COORDINATION

4 The figure below shows two patterns of block arrangement.



Study the following statement.

A man who has seen the arrangement of wooden blocks as shown in the figure above can rearrange it blind-folded.

(a) Suggest a hypothesis to investigate the above statement.[1 mark]

Using six identical wooden blocks of similar size, describe an experiment to test your hypothesis in (a) based on the following criteria;· Aim of the experiment · Identification of apparatus· Procedure· Tabulation of data · Conclusion

[9 marks]ANSWER

(a) Kinaesthesia allows a man to estimate the position of objects without looking at the objects.(b) Aim: To study the role of kinaesthesia in estimating the position of objectsApparatus: six identical wooden blocks, black scarfProcedurea. Let a friend look at the arrangement of block shown as in the figure in the question.b. Blind-fold the friend using a black scarfc. The wooden blocks are scattered.d. Ask the friend to arrange the wooden blocks according to the figure in the question.e. The observation is recordedf. Repeat with 3 other friends

Tabulation of data:Name of friend Is the arrangement correct? (Yes/No)1.2.3.4.

Conclusion:Kinaesthesia helps the blind-folded student to arrange the wooden blocks in the correct pattern.

5 (a) State the differences between voluntary action and involuntary action.[4 marks]

(b) A patient is not able to walk, hold things or wake up by himself, but he is still able to talk and YL KONG @SMKSARATOK2008


remember his siblings after an accident.Explain what has gone wrong with his brain.Your explanation should include the following:· Part of the brain which is injured · Part of the brain is functioning · How those parts of the brain affect the patients activities.

[6 marks]

ANSWER

(a)Voluntary action Involuntary ActionThe response is not automatic The response is automaticResponse controlled by desire Response is not controlled by desireThe speed of reaction is slow The speed of reaction is fast and

quickImpulse flows through the cerebrum

Impulse flows through the medulla oblongata

There is awareness of the action There is no awareness of the action(Any 4)

(b)- Part of the brain that is injured is the cerebellum.- Cerebellum controls the body balance and all the body movements such as walking and holding things.- Part of the brain that is functioning is the cerebrum and medulla oblongata- Cerebrum controls all voluntary action; somehow when the cerebellum is injured, loses its controlling and coordinating muscular activities- Cerebrum acts as a centre for mental activities such as speed and memory- Medulla oblongata controls all the basic and important life activities like breathing and heartbeat.

6 (a) Describe how the side-effects of excessive alcohol consumption affect the driving skill of a human.

[4 marks]



(b) The figure below shows several effects on human health of the habit of excesive consumption of alcohol.

Study the above effects. Describe how excessive consumption of alcohol may cause the above effects on human health.Your answer should be based on the following:· Identify the information· Identify the common characteristics· Relate the common characteristics of the effect on human health · Give an example of another effect on human health and a non-health example on

humans.· State the effect of excessive consumption of alcohol

[6 marks]ANSWER

(a) - Alcohol causes a poor judgment of distance- Alcohol causes a double vision- Alcohol slows down the nervous system as it affects body coordination and movement - Alcohol causes a person to lose self-control(b) - Alcohol abuse may cause blockages in blood capillaries, resulting in less oxygen being transported to the brain, causing the brain size to shrink - Alcohol abuse causes heart muscle to deteriorate, thus leading to heart disease- Kidney tends to reabsorb less water, leading to dehydration- Excessive consumption of alcohol causes great damage to the human body. - Example of excessive alcohol consumption to human health is cirrhosis / gastritis / ulcers - Non-example of excessive alcohol consumption to human health is social problem / accident - Excessive consumption of alcohol may lead to addiction which causes health problem to the drinker, social problems to others and traffic accidents.

CHAPTER 3: HEREDITY AND VARIATION

7 Study the following statement.



There are two different shapes in the ear lobes of the students in a class.

(a) Using the student population in a class, suggest a hypothesis to study the above statement.[1 mark]

(b) Describe an experiment in your classroom to test your hypothesis according to the following criteria.

· Aim of experiment [1 mark]· Identification of variables [2 marks]· List of apparatus and materials [1 mark]· Procedure [2 marks]· Tabulation [1 mark]· Analysis of data [1 mark]· Conclusion [1 mark]

ANSWER

(a) The shape of the ear lobe is a discontinuous variation which can be clearly classified into the free ear lobe or the attached ear lobe. (b) Aim: To study the shape of the ear lobe among the pupils. Variables that are(i) manipulated: different students in the class room(ii) responding: type of ear lobe(iii) constant: normal humansList of apparatus and materials: number of students in the class, figure of the shape of ear lobeProcedure:3. Group the pupils in pairs.4. Based on the figure of the shape of ear lobe, determine the shape of the ear of their friend.5. Record the results in the table below.

Tabulation:Shape of ear lobe Attached ear lobe Free ear lobeTallying

Number of occurrences

Analysis of data: Draw a bar chart of number of occurrences vs shape of ear lobe.



Conclusion: The shape of ear lobe is discontinuous variation.

9

(a) The figures (a) and (b) show the formation of twins. Name the types of twins and state three differences about the types of twins

[4 marks]

(b) A normal married couple wishes to have a baby boy. Explain the mechanism of sex determination of a baby.Your answer should includes the following· Identify which gamete could determine the sex of a baby· Clarify the chromosomes which determine baby boy· Draw the genetic chart for the sex determination in the baby· The percentage of getting a baby boy for the couple.

[6 marks]



ANSWER(a)

Figure (a) Figure (b)Identical twins Non-identical twinsOne single ovum is fertilized by one sperm to form one zygote, then divides into two zygotes

Two ova are fertilized by two sperms, forming two zygotes

Two foetuses sharing one placenta Two separate placentas, one for each foetusBoth have similar genetic content Both have different genetic content

(b) The father's sperms determine the sex of a baby.A baby which inherits a Y chromosome from its father, will be a boy. If it inherits a X chromosome from its father, it will be a girl.

The percentage of getting a boy is 50%.

10 (a) Define mutation and mutagen. Describe two factors that cause mutation.

[4 marks](b) The figure below shows mutation which happens in the body cell of human.

