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    All Rights Reserved 2012 Ng Chee Kin

    Written By

    Ng Chee KinB.Sc.(Hons.), MBA

    [email protected]@blogspot.com.au

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    4 Hazard warning symbols:

    Highly flammable

    Examples:Ethanol, petrol

    Explosive

    Examples:Sodium, potassium

    Corrosive

    Examples:Concentratedhydrochloric acid,sodium hydroxide

    Poisonous/toxic

    Examples:Lead, mercury

    Irritant

    Examples:Chlorine, chloroform

    Highly flammable

    Examples:Ethanol, petrol

    1.3 The Steps in a Scientific Investigation

    (1) Identifying the problem

    (2) Forming a hypothesis

    (3) Planning the experiment

    (4) Controlling variables

    (5) Collecting data

    (6) Analysing and interpreting data

    (7) Drawing a conclusion

    (8) Writing a report

    1.4 Physical Quantities and Their Units

    1 Physical quantities and their s1 units:

    Physicalquantities

    SI unitsUnit

    symbols

    length metre m

    mass kilogram kg

    time second s

    temperature kelvin K

    electric current ampere A

    1.5 Weight and Mass

    1 The weight of an object is the pull of theEarths gravity on the object.

    2 The mass of an object is the quantity of matterin the object.

    1.6 Measuring Tools

    Physicalquantity

    Tools/methodUnits

    and theirrelationship

    Length ofstraight lines

    Metre rule,ruler, calipers(internal &

    1 cm = 10 mm1 m = 100 cm1 km = 1000 m

    external),micrometer,verniercalipers

    Length of

    curves

    String

    and ruler,opisometer

    Area ofregularshapes

    Mathematicalformulae,graph paper

    1 cm2= 100 mm2

    1 m2= 10 000 cm2

    1 km2= 1 000 000 m2

    Area ofirregularshapes

    Estimationusing graphpaper

    Volume of

    liquids

    Measuring

    cylinder,pipette,burette

    1 ml= 1 cm3

    1 l= 1 000 cm3

    1 m3= 1 000 000 cm3

    Volume ofregular-shaped solids

    Mathematicalformulae,waterdisplacementmethod(Eureka canor measuring

    cylinder filledwith water) 1 m3= 1 000 000 cm3

    Volume ofirregular-shaped solids

    Waterdisplacementmethod(usingEureka canor measuringcylinder filledwith water)

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    1.7 The Importance of Standard Units

    1 Standard unit improves internationalcommunications.

    2 They also ensure the physical quantities aremeasured accurately and consistently.

    CHAPTER 2

    Cell As a Unit of Life

    2.1 What is a Cell?

    1 A cell is the basic unit of life. 2 Its function is to carry out life processes.

    Protoplasm Cell membrane

    Nucleus Cytoplasm

    Cell

    Animal cells Plant cells

    Irregular in shape Regular in shape

    No cell wall Have cell wall

    No chloroplasts Have chloroplasts

    Mostly no vacuoles Have large vacuoles

    3 The functions of cell structures:

    Structure Function

    Nucleus Controls all cell activities

    Cytoplasm A place where chemicalprocesses take place

    Cell membrane Controls flow of materialsin and out of cell

    Cell wall Gives shape to the cell

    (e)

    (f)

    2 A multicellular organism has many cells. (a) (b)

    (c)

    2.3 Cell Organisation in the Human Body

    1 Organisation of cell:

    Cell (simple)

    Tissue

    Organ

    System

    Organism (complex)

    nucleus

    Chloroplast Carries outphotosynthesis

    Vacuoles Stores water anddissolved materials

    4 A microscope is used to study the general

    structure of a cell.

    2.2 Unicellular and Multicellular Organisms

    1 A unicellular organism has one cell only.

    (a)

    (b)

    (c)

    (d)

    Pleurococcus

    Amoebapseudopodium

    nucleus

    Chlamydomonas

    Paramecium

    chloroplast

    cilium

    Euglena

    Yeast

    nucleus

    bud

    Chondrus

    Hydra

    Spirogyra

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    2 Examples of cell: (a) Nerve cell

    (b) Red blood cell

    (c) Epithelial cell

    (d) Bone cell

    3 Examples of tissue: (a) Connective tissue

    (b) Mucsle tissue

    (c) Nerve tissue

    (d) Epithelial tissue

    4 Examples of system:

    (a) (b)

    (c) (d)

    (e) (f)

