Summary of Form 4 Topics

Chapter 1       Physical Quantity

1.         A physical quantity is a quantity that can be measured and consists of a numerical magnitude and a unit.
2.         Physical quantities can be classified into two types: base quantities and derived quantities.
3.         Five of the base quantities are length, mass, time temperature and electric current.

Base quantity
Simbol
SI unit
Symbol for the unit
Length
l
Metre
m
Mass
m
Kilogram
kg
Time
t
Second
s
Temperature
T
Kelvin
K
Electric current
I
ampere
A

4.         Derived units are constructed using the base units.

Physical quantity
Symbol
Relation with base quantity
Formula
SI units
Volume
V
Length (m) × Length (m) × Length(m)
V = l3
m3
Velocity
v
Displacement (m) / Time (s)
v = s/t
ms3
Density
ρ
Mass (kg) / Volume (m3)
ρ = m/V
kg m-3
Force
F
Mass (kg) × Acceleration (m s-2)
F = ma
N
Electric charge
Q
Current (ampere) × time (s)
Q = It
C

5.         In scientific notation, the numerical part of a quantity is written as a number between 1 and 10 multiplied to the power of a whole number.
M × 10 n,             1 < M < 10 and n is an integer.

6.         Prefixes.
Prefix
Symbol
Standard Form
Example
Tera-
T
1012
Terametre (Tm)
Giga-
G
109
Gigabyte (GB)
Mega-
M
106
Megawatt (MW)
kilo-
k
103
Kilometre (km)
hecto-
h
102
Hectometre (hm)
deka-
da
101
Dekametre (da m)
deci-
d
10-1
Decimetre (dm)
centi-
c
10-2
Centimetre (cm)
milli-
m
10-3
Milligram (mg)
micro-
μ
10-6
Microwatt (μW)
nano-
n
10-9
Nanosecond (ns)
pico-
p
10-12
Pikometre (pm)

7.         A vector quantity has both magnitude and direction.
8.         A scalar quantity has magnitude but no direction.
9.         The resultant force of two vectors acting at a point can be found using the parallelogram method.



Chapter 2       Measuring Process

1.         A micrometer can be used to measure up to accuracy of 0.01 mm.
2.         A vernier calliper can be used to measure up to accuracy of 0.01 cm.
3.         The volume of liquids can be measured with a measuring cylinder, pipette and burette.
4.         Time can be measured with either an analogue of digital stopwatch. However, the digital stopwatch is more accurate.
5.         Consistency is a set of readings that are close to each other.
6.         Accuracy is a measurement that is close to the actual value of the quality being measured.
7.         A graph must be drawn with the best line through the points.
8.         In plotting a graph, we must know the manipulated variable and the responding variable.


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Chapter 3       Energy

1.         Energy is the capacity to do work.
2.         The energy of motion is kinetic energy.
3.         Kinetic energy, .
4.         Potential energy is stored energy.
5.         Change in gravitational potential energy.
6.         There are various forms of energy.
7.         Energy is neither created nor destroyed.
8.         Energy can be converted from one form to another.

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Chapter 4       Heat

1.         Heat is the thermal energy that is being transferred from a body or system to another as a result of a difference in temperature.
2.         When the rate of the transfer of thermal energy is the same for two objects in contact, the two objects are a state of thermal equilibrium.
3.         A mercury or alcohol thermometer works on the principle of expansion of liquids.
4.         In an electrical resistance thermometer, the resistance of a wire changes with temperature.
5.         The thermal energy required to overcome the attraction of the molecular forces is called latent heat.
6.         Specific latent heat of fusion (lf) of a substance is the quantity of heat needed to change a unit mass of the substance from solid to liquid without a change in temperature.
7.         Specific latent heat of vaporisation (lv) of substance is the quantity of heat needed to change a unit mass of the substance from liquid to gaseous state without a change in temperature.

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Chapter 5       Electricity

1.         Current flows from the positive to the negative terminal of a cell, but electrons move in the opposite direction.
2.         Current (I) is the rate of flow of electric charge (Q).
3.         The relationship between charge, current and time is given by the formula .
4.         An oscilloscope (CRO) can be used to display a waveform of the AC current.
5.         Potential difference, , where E = energy, Q = charge.
6.         Root mean square voltage, .
7.         Root mean square current, .
8.         Mean power = .