Study the abnormalities caused by mutation above. Explain how you can built a concept based on the information in the figure above.Your explanation of the concept should include the following:· Identify two common characteristics [2 marks]· Develop initial concept [1 mark]· Give another example and a non-example in relation to the concept [2 marks]· Explain the actual concept [2 mark]



ANSWER

(a) - Mutation is a change in the genes or chromosomes that can alter the original traits of organisms.- Mutagen is a substance or radiation that can induce or cause mutation.- Nuclear radiation such as alpha, beta, gamma and harmful ray can penetrate the nucleus of a cell and change the structure of the genes and chromosomes.- Chemicals such as mustard gas, benzene and dioxins can react with DNA in the chromosomes

(b) Common characteristics- Additional or deletion of one chromosomes in the human body cell compare to the normal human body cell. - The difference in the number of chromosomes occur during meiosis to produce gametes with either more or less the number of chromosomes Initial concept- The change of the number or the structure of chromosomes is called chromosome mutation.Other example - Klinefelter's syndrome Non-example- Albinism / colour blindness / sickle cell anaemiaActual concept

- Chromosome mutation is the result of the changes in the number or structure of chromosomes

11 (a) State two advantages and two disadvantages of genetic research to humans.[4 marks]

(b) A local Subang 6 papaya fruit is big but is less favourable to consumers.Explain how MARDI solves the problem in increasing the consumption of local fruit.Your answer should include the following:

· Identify the problem [1 mark]· Clarification of the traits of local papaya fruit and imported variety. [2 marks]· Name the solving method. [2 marks]· State the favourable trait of the product. [1 mark]

ANSWER(a) Advantages :1. genetic research has produced better medicines and vaccines for medical treatment.2. genetic research has improved the quality of crops and livestock.Disadvantages:1. genetic research may lead to extinction of species as new varieties replace them.2. genetically modified food may be harmful to human health.(b) - The local papaya is less favourable to the consumer.- The traits of a local papaya are its big size, less sweet taste and has average thick flesh.- The traits of an imported variety are its fragrant smell, sweetness and small size when planted locally- Selective breeding is done between Local Subang 6 papaya and Hawaiian Sunrise Solo papaya to produce a new variety named Eksotika Malaysia.- Eksotika Malaysia is sweet, smells fragrant with thick fresh and is average in size.



CHAPTER 4: MATTER AND SUBSTANCES

12 The melting point of an ionic substance is higher than a molecular substance.You are given lead bromide and naphthalene.Carry out an experiment to prove the statement. Your answer should include the following:

(a) Aim of experiment. [1 mark](b) Hypothesis of experiment. [1 mark](c) List all variables. [3 marks](d) Procedure. [3 marks](e) Data tabulation. [2 marks]

ANSWER

(a) To show that the melting point of lead bromide is higher than the melting point of naphthalene.(b) The melting point of an ionic substance is higher than a molecular substance.(c) Manipulated variable : Lead bromide and naphthalene. Responding variable : Melting point Constant variable : Mass of substance heated.(d)

20 g of lead bromide is placed in a crucible. A thermometer is placed in the substance. The substance is heated. The temperature at which the substance melted is recorded The experiment is repeated by using 20 g of naphthalene.(e)

Substance Lead bromide NaphthaleneMelting point (oC) Higher than 100oC Lower than 100oC



13 An ionic substance is an electrolyte whereas a molecular substance is not.You are given sodium chloride and sugar.Carry out an experiment to prove the above statement.Your answer should include the following:

(a) Aim of experiment. [1 mark](b) List all variables. [3 marks](c) Procedure. [2 marks](d) Data tabulation. [2 marks](e) Explanation of the result of experiment. [2 marks]

ANSWER

(a) To show that an ionic substance conducts electricity whereas a molecular substance does not.(b) Manipulated variable : Sodium chloride aqueous solution and sugar solution. Responding variable : Lighting of bulb. Constant variable : Mass of substance dissolved in 50 cm3 of water.(c)

10 gram of sodium chloride and 10 g of sugar are dissolved in 50 cm3 of water in separate beakers. Two carbon electrodes are immersed into each of the solution. The electrodes are connected to a dry cell. The lighting of the bulb is noted.

(d) Solution Sodium chloride SugarObservation Bulb lights up. Bulb does not light up

(e) The sodium chloride solution consists of free moving ions that carry charges. Thus it conducts electricity. The sugar solution consists of molecules which does not carry charges. Thus the solution is a non-electrolyte.



13 A sample of sodium chloride salt is mixed with sand. Describe how the salt can be separated and purified from the mixture.

[10 marks]

ANSWER

The following procedure is carried out:(a) About 100 cm3 of water is poured into a beaker. The water is heated. (1) The sand and salt mixture is added and stirred. The sodium chloride dissolves in the water whereas the sand does not. (1)(b) The solution is then filtered. (1) The insoluble sand is collected as residue on the filter paper whereas the filtrate contains sodium chloride salt. (1)(c) The filtrate is poured into an evaporating dish. The solution is heated to evaporate the water until the solution becomes saturated. (1)(d) The saturated solution is allowed to cool. (1) The sodium chloride salt will crystallized out. (1)(e) The saturated solution is then filtered. The solid salt crystal is trapped as residue on the filter paper. (1)(f) The salt is rinsed with distilled water. (1)(g) The crystal is then transferred to a piece of dry filter paper and then pressed to absorb the water. (1)



CHAPTER 5 : ENERGY AND CHEMICAL CHANGE

14 Sodium is more reactive than carbon. Describe how the metal sodium can be extracted from sodium chloride. Your answer should include the following:

(a) Identifying the problem. [1 mark](b) Name the principle used. [1 mark](c) An apparatus which shows the apparatus set-up. [2 marks](d) Procedure. [2 marks](e) Observations. [2 marks](f) Write word equations for reactions taking place. [2 marks]

ANSWER

(a) How is sodium metal extracted from sodium chloride salt?(b) Sodium is extracted from the electrolysis of molten sodium chloride.(c)

(d) Sodium chloride is heated until it melts. Electricity is passed through the molten sodium chloride using carbon as electrodes.(e) At anode : Greenish chlorine gas is released. At cathode : Silver sodium metal is formed.(f) At anode : Chloride ion chlorine gas + electron At cathode : Sodium ion + electron sodium metal