    BrainTongue

    KidneyEye

    StomachLungs

    5 Examples of system:

    2.4 The Human Being A Complex Organism

    1 A human being is a complex multicellularorganism because the cells are organized intotissues, organs and systems.

    2 Cell specialisation helps to divide bodyfunctions among the different types of cells.

    3 Cell specialisation and cell organisationensure the life processes are carried outeffectively.

    Pituitarygland

    Testis(male)

    Ovary(female)

    Adrenalgland

    Thyroidgland

    Female

    Oviduct orFallopian tube

    Ovary

    UterusVagina

    Male

    Spermduct

    Urethra

    penis

    Testis

    Sexglands

    Endocrine system

    Nose

    Trachea Bronchus

    Lungs

    Skin

    Liver

    Kidney

    Urinarybladder

    Respiratory system Excretory system

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    CHAPTER 3

    Matter

    3.1 What is Matter?

    1 Matter is everything that has mass and

    occupies space. 2 Examples of matter are wood, air, water, soiland living things.

    3.2 The States of Matter

    1 Matter exists in three states: solid, liquidandgas.

    2 Matter changes its state when it is heated orcooled.

    3 The kinetic theory of matterstates that matterconsists of tinyand discreteparticles.

    4 Characteristics of state matter:Characteristic Solid Liquid Gas

    Arrangementof particles

    Closelypacked

    Further apart Very farapart

    Spacesbetweenparticles

    Very small Large Very large

    Movement ofparticles

    No freemovement,vibrateabout a fixedposition

    Move freely,collide withone another

    Movefreely, veryrapidly andrandomly

    Density High Medium Low

    Shape Definiteshape

    No definiteshape

    No definiteshape

    Volume Definitevolume

    Definitevolume

    No definitevolume

    Examples Soil, wood,most metals

    Water,mercury(a type ofmetal)

    Air

    3.3 The Concept of Density

    1 Densityis defined as mass per unit volume ofa substance.

    MassDensity =

    Volume

    2 The unit of density is gram per cubiccentimeter (g/cm3).

    3 The buoyancy of a substance is affected by itsdensity.

    4 Buoyancy (or flotation) refers to the abilityof a substance to float or sink in another

    substance. 5 A lower density substance will float on a

    higher density liquid. 6 On the other hand, a higher density substance

    will sink in a lower density liquid.

    3.4 The Properties of Matter and Their Applicationin Everyday Life

    Matter Example Applications

    Solid Iron, steel To construct buildings,bridges and vehicles,make cooking utensils

    Wood To build bridges adhouses, making furniture

    Plastic To make toys, componentsin vehicles

    Liquid Mercury To make thermometer,hydrometer

    Water To make drinks, cooking,washing and cleaning

    Gas Air To fill buoy, rise hotair balloons, make asubmarine sink or float

    CHAPTER 4

    The Variety of Resources on Earth

    4.1 The Various Resources on Earth

    1 The basic resources needed for life on Earthare:

    Basic

    resource

    ImportanceUseful

    substancesAir Needed for

    respiration andcombustion

    Oxygen,nitrogen,carbondioxide

    Carbon dioxideis needed forphotosynthesis

    Water Needed to supportthe functions of thebody systems

    Fresh water

    Soil Contains air, water,minerals and organicsubstances which areneeded to supportliving things

    Humus

    Minerals Minerals such asmetals are usedto make usefulproducts andconstruct buildings

    Metals

    water (1.00 g/cm3)

    zinc (7.10 g/cm3)

    cork (0.24 g/cm3)

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    Fossilfuels

    Used to produceenergy in powerplants, factories,vehicles, machinesand to make plastics

    Coal,petroleum,natural gases

    Living

    things

    They are sources

    of food, buildingmaterials, clothesand fuel

    Meat, skin,

    carcasses,silk, milk

    4.2 Elements, Compounds and Mixtures

    Comparing elements, compounds and mixtures

    Aspect Element Compound Mixture

    Appearance

    Definition It is thesimplessubstance

    It is madeup of twoor moresubstanceswhich arechemicallycombined

    It is madeup of twoor moresubstanceswhichare notchemicallycombined

    Composition Only

    consists ofone typeof particle

    Can consist

    of one ormore thanone type ofparticle

    Separationmethod

    Cannot beseparated

    by anyprocesses

    Can beseparated

    by chemica lmeans only,such aselectrolysis

    Can beseparated

    byphysicalmeans,such asfiltration

    Examples Iron,hydrogen,oxygen,helium,carbon,mercury

    Naphthalene,sugar, rubber,table salt,water

    Soil, air,dessert

    Comparing metals and non-metals

    Physicalproperties

    Metals Non-metals

    Surfaceappearance

    Shiny Dull

    Brittlenessand hardness

    Ductile (canbe pulled intostrands) andhard

    Brittle (canbreak easily)and soft

    Malleability(ability to beshaped)