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Chapter 6       Sources of Energy

1.         During nuclear fission, the nucleus splits into two or more parts.
2.         Rods of cadmium are lowered into a reactor to control the reaction. The rods regulate the nuclear divisions by absorbing a number of freed neutrons.
3.         Energy released during fission heats water, creating high pressure steam. The steam is used to drive a turbine connected to an electrical generator.
4.         Nuclear fusion is the union of two small nuclei, such as those of hydrogen, to form another heavier nucleus, such as helium.
5.         Fusion occurs in a tokomak or in the sun.
6.         Solar energy can be harnessed in two main ways, which are for heating and for the production of electricity.
7.         Transparent materials used as covers will determine the amount of solar radiation absorbed.
8.         Biomass energy comes from plants that store the energy from the sun. The burning of biomass substances will produce energy.
9.         The kinetic energy of wind can turn the turbine of a windmill.
10.     At the bottom of the windmill, there is a generator the produces electricity.
11.     Geothermal energy is produced from heat in the earth’s crust.
12.     Exploration of renewable energy sources is important to the economies, society and the environment.
13.     There is a need to increase the efficiency of energy used.





Chapter 7       Periodic Table



1.         The Periodic Table contains elements arranged with their proton numbers in increasing order. The columns are called groups and the rows are called periods.
2.         The electron configuration of an element indicates its group and period. Elements in the same group have the same number of outermost electrons and similar chemical properties.
3.         The Group 1 elements (the alkali metals) are Li, Na, K, Rb, Cs and Fr. They are soft metals with low densities and melting point, and very reactive. The hardness and melting points decrease, but densities and reactivities increase on going down the group.
Equation: 2M + 2H2O à 2MOH + H2.
4.         Hydrogen is in Period 1 and in a group by itself.
5.         The Group 17 elements (the halogens) are F, Cl, Br, I and At. Their physical states change from gas (F2, Cl2) to liquid (Br2) to solid (I­2, At).
X2 + H2O à HX + HOX
X2 + 2NaOH à NaX + NaOX + H2O
X2 + 2Na à NaX
3X2 + 2Fe à 2FeX3

6.         The Group 18 elements (the noble gases) are He, Ne, Ar, Kr and Rn have low densities and boiling points. The boiling point increases on going down the group. Their atoms have a duplet or an octet arrangement of outermost electrons; they are inert gases.
7.         The last elements in Group 1, Group 17, Group 18 and all actinoids are radioactive. Elements with proton number 92 and higher are synthetic and radioactive.
8.         The period 3 elements are Na, Mg, Al, Si, P, S, Cl, Al are metals, Si is a metalloid and P, S, Cl and Ar are non-metals. Oxides of the metals are basic; while silicon dioxide and oxides of the non-metals. Oxides of the metals are basic; while silicon dioxide and oxides of the non-metals are acidic.
MgO + 2HCl à MgCl2 + H2O
SiO2 + 2NaOH à Na2SiO3 + H2O
S + O2 à SO2; SO2 + H2O à H2SO3

9.         The transition elements in Period 4 are in Group 3 to Group 12 (Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu and Zn). They are metals, solid, have high densities and melting points and they formed coloured compounds.
10.     An element is made of one type of atoms only. A compound is made of two or more different types of atoms. Matter can exist as elements, compounds and mixtures.








Chapter 8       Chemical Bonding

1.         Atoms or ions with the duplet or octet valence electron configuration are stable.
2.         Atom achieves a stable electron configuration by sharing, donating or receiving valence electrons.
3.         Atoms of metals donate one or more valence electrons to become positive ions.
4.         Atoms of non-metals receive one or more valence electrons to become negative ions.
5.         Non-metallic atoms share one or more valence electrons to achieve the duplet or octet valence electron configuration.
6.         An ionic compound is the electrostatic force of attraction between a positive ion and a negative ion.
7.         An ionic compound is formed from a metal and a non-metal.
8.         Ionic compounds are insulators in the solid state; conductors when melted of dissolved in water and have high melting points. Some ionic compounds are soluble in water.
9.         A covalent bond is the electrostatic force of attraction between the shared electrons and the nuclei of both atoms.
10.     Covalent compounds are insulations, generally have low melting points and most of them are insoluble in water.
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Chapter 9       Mole Concept

1.         Relative atomic mass of X = 
2.         Relative molecular mass of X = 
3.         Relative molecular mass of Xa = a × Relative atomic mass of X
4.         Relative molecular mass of XaYb = (a × Relative atomic mass of X) + (b × Relative atomic mass of Y)
5.         1 mol = 6.02 × 10 23 = Avogadro’s number.
6.         Number of moles of atoms = 
7.         Number of moles of molecules = 
8.         Number of atoms = Number of moles of atoms × Avogadro’s number.
9.         Number of molecules = Number of moles of molecules × Avogadro’s number.
10.     Balanced chemical equation: Number of atoms of reactants = number of atoms of products.