15 “Chemical energy can be converted into electrical energy”. Describe an experiment to prove the above statement.Your answer should include the following:

(a) Aim of experiment. [1 mark](b) Name the principle used. [2 marks](c) An apparatus which shows the apparatus set-up. [2 marks](d) Procedure. [2 marks](e) Observation. [1 mark](f) Write word equations for reactions taking place. [2 marks]



ANSWER

(a) To show that chemical energy can be converted into electrical energy.(b) When two different metal electrodes are immersed into an electrolyte, electrical energy is produced.(c)

(d) Zinc and copper electrode are immersed into copper sulphate solution. The two electrodes are connected with a connecting wire to a galvanometer.(e) The needle of the galvanometer deflects.(f) At zinc electrode: Zinc zinc ion + electron At copper electrode: Copper ion + electron copper



16 Describe an experiment to show that the reactivity of magnesium > zinc > lead > copper.Your answer should include the following:

(a) Aim of experiment. [1 mark](b) Name the principle used. [1 mark](c) An apparatus which shows the apparatus set-up. [2 marks](d) Procedure. [4 marks](e) Tabulation of results. [2 marks]

ANSWER

(a) To determine the relative reactivity of magnesium, zinc, lead and copper.(b) The more reactive the metal the brighter is the reaction of the metal with oxygen.(c)

(d) Potassium permanganate(VII) is placed into a boiling tube. Some glass wool is then pushed into the tube. Some magnesium powder is added into a porcelain boat and then placed in the tube. The magnesium powder is heated strongly followed by heating the potassium permanganate(VII). The reactivity of the reaction is recorded. Experiment is repeated by replacing magnesium powder with other metal powders.(e)

Metal ObservationMagnesium Burns very brightly

Zinc Burns brightlyLead Glows brightly

Copper Glows dimly



CHAPTER 6 : NUCLEAR ENERGY

17 (a) Describe how electricity is generated in a nuclear power station.[6 marks]

(b) Give two advantages and two disadvantages of using radioisotopes to generate electricity.[4 marks]

ANSWER

(a)Schematic of a Nuclear Power Plant

Uranium-235 atoms are bombarded with neutrons. (1)The uranium atoms undergo fission with release of heat energy. (1)The heat energy is used to heat water into steam. (1)The steam produced will turn the turbine to generate electricity. (1)The electricity produced is then transmitted to consumers via electric cables. (1)(b) Advantages The radioactive fuel lasts a long time. A small quantity of radioactive substance can generate large amounts of energy. Disadvantages The gamma radiations emitted can cause cancer. Problems faced from storage of the by products as they continue to emit radiations for a long time.



18 (a) With examples explain the difference between isotopes and radioisotopes.[4 marks]

(b) Explain the uses of radioisotopes in the field of

(i) medical(ii) industry(iii) agriculture

[3 marks]

(c) State three precautions we have to take when handling radioisotopes.[3 marks]

ANSWER

(a) Isotopes are atoms with the same number of protons but different number of neutrons.Radioisotopes are isotopes that are radioactive and can undergo spontaneous decay.For example, carbon has carbon-12 and carbon-14 isotopes. The carbon-14 isotope is unstable and decays spontaneously. It is a radioactive isotope.(b) (i) Gamma radiation from the decay of uranium-235 is used to sterilize medical equipments and medicines.(ii) Gamma radiation from the decay of uranium-235 is used to detect canned food which is partially filled.(iii) Gamma radiation from the decay of radioactive phosphorus-32 is used to study the rate of absorption of phosphate fertilizer by plants.(c) Wear protective lead clothings and gloves.Use a dosimeter to measure the intensity of the radiation.Use remote control arms to handle the radioisotopes.



CHAPTER 7 : LIGHT, COLUR AND SIGHT

18 Study the following statement.

When white light is shone on two different primary coloured filters, no coloured light passes through, but when white light is shone on two different secondary filters, a certain coloured light passes through.

(a) Suggest a hypothesis to investigate the above statement.[1 mark]

(b) Using a red filter, a blue filter, a magenta filter, a yellow filter and other apparatus, describe an experiment to test your hypothesis in (a) based on the following criteria;· Aim of experiment [1 mark]· Identification of variables [2 marks]· List of apparatus [1 mark]· Procedure [4marks]· Tabulation of data [1 mark]

ANSWER

(a) A primary colour filter only enables its coloured light to pass through it and to absorb all other colour lights but a secondary colour filter enables its colour and the primary colour lights that form it to pass through it. (b) Aim of the experiment: To study absorption / subtraction of coloured light by a primary filter.Variables that are:(i) manipulated : the colour filter used(ii) responding : the colour on the white screen(iii) constant : white light from ray boxApparatus: Light box, glass prism, a red filter, a blue filter, a magenta filter, a yellowfilter and white screen.Procedure:

1. The apparatus as shown above is set up.2. The light box is switched on. The position of the white screen is adjusted so that the spectrum of

white light illuminats it.3. Two different colour filters (primary or a secondary as shown on the table below) are placed in

the path of the light beam at P and Q.4. The colours that pass through both filters and illuminate the screen are observed.

Tabulation of data:Filter P Filter Q Colours on screenRed Blue No colourRed Magenta Red Red Yellow Red Blue Magenta BlueBlue Yellow No colourMagenta Yellow Red



19 (a) Compare the image formed by a convex lens and a concave lens.[4 marks]

(b) The figure below shows several characteristics formed by an optical apparatus.

Study the characteristics of the image formed. Explain how you can determine the apparatus used and the phenomenon that occurred in the formation of the image based on the information in the figure above.Your explanation of the phenomenon should include the following:· Identify two criteria in the formation of the image· Identify the apparatus and develop the phenomenon· Give other example and non-examples of the characteristic of the image · Explain the Law of the phenomenon.