    Malleable Non-malleable

    Conductivityof heat

    Goodconductor ofheat

    Poorconductor ofheat

    Conductivityof electricity

    Goodconductor ofelectricity

    Poorconductor ofelectricity

    Melting point High LowBoiling point High Low

    Density High Low

    Physical methods to separate components of a mixture

    Physicalproperties

    Metals Non-metals

    Surfaceappearance

    Shiny Dull

    Brittleness andhardness

    Ductile (canbe pulledinto strands)and hard

    Brittle (canbreak easily)and soft

    Malleability(ability to be

    shaped)

    Malleable Non-malleable

    Conductivity ofheat

    Goodconductor ofheat

    Poorconductor ofheat

    Conductivity ofelectricity

    Goodconductor ofelectricity

    Poorconductor ofelectricity

    Melting point High Low

    Boiling point High Low

    Density High Low

    Comparing the Properties of Compounds andMixtures

    Aspect Compounds Mixtures

    (a) Method ofseparation

    By chemicalreactions.

    By physicalmeans.

    (b) Formationof a newsubstance

    A newsubstance isformed

    No newsubstance isformed

    (c) Conversion of

    energy

    Heat is

    released orabsorbedwhen acompound isformed

    No heat is

    released orabsorbedwhen amixture isformed

    (d) Characteristicof the originalcomponents

    Thecharacteristicsof the originalcomponentsare no longermaintained

    Thecharacteristicsof the originalcomponentsaremaintained

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    (e) Identificationof the originalcomponents

    The originalcomponentscannot beidentifiedeasily

    The originalcomponentscan beidentifiedeasily

    (f) Ratio of

    components

    Components

    are combinedin a specificratio

    Components

    are formedwithout afixed ratio

    4.3 To Appreciate the Importance of EarthsResources

    1 Preservationof resources is the act of keepingthe resources in their original state.

    2 Conservationof resources is the responsibleuse and management of natural resources toprevent loss, waste or damage.

    3 Preservation and conservation of Earthsresources are important to:(a) prevent extinction of animal and plant

    species(b) prevent depletion of natural resources

    such as fossil fuels and minerals(c) prevent the pollution of air and water(d) ensure the basic needs of humans are not

    threatened(e) ensure the natural resources will be

    available for future generations

    CHAPTER 5

    The Air Aroun Us

    5.1 The Composition of Air

    Nitrogen (78%) Oxygen (21%)

    Inert gases + watervapour + dust +microorganisms (0.97%)

    Carbon dioxide(0.03%)

    Experiments to show the properties of air

    1 Air consists of about 20% of oxygen.

    Water fills up ofgas jar, showingthat about 20% ofthe volume of airconsists of oxygen

    2 Air contains water vapour.

    Beginning ofexperiment

    End ofexperiment

    Cork

    Test tube

    Ice

    Water

    Liquid on theouter wall ofthe test tube

    3 Air contains microorganisms.

    4 Air contains dust particles.

    Glass slide

    Sticky surfacefacing upDust particles

    Glass slide

    Dustparticles

    5.2 The Properties of Oxygen and Carbon Dioxide

    Properties OxygenCarbondioxide

    Colour Colourless Colourless

    Odour (smell) Odourless Odourless

    Solubility inwater

    Slightlysoluble

    Slightlysoluble

    Solubilityin sodiumhydroxide

    Not soluble Very soluble(to formsodiumcarbonate)

    Effect on limewater

    No effect Lime waterturns cloudy

    Supporting

    combustion

    Supports

    combustion.

    A glowingsplinterrelights

    A burningsplinterburns morebrightly

    Does not

    supportcombustion. A glowing

    splinterrelights

    A burningsplinterburns morebrightly

    pH Neutral

    Has noeffect onmoist blueand redlitmuspapers

    Has noeffect onhydrogencarbonateindicator

    Acidic

    Turnsmoist bluelitmuspaper tored

    Turns redhydrogencarbonateindicator toyellow

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    5.3 Oxygen is Needed for Respiration

    1 Oxygen is needed for respiration to produceenergy.

    2 The composition of inhaled and exhaled air:

    GasComposition (%)