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Chapter 10     Respiratory System


1.         The lungs are organs that facilitate the intake of oxygen and elimination of carbon dioxide.
2.         Respiration is the oxidation of glucose with the release of energy in living cells.
3.         The energy is used to perform activities in the cells.
4.         There are two types of respiration; aerobic and anaerobic respiration.
5.         Aerobic respiration involves the breakdown of glucose in the presence of oxygen, releasing a large amount of energy (36 ATP). Carbon dioxide and water are released as waste products.
6.         Anaerobic respiration in human involves breakdown of glucose with the release of a small amount of energy (2ATP) and acid lactic in the absence of oxygen.
7.         Anaerobic respiration occurs in the absence of oxygen in yeast producing ethanol and carbon dioxide.
8.         In human muscle cells, anaerobic respiration produces lactic acid.
9.         When oxygen enters the blood in our lungs, it binds with the haemoglobin in the red blood cell to form oxyhaemoglobin and is transported to the tissues and organs. Carbon dioxide is transported in the form of carbonic acid and carbaminohaemoglobin from the body cells to the lungs where it is expelled.
10.     In case of lung failure, a ventilator or respirator can assist breathing.
11.     Cardiopulmonary resuscitation (CPR) is an emergency treatment to assist an individual who is out of breath for a while before proper treatment can be carried out.
12.     Asthma, lung cancer, pneumonia and bronchitis are some of the diseases and illnesses infecting the lungs.
13.     Healthy lifestyle includes abstaining from smoking and doing regular exercises.
14.     Conservation of air is essential to ensure healthy air quality.

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Chapter 11     Digestive System

1.         The human digestive system consists of mouth, salivary glands, oesophagus, stomach, liver, gall bladder, pancreas, duodenum, ileum, colon, rectum and anus.
2.         Digestion is the process of breaking down food molecules into smaller molecules that can be absorbed by cells.
3.         There are two types of digestive processes: that is mechanical and chemical.
4.         Chemical digestion involves hydrolysis that is catalysed by enzyme.
5.         Enzymes need suitable environments to function actively. Their activity will depend on factors such as pH and temperature.
6.         Gastritis, constipation, appendicitis and diarrhoea are some diseases related to the digestive system.
7.         People who practice good nutrition, hygiene and exercise regularly are healthy for many years. Therefore, we must practice good eating habits.

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Chapter 12     Circulatory System

1.         Blood has two major constituents; plasma and cellular elements.
2.         Plasma plays a role in carrying dissolved substances, as well as being involved in osmotic balance and pH buffering.
3.         Red blood cells transport oxygen and carbon dioxide. White blood cells are involved in defence and immunity. Platelet is important in blood clotting.
4.         Blood types depend on the antigen on the red blood cells: antigen A and antigen B.
5.         Plasma also contains proteins called antibodies: Anti-A and Anti-B.
6.         Blood compatibility depends on reactions between antigens and antibodies.
7.         Rh factor is another group of antigens on the surface of red blood cells of humans.
8.         Blood clotting stops blood loss by clumping blood cells which are trapped by the fibrin strands and protect the wound from entry of harmful microorganisms.
9.         A cardiac cycle is made of an auricular systole, a ventricular systole and a complete auricular ventricular diastole.
10.     Heartbeat increases when blood pressure rises and decreases when blood pressure drops.
11.     The lymphatic system cleanses the lymph by collecting excess tissue fluid that leak from the capillaries and return them to the blood circulation.
12.     The flow of lymph: lymph capillary à lymph vessel à lymph node à lymph duct à larger lymph vessel à left or right subclavian vein à vena cava à heart.
13.     The lymphatic system filters lymph, fights infection and returns tissue fluid back to the circulatory system.

Chapter 13     Excretory System

1.         Excretion is the process of moving metabolic wastes products and toxic materials, such as urea, ammonia and uric acid.
2.         Kidneys and skin play an important role in excretion.
3.         Defecation is removing indigestion food from digestive system.
4.         Urine formation involves three processes : Filtration, selective reabsorption and secretion.
5.         Skin removes toxic wastes from the body through sweating. Sweat is a mixture of water, salts and urea.
6.         We can prevent the kidney related diseases by reducing salt and sugar intake in our diet, drinking plenty of water, avoiding medications without proper prescription and avoiding drugs and alcohol.











