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Written By

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

ngcheekin@gmail.commrcheekin@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

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)

Thyroidgland

Female

Oviduct orFallopian tube

Ovary

UterusVagina

Male

Spermduct

Urethra

penis

Testis

Sexglands

Endocrine system

Nose

Trachea Bronchus

Lungs

Skin

Liver

Kidney

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

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 ofe