[6 marks]

ANSWER

(a)Properties of the image Convex lenses Concave lensesReal or virtual Real if the object distance is u > f . Virtual

if the object distance is u < fVirtual

Upright or inverted Inverted if the image is real, upright if the image is virtual

Upright

Position of the image Image is formed behind the lens if the image is real. Image is formed in front of the lens if the image is virtual

Image is always formed in front of the lens

Size of the image Bigger or smaller than the object depending on the object distance

Always smaller than the object

(b) Two criteria- The incident rays from the object strike a smooth and flat surface and reflected back - The angle of incidence, i is same as the angle of reflection, r.Apparatus and phenomenon- The optical apparatus is mirror and the phenomenon occurred is reflection.Example- The size of the image is the same as the object // the distance of image behind the screen is the same as the distance of the object in front of the screen.Non-examples- RealLaw of reflection:- The incident ray, reflected ray and normal all lie in the same plane.- The angle of incidence, i is equal to the angle of reflection, r.



20 (a) Compare and contrast the focusing and controlling of the amount of light in the human eye and a camera.

[4 marks]

(b) A student wants to observe a distant object. Explain how the student can build a device to observe the object. Your answer must include the following:· Problem statement · Name of the device built· Name the apparatus needed· The arrangement of the apparatus

[6 marks]

ANSWER

(a) Eye Function Camera The thickening and thinning of eye lens is controlled by the ciliary muscle that changes the focal length of the eye lens

Focusing method The camera lens moves forward and backward by adjusting the focus adjuster, which changes the distance between the lens and the film.

Light enters the eye through the pupil. The size of the pupil is controlled by the iris which controls the amount of light which enters the eye.

Controlling the amount of light that enters.

Light enters the camera through the aperture. The size of the aperture is controlled by the diaphragm. The shutter also controls the period of time the light enters the camera.

(b)Problem statement: To observe a distant object.Name of the device built: TelescopeName the apparatus needed: - Two convex lenses; one with a long focal length and the other one with a short focal length.The arrangement of the apparatus- The long focal length convex lens is used as an objective lens to focus parallel light rays from the distant object at its focal point.- The short focal length convex lens is used as the eye lens and is adjusted so that the image from the objective lens is at the focal point of the eye lens.



21 Steel is harder than pure iron.Carry out an experiment to prove the above statement. Your explanation must include the following:

· Aim of the experiment [1 mark]· Hypothesis. [1 mark]· Identification of variables. [3 marks]· Procedure [3 marks]· Tabulation of data [1 mark]· Conclusion [1 mark]

ANSWER

(a) To compare the hardness of steel and pure iron.(b) Steel is harder than pure iron.(c) Manipulated variable : Steel block and pure iron block Responding variable : Diameter of dent Constant variable : Height the weight is dropped onto the ball bearing.(d) A steel ball bearing is fixed onto a steel block using cellotape. A 1 kg weight is dropped onto the ball bearing from a height of 50cm. The diameter of the dent produced is measured, using a ruler. The experiment is repeated by replacing the steel block with pure iron block.(e)

Material Steel block Pure iron blockDiameter of dent (cm) p mm q mm

(f) The value of q > p. We conclude that pure iron is softer or steel is harder.



22 (a) Describe how ammonia is synthesized in industry.Your answer should include the following:(i) Name the process.(ii) State the sources of reactants.(iii) Optimum conditions to synthesize ammonia(iv) Word equation to represent the process

[7 marks] (b) State three uses of ammonia.

[3 marks]

ANSWER(a) (i) Haber process (1) (ii) Nitrogen is obtained from fractional distillation of liquid air. Hydrogen is obtained from natural gas. (2) (iii) Pressure of 200 atmosphere, temperature of 450oC and iron powder is used as catalyst. (3) (iv) Nitrogen + hydrogen ammonia (1)(b) To make fertilizer, nitric acid and prevent coagulation of latex. (3)

23 (a) Define what is an alloy. [2 marks](b) Give an example of alloy and its composition. [2 marks](c) State a use of the alloy in (b) above. [1 mark](d) Explain using the arrangement of atoms, why an alloy is harder than its pure

metal.[5 marks]

ANSWER(a) An alloy is a mixture of two or more metals in a certain percentage.(b) Bronze. (90% copper and 10% tin)(c) Bronze is used to make medals.(d)

The atoms in pure metals are arranged in a regular pattern. When a force is applied to it, the atoms will slide across each other. Thus pure metal is soft. (2)

The diagram above shows the presence of foreign atoms in an alloy. The foreign atoms prevent the metal atoms from sliding when a force is applied to it.Thus alloy is harder. (1)



FORM 5 -Chapter 1 – Microorganisms and their effects on living things

1 Study the following statement;

Sunlight affects the activities of microorganisms

(a) Suggest a hypothesis to investigate the above statement. [1 mark]

(b) Using few petri cultures of Bacillus subtilis, describe an experiment to test your hypothesis in (a) based on the following criteria;

· Aim of the experiment [1 mark]· Identification of variables [2 marks]· List of apparatus and materials [1 mark]· Procedure [3 marks]· Tabulation of data [1 mark]· Conclusion [1 mark]

Answer

1 (a) Hypothesis: Strong sunlight kills / stops the activities of microorganisms

(b) Aim: To study the effect of sunlight on the activities of microorganism

Constant variable: Nutrient / pH of the nutrient / amount of bacteriaManipulated variable: exposition to lightResponding variable: number of bacteria coloniesApparatus and materials: 3 petri cultures of Bacillus subtilis with their sterile covers,Procedure:

(i) The 3 petri dishes with culture of Bacillus subtilis were covered with their sterile covers respectively and overturned.(ii) The dishes were labelled A, B and C. Petri dish A was put inside a dark cupboard. Petri dish B was put on the lab table and Petri dish C was put under the ultraviolet light.(iii) The dishes were left aside for 2 days.(iv) The observation was recorded.

Tabulation of data:Petri dish ObservationABC

Conclusion:Petri dish A shows the number of bacteria colonies and Petri dish C shows none. Sunlight stops the activities of the microorganism. Hypothesis is accepted.



2 (a) Bacteria and alga are microorganisms. Somehow there are differences between the two microorganisms. State four differences in the properties between bacteria and alga.

[4 marks]

(b) The figure above shows two loaves of bread A and B made by two students A and B respectively.

State the difference between bread A and bread B.