    Inhaled air Exhaled airNitrogen 78 78

    Oxygen 21 16

    Carbondioxide

    0.03 4

    Inert gases 0.97 0.97

    Watervapour

    Less More

    5.4 Oxygen is Needed for Combustion

    1 Combustion is a process that requires oxygen,heatand fuel.

    2 Combustion of carbon (such as charcoal):

    Carbon + Oxygen Carbon dioxide3 Combustion of hydrocarbon (such as

    kerosene):

    Hydrocarbon + Oxygen Carbon dioxide + Water

    5.5 Air Pollution

    1 Air pollution is caused by the pollutants inthe air.

    2 Air pollutants are harmful substances thatare added to the air.

    3 The effects of air pollution on human beings: Lung cancers (caused by asbestos,

    sulphur dioxide) Brain damage in children (caused by lead

    particles, carbon monoxide)

    Bronchitis, pneumonia (caused bysulphur dioxide)

    Death (caused by carbon monoxide) 4 The effects of air pollution on the

    environment: Acid rain (caused by sulphur dioxide) Thinning of the ozone layer (caused by

    CFC) Greenhouse effect (caused by carbon

    dioxide) Haze (caused by dust particles, soot)

    5.6 The Importance of Keeping the Air Clean

    1 We can keep the air clean by practising thefollowing:

    Using less CFC based products, such asaerosols.

    Recycling and reducing wastes Using unleaded petrol

    Using public transport or sharing vehicles(car pooling)

    Installing catalytic converters to motorvehicles

    2 Cigarette smoke contains tar, nicotine andcarbon monoxide which are harmful tohumans.

    CHAPTER 6

    Sources of Energy

    6.1 The Various Forms and Sources of Energy

    1 Energy is an ability to do work.

    2 The SI unit for energy is joule(J).

    3 Forms of energy: Potential, electrical, kinetic,chemical, heat, nuclear, light, mechanical,sound

    Energy Characteristics Examples

    Potential(stored energy)

    Energy storedin an object dueto its position orcondition.

    A stretchedsling-shot

    A rock on acliff

    A

    compressedspring

    A wound upalarm clock

    Kinetic(workingenergy)

    Energy thatis foundin movingobjects.

    A movingbus

    A swingingpendulum

    A rotatingceiling fan

    A flyingaeroplane

    Heat(workingenergy)

    Energy thatis released

    by hotobjects.

    A burningcandle

    A boilingwater

    The hot Sun A hot iron

    Light(workingenergy)

    Energy thatis produced

    by glowing

    objects.

    A shiningstar

    A glowing

    light bulb A burning

    campfire A switched

    on torch

    Sound(workingenergy)

    Energy thatis produced

    by vibratingobjects.

    A beatingdrum

    A personsinging

    A blowingwhistle

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    A ringingtelephone

    Electrical(workingenergy)

    Energy thatis produced

    by flowing

    electricalcurrent(electricity).

    An electriciron

    An electric

    heater

    Chemical(stored energy)

    Energy thatis stored ina substancethat can be

    burnt.

    Food Fossil fuels

    (such asnatural gas,coal andpetrol)

    Wood

    Nuclear(stored energy)

    Energy thatis produced

    by atomsthat are

    brokendown(throughnuclearfission) orcombined(throughnuclearfusion).

    Explosionof an atomic

    bomb The

    explosionon the Sunssurface

    Mechanical(combinationof workingand storedenergy)

    Energy thatis posessed

    by an objectthat has

    both kineticenergy andpotentialenergy.

    A car isdriven up ahill

    A pendulumswings backand forth

    4 Sources of energy:

    Sources ofenergy

    Examples Uses

    Fossi l fue ls Coal Petroleum Natural

    gas

    To generateelectricity inpower plants

    As the mainfuel for vehiclesand machines

    Wind Movingair

    To move asailboat

    To turn awindmill forpumping waterand grind corn

    To generate

    electricity inwind farms

    Water(hydro)

    Rain fall To generatehydroelectricity

    Sun(solar)

    The Su n To generateelectricity (solarcells and solarpanels collectsolar energyand convertit electrical

    energy) To enable

    photosynthesisin green plants.

    Radioactivesubstances

    Uranium Plutonium

    To producenuclear energy.