Chapter 14     Reproductive System

1.         The menstrual cycle is a cycle of physiological events of the female reproductive system in every 28 days.
2.         The menstrual cycle, involves changes in hormone levels which in turn causes changes to the ovaries and uterus.
3.         The four hormones that affect the cycle are follicle stimulating hormone (FSH), luteinizing hormone (LH), oestrogen and progesterone.
4.         Spermatogenesis is the development of male gametes or sperm cells that occurs in the testes, which is triggered by the hormone FSH.
5.         Oogenesis is the development of an ovum that takes place in the ovary.
6.         The fusion of the haploid sperm and haploid egg nucleus to produce a diploid zygote is called fertilisation.
7.         Reproductive technology such as In Vitro Fertilisation (IVF), Gamete Intra Fallopian (GIFT) and Zygote Intra Fallopian (ZIFT) help to solve infertility problems.
8.         The foetal phase is the beginning of the 9th to the 40th week, where organs begin to function and growth rapidly.
9.         Amniotic fluid protects the foetus from mechanical damage by cushioning sudden movements, facilitates the movement of the foetus and maintains a relatively constant temperature in the environment surrounding the foetus.
10.     The placenta secretes estrogen and progesterone, allows exchange of nutrients and waste between maternal and foetal circulation, and acts as a partial barrier from harmful substances.
11.     Birth occurs in three stages: dilatation, delivery and afterbirth.
12.     An infected reproductive system can cause illness and infertility. Sexually transmitted infection (STI) involves infections that can be passed from an infected partner to his or her partner during sexual intercourse.

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Chapter 15     Biodiversity (Biokepelbagaian)

1.         Biodiversity refer to the diversity of biological resources. (kepelbagaian sumber hidup di dunia)
2.         Biodiversity includes genetic diversity, species diversity and ecosystem diversity.
3.         Abiotic factors include water, soil, sunlight, temperature and they influence the survival of the biotic components in the different ecosystems.
4.         The interrelationships between the abiotic and biotic components have created three major ecosystems in Malaysia; the marine, the wetlands and the tropical rainforest ecosystem.
5.         The stress factors are the disruptive causes of the ecosystems equilibrium.
6.         The ecosystem imbalance caused by the human activities has lead to biodiversity declining in the ecosystem.
7.         The impacts of biodiversity decline are species extinction, endangered species and threatened species.
8.         Measures should be taken to prevent biodiversity from declining in the ecosystem.
9.         Means of conservation include the protection, management and renewal of natural resources.
10.     Aims of conservation are to preserve biodiversity, provide food and other natural resources, balance of oxygen and carbon dioxide, preserve water and catchments areas.






Chapter 16     Biotic Resources

1.         Biotic resources are organisms that provide raw materials for agriculture, medicine, construction, nutrition and many more.
2.         In agriculture, food crops and marine are the main biotic resources. They can be modified into high yield producers, biological pest control and pollinators.
3.         In the medicine sector, biotic resources can be manufactured into antibiotics.
4.         Traditional or alternative formulations include herbal health supplements.
5.         Mushrooms, seaweeds, raw vegetables and honey bees are examples of biotic resources providing valuable nutrients.
6.         Timber, rattan, and bamboos are biotic resources used for building constructions and furniture.
7.         Other uses of biotic resources are as ingredients in the catchment areas.
8.         Tropical forests provide fresh water trapped in the catchment areas.
9.         Water catchment is an area of land where water collects and drains into streams and rivers or lakes.
10.     The catchment areas provide environmental services such as provide fresh water, recycle water, store fresh water, flood regulator and prevent soil erosion.
11.     Destruction of water catchment will disrupt the water cycle, the supply of fresh water and it cause flood and landslides.
12.     Human activities like throwing rubbish into rivers, seas and streams add to the destruction of the catchment areas by.
13.     Human, animal and industrial waste can cause diseases, deformities and even death.
14.     Effects of development on tropical rainforest will cause loss of habitat, loss of carbon dioxides, CO2 sink, loss of biodiversity, loss of possible medicinal plants, soil erosion, water pollution and ecosystem destruction.
15.     Biotic resources are meant to be utilised but in a sustainable manner.


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Chapter 17     Balance in Ecosystem

1.         Changes in the flora and fauna within a community take place through ecological succession.
2.         Primary succession takes place where no community previously existed. It starts with soil building, often by lichens and other pioneer organisms. This is followed by grasses and mosses. Eventually this is replaced by more complex communities until climax state is reached.
3.         Secondary succession, the establishment of a new community where the previously community has been destroyed or disrupted, occurs more rapidly than primary succession.
4.         Causes of extinction including habitat loss, pollution, and over exploitation are now largely responsible for the loss of biodiversity.
5.         Conservation techniques involve habitat preservation and habitat restoration in order to maintain a stable and balanced ecosystem.