Describes how student B can bake bread like student A. Your explanation must have the following criteria:· Problem statement· Name the ingredient needed· State how the action of the ingredient helps to bake a better bread

[6 marks]

ANSWER :2(a)

Properties Bacteria AlgaSize /µm 0.5 -10 1 - 1000Shape Rod, sphere, comma, spiral Variety shapeUnicellular / Multicellular

Unicellular Multicellular

Nutrition Saprophyte, parasite and autotroph

Autotroph

(b) Bread A is light and fluffy but bread B is small and hard Bread B lacks one ingredient that makes the dough not rise and not fluffy. Yeast Yeast breaks down the glucose in the bread dough and releases carbon dioxide gas. Carbon dioxide gas makes the dough rise and the bread becomes light and fluffy.



3 (a) Using heat or chemical are two ways of sterilization. Describe two methods for each way to show how sterilization is carried out.

[4 marks]

(b) Study the picture above and construct a concept of how transmission of disease occurs through a vector.

Your answer must be based on the steps below:· Identify the common characteristics [2 marks]· Relate the common characteristics to the transmission of disease through

the vector in order to construct the initial concept [1 mark]· Give an example of another transmission of disease through the vector

and a transmission of disease not through the vector [2 marks]· State the actual concept of transmission of disease through the vector. [1 mark]

ANSWER :

3(a) Heat : 1 : Boiling in water at 100º C for 6 hours2 : Heating for 15 minutes in the autoclave at 121º CChemical : 1: Antiseptic applied on injured skin to prevent reproduction of pathogen2: Disinfectant used in cleaning and mopping.

(b) Mosquito transfers pathogen to humanFly transfers pathogen to the food and food is eaten by human Mosquito and fly carry the pathogen from a patient to a healthy personExample : Rat Not examples : Ant, Bee The vector is an animal that carries the pathogen from a patient to a healthy person



CHAPTER 2 – Nutrition and food production

4Plants do not grow healthily when lacking in certain nutrients

(a) Based on the above statement and using the minerals of nitrogen, phosphorous, and potassium, write one suitable hypothesis.

[1 mark](b) Using a complete culture solution, culture solution without nitrogen, culture solution

without phosphorous, culture solution without potassium and other apparatus, describe an experiment that you carry out in the laboratory to prove the hypothesis.

Your description should include the following;

(i) aim of experiment [1 mark](ii) identification of variables [2 marks](iii) list of apparatus and materials [1 mark](iv) procedure [4 marks](v) tabulation of data [1 mark]

ANSWER :

4(a) Deficiency in nutrient nitrogen, phosphorous and potassium hinder the growth of plants.

(b) Aim : To study the effects of nitrogen, phosphorous and potassium deficiency on the plant growth.

Constant variable : germinating seed, frequency of changing solution Manipulated variable : culture solutionResponding variable : rate growth of germinating seedApparatus and materials : cotton, black paper, germinating seeds, complete culture solution, culture solution without nitrogen, culture solution without phosphorous, culture solution without potassium, measuring cylinder and 4 boiling tubes

Procedure : 1) 4 boiling tubes were labelled and filled with culture solution as shown below:



2) Mouths of boiling tubes were closed with cotton and one germinating seed was put in each tube.3) Each boiling tube was wrapped with black paper.4) All the boiling tubes were put on a rack and left exposed to sunlight.5) After a week, the culture solutions were changed to new ones.6) Observation of each germinating seed was done for two weeks and the results were recorded.

Tabulation of dataBoiling tube Observation

ABCD

5 (a) The calories requirement per day of the two people in the figure below is not the same. Identify the factors that affect the calories requirement per day for the individuals below.

Give three explanations how they affect the calorie requirement per day.[4 marks]

(b) The figures below show three different diseases caused by malnutrition.



Figure (i) : Ricketts Figure (ii) : Scurvy Figure (iii) : Goiter

Study the diseases in the figures above and explain how you construct the concept of malnutrition.Your answer should be based on the following steps:· Identify the information· Identify the common characteristics· Relate the common characteristics to malnutrition in order to construct the initial

concept· Give other examples and non-examples in relation to the concept· State the actual concept of malnutrition

[6 marks]ANSWER:5 (a) sexA man requires more calories than a lady because;(i) size and weight of a man is bigger than a lady(ii) metabolism of a man is higher(iii) a man is more active physically

(b)Identify the information The diseases are caused by malnutrition for a

long period of timeIdentify the common characteristics

The diseases above are due to deficiency of one class of food respectively in daily diet.(i) Ricketts - deficiency of vitamin D(ii) Scurvy - deficiency of vitamin C(iii) Goiter - deficiency of iodine

Relate the common characteristics to malnutrition in order to construct the initial concept

Deficiency of one class of food in daily diet may lead to malnutrition.

Other examples

Non-examples

Kwashiorkor / Anemia / Night blindness

Obesity / Arteriosclerosis / Diabetes State the actual concept of malnutrition

Malnutrition is a state when an individual suffers from food deficiency in one or two necessary food classes in his daily diet to maintain a healthy body.



CHAPTER 3-Preservation & conservation of the environment

6

The figure above shows Mr. Johnny's farm. He plants leafy vegetables, rear fresh water fish and poultry for sale. He uses chemical fertilizers and pesticides to maintain and increase the yield of his vegetables.State the four effects of excessive use of chemical fertilizers and pesticides.

[4 marks]After some time, he finds that the surface of the pond is covered with a layer of green substance and the fish has died.Explain how Mr. Johnny overcomes the problems in his pond.Your answer should include the following;· Identify the problem· State the phenomena· Clarification of the problem· Solving methods

[6 marks]ANSWER : 6.Excessive fertilizer that flows to river and pond encourages the growth of alga.Alga prevents sunlight from reaching the bottom of the river or pond, aquatic plants cannot undergo photosynthesis and therefore die.The content of oxygen in the water decreases.Pesticides hardly decompose, but flow into the pond or river and are eaten by the aquatic animals, causing death or passing on into the food chain.

Identify problems Alga grows on the water surface and the diesPhenomena Eutrofication Clarification of the problem

Excessive fertilizer and waste from the poultry contain nitrate and phosphate compounds which encourage the growth of alga. Pesticides from the vegetable farm contain DDT which is harmful to living organisms.