    To produceelectrical energyin submarinesand warships

    Geothermal Geysers Hot

    springs Volcanoes

    To producegeothermalenergy thatcan be usedto generateelectricity

    5 Energy changes from one form to another. For

    example:

    Situation Energy change

    A marble rollsdown a slope

    Potential energyKinetic energy

    Winding up springof a toy car

    Kinetic energyPotential energy

    Burning a candle Chemical energyHeat + Light energy

    Beating a drum Kinetic energySound energy

    Switching on a fan Electrical energykinetic energy

    An explodingatomic bomb

    Nuclear energyHeat + Light +Sound energy

    6 The Sun is the primary source of energy.

    6.2 Renewable and Non-Renewable Energy

    Sources 1 Comparing renewable and non-renewable

    energy sources:

    Renewable Energy(energy sources thatcan be reused andwill never run out)

    Non-renewable Energy(energy sources that willbe used up one day andcannot be replaced)

    Solar energy(from the Sun)

    Fossil fuels (suchas natural gas,petroleum and coal)

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    Hydroelectricity(from flowingwater)

    Biomass energy(from plants)

    Wind energy

    (from wind) Geothermalenergy (from theEarth)

    Nuclear energy(from plutonium)

    2 Conservation and efficient use of energy:(a) Use energy efficient equipment, such as

    fluorescent lights(b) Use public transport, such as buses and

    light-rail transit (LRT)(c) Practice car-pooling to work

    6.3 The Importance of Conserving Energy Sources

    1 Conserving non-renewable resourceswill make them last longer for the futuregenerations.

    CHAPTER 7

    Heat

    7.1 Heat as a Form of Energy

    1 Heat is a form of energy 2 Heat can be produced from:

    (a) kinetic energy, such as rubbing twoobjects together

    (b) chemical energy, such as burning fossilfuels

    (c) electrical energy, such as lighting anelectric bulb

    (d) nuclear energy, such as nuclear fission inthe Sun

    3 Comparing heat and temperature:

    Aspect Heat Temperature

    Definitionon

    A form ofenergy

    Degree ofhotness of anobject

    SI Unit joule (J) kelvin (K).Normally we

    use degreesCelsius (C)

    How it isproduced

    Kineticenergy(such asrubbinghands)

    Chemicalenergy(such asburning

    fossil fuels) Electrical

    energy(such aslighting alight bulb)

    Nuclearenergy(such asnuclearfission in

    the Sun)

    Supplyingheat energyto an object(causingtemperatureto increase)

    Removingheat froman object

    (causingtemperatureto decrease)

    Effect Causesmatter toexpand orcontract

    Caussmatter tochangefrom onestate toanother

    Causesmatter tobecome hotor cold

    Causesheat to flowfrom a hotregion to acold region

    Affected by Volume-the biggerthevolume,the morethe heat

    Amount ofheat- themore the heatenergy issupplied, thehigher the

    temperatureDifference

    P containsmore heatthan Q

    P and Q havethe sametemperature

    7.2 The Effects of Heat Flow on Matter

    1 Heat changes the volume of matter. 2 When heated, the volume of matter increases.

    Hence, matter expands. 3 When cooled, the volume of matter decreases.

    Hence, matter contracts. 4 Heat flows from a hot region to a cold region

    in three ways:(a) conduction, occurs in solids(b) convection, occurs in fluids (such as

    liquids and gases)(c) radiation, does not require a medium

    7.3 Effects of Heat on Matter

    ProcessChange of state

    of matterHeat flow

    Melting SolidLiquid Heat isabsorbed

    Freezing LiquidS olid Heat isreleased

    P Q P Q

    100C100C

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    Boiling LiquidGas Heat isabsorbed

    Condensation Gasliquid Heat isreleased

    Evaporation LiquidGas Heat isabsorbed

    Sublimation SolidGas

    Gas Solid Heat isabsorbedHeat isreleased

    7.4 Application of Contraction and Expansion of

    Matter

    1 Application of expansion and contraction ofmatter:

    (a) Mercury or alcohol in thermometers (b) Bimetallic strip in thermostats (c) Bimetallic strip in fire alarms (d) Gaps in railway tracks and bridges (e) Telephone wires (f) Metal pipes carrying hot water and oil

    7.5 Absorbing and Giving Out Heat

    1 Objects that absorb heat are called heatabsorber.

    2 Objects that give out heat are called heatradiator.

    3 Dark, dull objects are good heat absorber andgood heat radiator.

    4 White, shiny surfaces are poor heat absorberand poor heat radiator.

    7.6 The Benefits of Heat Flow

    1 Application of heat flow via conduction:(a) Heat is used for cooking food with

    cooking utencil(b) Heat is used to melt metal for making

    jewellery and equipment

    2. Applications of heat flow via convection:(a) Convection currents improve the aircirculation and keeps the buildings cool

    (b) Convection currents cool the Earthssurface through sea breeze and landbreeze.

    3 Applications of heat flow via radiation:(a) Heat flow by radiation is used to dry

    laundry(b) The heat from the Sun keeps the Earth

    and our body warm

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