Solving methods Convert the poultry waste into compost fertilizer. Use compost fertilizer instead of chemical fertilizer Use biological pest control methods instead of pesticides.

7 (a) Improper management of open land to give way for development has caused a number of



side effects on the balance in nature.State four side effects caused by improper management of open land.

[4 marks]

(b) The figures (i) and (ii) below show activities which happened in our surroundings that caused global warming.

Study the above activities. Explain how you would be able to construct the concept of global warming.Your answer should be based on the following steps:· Identify the common characteristics· Relate the common characteristics to the change of environment in order to construct

the initial concept· Give an example of other forms of pollution and a non-example in relation to the

concept.· State the actual concept of global warming

[6 marks]

ANSWER :7(a) extinction of species

loss of habitatsoil erosionflash flood

(b) Identify the common characteristics

Combustion of fuel release carbon dioxide into the air.Cutting down of trees eliminates the process of photosynthesis of the trees, indirectly increasing the content of carbon dioxide in the air

Construct the initial concept

Carbon dioxide in the air prevents heat from leaving the atmosphere, thus increasing the temperature on the earth which is named global warming

Another exampleNon example

Forest fire / open burning of rubbishDisposal of byproducts, waste, toxic substances, radioactive substances, smoke and heat / uncontrolled use of chemical fertilizers

State the actual concept of global warming

Global warming is the rise in earth temperatures due to the increase of greenhouse gases like carbon dioxide.

CHAPTER 4 – Carbon Compounds



8 A rubber planter adds ammonia into latex to maintain its liquid state and sells it in liquid state. To some latex, he adds formic acid and sells it as solid rubber.

(a) Based on the above statements, write one suitable hypothesis.[1 mark]

(b) With the material of latex, acetic acid and ammonia, describe an experiment that you can carry out in a laboratory to prove the hypothesis.Your description should include the following;

(i) aim of experiment [1 mark](ii) identification of variables [2 marks](iii) list of apparatus and materials [1 mark](iv) method [3 marks](v) how to tabulate the data [1 mark](vi) conclusion [1 mark]

ANSWER :

8(a) Hypothesis : Alkaline prevents coagulation of latex and acid coagulates the latex.

(b) (i) To study the effects of alkaline and acid on latex(ii) manipulated variables: ammonia and acetic acid responding variables: condition of latex / coagulation of rubber constant variables: volume of latex(iii) apparatus and materials: latex, acetic acid, ammonia, beaker, measuring cylinder

(iv) method: 1. Latex is measured with a measuring cylinder and poured into 2 beakers2. Ammonia and acetic acid are poured into the respective beakers.3. The mixtures are stirred and left for 10 minutes. Observations are recorded.

(v) DataBeaker ObservationAB

(vi) Conclusion: Ammonia prevents the latex from coagulating and acid causes coagulation of latex

9 (a) State three differences between organic carbon compound and non organic carbon YL KONG @SMKSARATOK2008


compound. Name an example for each respective group.[4 marks]

(b) The figure below shows the products of hydrocarbon.

Study the products above and construct the concept of hydrocarbon. Your answer should be based on the following steps;· Identify two common characteristics· Develop initial concept· Give an other example and a non-example in relation to the concept · Explain the actual concept

[6 marks]ANSWER:

9 (a) Organic carbon compound Non organic carbon compound

Carbon compound which has originated from living organisms.

Carbon compound which has originated from non living thing such as minerals.

Carbon chain which has many carbon atoms.

Molecule with few carbon atoms only.

Dissolve in organic solvent.Eg: alcohol

Dissolve in non-organic solvent Eg. water

Starch Carbon dioxide (b)

Common characteristics The products are hydrocarbon compound which consists of carbon and hydrogen elements.The products have originated from living organisms which died millions of years ago

Initial concept The products are from the sources of fossil fuelExampleNon-example

Natural gasMineral such as calcium carbonate

Actual concept Hydrocarbon is organic carbon compound which consists of the carbon and hydrogen elements and has originated from living organisms which died millions of years ago

10 (a) Butter and margarine are used to made cakes and cookies.



State four differences between butter and margarine based on the following;· Sources· Structure of atom· Physical properties· Effect on health

[4 marks]

(b) An officer whose favourite foods are cakes and cookies, finds that her low density cholesterol level in the blood test is slightly higher.Explain how the officer can solve or remedy her situation since she cannot give up her favorite foods.Your explanation should include the following;· Problem statement· State the effects on the body· Suggest a diet to replace the present diet

[6 marks]

ANSWER :

10 (a)Butter Margarine

Sources animal PlantStructure of atom Saturated fat with single bond

between carbon atomUnsaturated fat with at least one double bond between the carbon atom

Physical properties Solid at room temperature Liquid at room temperatureEffect on health Increase level of cholesterol Decrease level of

cholesterol (b)

· Low density cholesterol in the blood is slightly high.· Low density cholesterol deposits on gall bladder as gall bladder stones· Low density cholesterol deposits on the insides of the wall of the artery may cause

high blood pressure, heart disease, arteriosclerosis and coronary thrombosis· Use margarine in making the cake and cookies· Add fiber, fruits and, vegetables such as carrot into the cake Eg: Apple cake, Carrot cake



CHAPTER 5 - Motion

A moving heavy vehicle has higher momentum

11 (a) Based on the statement above, suggest a hypothesis.

[1 mark]

(b) Using four trolleys, an inclined plane, a wooden block, plasticine and other apparatus, describe an experiment to test your hypothesis in (a) based on the following criteria:(i) aim of experiment [1 mark](ii) identification of variables [2 marks](iii) list of apparatus and materials [1 mark](iv) procedure [4 marks](v) tabulation of data [1 mark]

ANSWER :11(a) Hypothesis: The bigger the mass of moving object is, the higher the momentum.(b) Aim of experiment: To study the relationship between momentum and the mass of moving

object.Variable that is(i) constant : the gradient of inclined plane(ii) manipulated : Mass of the trolley(iii) responding : the distance of the trolleys stopList of apparatus and materials : trolleys, an inclined plane, a wooden block, plasticine and a

metre ruler.Procedure:

1. The apparatus are arranged as shown above.2. Trolley X is released to go down the inclined plane and collide with trolley Y3. Trolley X and Y are stuck after the collision and move together4. The distance where the trolleys stop from the spot of collision is measured and

recorded.5. The experiment is repeated with two trolleys at X position and three trolleys at X

position respectively to collide with one trolley on Y position.Tabulation of data

Number of trolleys Distance the trolleys stop123



12 (a) A big ship is made of a mixture of iron. The figures above show that a piece of iron sinks into the sea whereas a big ship floats on the sea. Explain why.

[4 marks]

(b) A student makes a simple hot air balloon model as shown above for his science project. He finds that his model could not fly.Explain how to make his hot air balloon fly.Your explanation should include the following· Problem statement· State the concept and principle used· Solving methods

[6 marks]ANSWER :12(a)

Iron ShipA piece of iron has a small volume, thus the mass divided by volume produces a higher density

The iron pieces in the ship are moulded into a shape with a large volume of empty space at the centre. The density of the ship becomes smaller.

The weight of water displaced is less than the weight of the piece of iron. Therefore, the iron sinks

The big ship displaces a large volume of water where the weight of the water displaced is the same as the weight of the big ship. Therefore the big ship floats.

(b) Problem statement: The hot air balloon could not fly.Concept used:1. The hot air inside the balloon is less dense than the cool air outside.2. The upthrust of the hot air balloon must be more than the weight of the balloon.3. The principle used is Archimedes' principle.Solving methods:4. Increase the size of the balloon to displace more cool air by the hot air inside the balloon.5. A bunsen burner is lighted at the bottom of the balloon to heat the air inside the balloon.



CHAPTER 6 – Food technology and production

Processed food can last longer than non-processed food if left exposed to open air

13 (a) Based on the statement above, suggest a suitable hypothesis.

(b) Using a fresh non-processed milk, a boiled milk, a pasteurised milk and other apparatus, describe an experiment to test your hypothesis in (a) based on the following criteria:

· Aim of experiment [1 mark]· Identification of variables [2 marks]· List of apparatus and materials [1 mark]· Procedure [3 marks]· Tabulation of data [1 mark]· Conclusion [1 mark]

ANSWER :13(a) Hypothesis: Processed food can last longer than non-processed food if left exposed to

open air.(b) Aim : To identify the processed food that can last longer than non-processed food.

Variable that is;(i) manipulated : the method of processed milk(ii) responding: the condition of the milk(iii) constant: the volume of milk

List of apparatus and material: fresh non-processed milk, boiled milk, pasteurised milk, 3 beakers, measuring cylinder Procedure:1. Three sterile beakers are prepared. Beaker A is filled with fresh non-processed milk, beaker

B is filled with boiled milk and beaker C is filled with pasteurised milk. 2. The beakers are left in the open air for one day.3. Observe the condition and the smell of the milk after one day and record in the table below.

Result:Beaker Observation

ABC

Conclusion:Non-processed milk becomes rotten faster than boiled and pasteurised milk. Pasteurised milk lasts longer than fresh non-milk and boiled milk.

14 (a) The world population growth is much faster than the production of food. Explain how the property of quality breeds can help to increase the production of food.



(b) A vegetable farmer found his farm is no longer productive and is having problems with a pest on his farm.Explain how the farmer on his farm can overcome his problems on his farm.Your answer should include the following;

· Aim of experiment [1 mark]· Clarification of the problem [1 mark]· Solving methods [3 marks]· Choose the best method and explain your choice [1 mark]

ANSWER :14(a) Property of quality breeds:(i) high quantity of production (ii) high quality of production(iii) short production period(iv) high resistance towards disease and pest

(b) Identify the problem The farmer's farm is no longer productive and

is attacked by a pest.Clarification of the problem The soil is not fertile anymore due to intensive

use by certain kind of plant.The pest has formed a high resistance towards the pesticide used.

Solving methods Crop rotation to regain the fertility of the soil.Mixed crops to regain the problem of the pest and at the same time can regain the fertility of the soil.Integrated system that is to rear poultry together with plants.

Best method Mixed crops to reduce the problem of the pest, and at the same time can regain the fertility of the soil.

CHAPTER 7 – Sythetic Materials in the industry



Synthetic rubber is not easily burned compared to natural rubber

16 (a) Suggest a hypothesis to investigate the above statement[1 mark]

(b) Using a synthetic rubber strip, a natural rubber strip and other apparatus, describe an experiment to test your hypothesis in (a) based on the following criteria:

· Aim of experiment [1 mark]· Identification of variables [2 marks]· List of apparatus and materials [1 mark]· Procedure [3 marks]· Tabulation of data [1 mark]· Conclusion [1 mark]

ANSWER :16(a) Hypothesis : Natural rubber burns more easily than synthetic rubber

(b) Aim : To compare the characteristic of synthetic rubber and natural rubber towards burning.

Variable that is; (i) manipulated: type of rubber(ii) responding: ability to burn(iii) constant: time of heatingList of apparatus: a synthetic rubber strip, a natural rubber strip, Bunsen burner, tongs

Procedure :

1. A synthetic rubber strip is burned with a Bunsen burner for 5 minutes as shown above. The observation is recorded.

2. A natural rubber strip is burned with the same Bunsen burner for 5 minutes. The observation is recorded.

Tabulation of data:Characteristic Synthetic rubber Natural rubberAbility to burn Not easily burnt Burns with lots of soot

Conclusion:Natural rubber burns easily with lots of soot whereas synthetic rubber does not burn easily. Hypothesis is acceptable.



17 (a) The figure above show the products of thermoplastic. State four reasons why the above products are thermoplastic and not thermoset.

[4 marks]

(b) A local council found that the rubbish dumped by the public mostly is made of plastic.Explain how the local council can solve the problem of disposal of plastic rubbish. Your explanation should include the following:

· Identify the problem [1 mark]· Clarification of the problem [1 mark]· Solving methods [3 marks]· Choose the best method and explain your choice [1 mark]

ANSWER :17(a) - the products have low resistance toward heat- the products are soft- the products can be recycled as the material can be moulded few times- the products do not have cross linkage between the polymers chain- the products have low melting point

[any 4 points](b)

Identify the problem Plastic rubber is not biodegradable and causes environmental pollution.

Clarification of the problem How can we reduce environmental pollution caused by plastic rubbish?

Solving methods 3. Use biodegradable plastic which can be decomposed by microorganism.

4. Burn the disposed plastic in an incinerator.5. Recycle the disposed plastic into plastic

product that can be used again6. Reuse the plastic for other purposes.

Choose the best method and explain your choice

Recycle because thermoplastic can be moulded a few times as it can reduce the disposal of plastic and save sources of plastic raw materials

18 (a) Polymer synthetic is very useful in modern life. Describe four negative effects of the YL KONG @SMKSARATOK2008


consumption and disposal of polymer synthetic in the environment.[1 mark]

(b)

The figure above show the plastic which can be recycled. Study the information above and construct the concept of recycling. Your answer should be based on the following steps:

· Identify two common characteristics [2 marks]· Develop initial concept [1 mark]· Give an example of another recycleable and non-recycleable

plastic[2 marks]

· State the actual concept of recycleable plastic [1 mark]

ANSWER:18(a) (i) Polymer synthetic is not biodegradable and it will be in the environment for a long period which may cause environmental pollution. (ii) Open burning of polymer synthetic releases soot and toxic gases such as dioxin which may cause air pollution and public health problem. (iii) Disposal of plastic in the drainage may cause blockage of drainage system and flash flood. It may encourage the breeding of mosquitoes. (iv) Disposal of plastic in sea and river may cause extinction of turtle and other aquatic life.

(b) Two common characteristics The plastics can be repeatedly moulded into a variety

of shapes.The polymer chains of the plastic can slide from one to another when heated and come together when cooled.

Initial concept Plastic which can be recycled is the plastic which can be repeatedly moulded into various shapes and the polymer chains can slide from one another when heated.

Example Non example

Polypropene / polystyreneBakelite / melamine / epoxy glue

Actual concept Thermoplastic can be recycled for other purposes that can be moulded into new products

CHAPTER 8- Electric and information and communication technology



Study the following statement.

The brightness of a bulb varies with the number of resistors in a circuit.

19 (a) Suggest a hypothesis to investigate the above statement.[1 mark]

(b) Using three resistors, a bulb and other apparatus, describe an experiment to test your hypothesis in (a) based on the following criteria;· Aim of experiment [1 mark]· Identification of variables [2 marks]· List of apparatus and materials [1 mark]· Procedure [3 marks]· Tabulation of data [1 mark]· Conclusion [1 mark]

ANSWER :19(a) Hypothesis: The more the number of resistors used in a circuit, the dimmer the

light of the bulb.(b) Aim of the experiment: To study the effect of resistors on the brightness of a bulb.

Variable that is;(i) constant: number of dry cell / power of the bulb(ii) manipulated: number of resistors(iii) responding: the brightness of the bulb

List of apparatus: 3 resistors, bulb, dry cell, connection wire and switch



Procedure:

1. The above circuit is prepared.2. Switch is on and the brightness of the bulb is observed.3. A resistor is taken away and switch is on. The brightness of the bulb is observed

again.4. Step 3 is repeated with one resistor left. 5. The results of the observations are recorded in the table below

Tabulation:No. of resistor Brightness of bulb

321

Conclusion:As the number of resistors decreases, the brighter the bulb is. Hypothesis is acceptable.

20 (a) A radio wave is used in long distance communication. Give four reasons why a radio wave is used in information communication.

[4 marks]

(b) The table below shows types of radio waves used in radio communication.Local radio broadcasts Long Wave with low frequency

Radio broadcasts across continent Short Wave with high frequencyTV Astro broadcasts Microwaves

Study the information in the table above and construct the concept of radio communication. Your answer should be based on the following steps:· Identify the information [1 mark]· Identify the common characteristics [2 marks]· Relate the common characteristics to the radio communication in order

to construct the initial concept.[1 mark]

· Give an example of another radio communication and a non radio communication

[1 mark]

· State the actual concept of radio communication [1 mark]ANSWER:



20(a) - It can travel through vacuum - It moves with the speed of light, so it can transmit the information very fast. - It acts as a carrier wave for audio and video signals - It is not easy to be spread through an obstruction (b)

Identify the information Local radio broadcast use the long wave with low frequency of the radio wave as a carrier wave to deliver sound information

Identify the common characteristics

- Radio broadcasts across continent use short waves with high frequency of the radio wave as a carrier wave to deliver sound information - TV Astro broadcasts use microwaves with the highest frequency of radio wave as a carrier wave to deliver sound and picture information

Relate the common characteristics to the radio communication in order to construct the initial concept.

All the three radio communications above use the wave of different frequency of radio waves in electromagnetic spectrum as the carrier wave to deliver information.

An example

Non example

Hand phone / FM radio broadcast

Microwave ovenActual concept of radio communication

Radio communication is using a range of radio waves in the electromagnetic spectrum as carrier to deliver information



21 (a) State four advantages of satellite communication system to other communication system.[4 marks]

(b) Football World Cup 2006 was held in Germany. A remote country could not get the live television broadcasts for the tournament. Explain how the country can solve the problem so that they can watch the matches live in the next tournament. Your answer should include the following:

· Clarification of the problem [1 mark]· Name the system of communication [1 mark]· Steps for the system to function [4 marks]

ANSWER:21(a) - transmission or receiver of satellite system is not affected by the change in weather.- it can service a wide area including the remote area- it does not need many relay station as microwave can move very far- it can deliver a lot of information quickly and efficiently - it can transmit live broadcasts through-out the world

(b)Clarification of the problem How to get live television broadcasts?

System of communication Use satellite communication system

Steps of the system to function An earth satellite station is built in the country.Television camera will record the match in the stadium where and when the tournament is on.The electrical signal will be sent to the television station and be transmitted by micro wave by the earth satellite station of the host country to the communication satellite in space.The communication satellite in space will strengthen and transmit back to the earth's satellite station in the remote country, and then to the local television station.










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