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Page 1: Express Notes - Science Form 1

All Rights Reserved ©2012 Ng Chee Kin

Written By Ng Chee Kin

B.Sc.(Hons.), MBA [email protected]

[email protected]

Page 2: Express Notes - Science Form 1

CHAPTER 1Introduction to Science

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1.1 What is Science?

1 Science is a systematic study of nature and its effects on us and the environment.

2 Natural phenomena are events that happen naturally around us.

3 Science can be divided into many fields such as: Biology, physics, chemistry, geology, astronomy and meteorology.

4 Science-based careers are occupations that are based on science, for example: Life science – doctor, nurse, dietician, botanist, zookeeper; earth science – environmental scientist, meteorologist, geologist, mineralogist, volcanologist; and physical science – physicist, chemist, engineer, architect, and radiologist.

1.2 A Science Laboratory

1 It is a room or a building where scientific investigations are carried out.

2 We must obey safety rules and precautions when working in a science laboratory.

3 Common laboratory apparatus:

Test-tube Boiling tube

Beaker Filter funnel

Bell jar Gas jar

Flat-bottomed flask Round-bottomed flask

Flat-bottomed flask Conical flask

Measuring cylinder

Water trough Tripod stand

Evaporating dish

Test tube rack

Test tube holder Crucible tongs

Dropper Eureka can

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4 Hazard warning symbols:

Highly flammable

Examples:Ethanol, petrol

Explosive

Examples:Sodium, potassium

Corrosive

Examples:Concentrated hydrochloric 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:

Physical quantities

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 the Earth’s gravity on the object.

2 The mass of an object is the quantity of matter in the object.

1.6 Measuring Tools

Physical quantity

Tools/methodUnits

and their relationship

Length of straight lines

Metre rule, ruler, calipers (internal &

1 cm = 10 mm 1 m = 100 cm 1 km = 1000 m

external), micrometer, vernier calipers

Length of curves

String and ruler, opisometer

Area of regular shapes

Mathematical formulae, graph paper

1 cm2 = 100 mm2

1 m2 = 10 000 cm2

1 km2 = 1 000 000 m2

Area of irregular shapes

Estimation using graph paper

Volume of liquids

Measuring cylinder, pipette, burette

1 ml = 1 cm3

1 l = 1 000 cm3

1 m3 = 1 000 000 cm3

Volume of regular-shaped solids

Mathematical formulae, water displacement method (Eureka can or measuring cylinder filled with water) 1 m3

= 1 000 000 cm3

Volume of irregular-shaped solids

Water displacement method (using Eureka can or measuring cylinder filled with water)

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1.7 The Importance of Standard Units

1 Standard unit improves international communications.

2 They also ensure the physical quantities are measured accurately and consistently.

CHAPTER 2Cell 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 chemical processes take place

Cell membrane Controls flow of materials in 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 out photosynthesis

Vacuoles Stores water and dissolved 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 multicellular organism because the cells are organized into tissues, organs and systems.

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

3 Cell specialisation and cell organisation ensure the life processes are carried out effectively.

Pituitarygland

Testis(male)

Ovary(female)

Adrenalgland

Thyroidgland

Female

Oviduct orFallopian tube

OvaryUterus

Vagina

Male

Spermduct

Urethra

penis

Testis

Sex glands

Endocrine system

Nose

Trachea Bronchus

Lungs

Skin

Liver

Kidney

Urinarybladder

Respiratory system Excretory system

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CHAPTER 3Matter

3.1 What is Matter?

1 Matter is everything that has mass and occupies space.

2 Examples of matter are wood, air, water, soil and living things.

3.2 The States of Matter

1 Matter exists in three states: solid, liquid and gas.

2 Matter changes its state when it is heated or cooled.

3 The kinetic theory of matter states that matter consists of tiny and discrete particles.

4 Characteristics of state matter:

Characteristic Solid Liquid Gas

Arrangement of particles

Closely packed

Further apart Very far apart

Spaces between particles

Very small Large Very large

Movement of particles

No free movement, vibrate about a fixed position

Move freely, collide with one another

Move freely, very rapidly and randomly

Density High Medium Low

Shape Definite shape

No definite shape

No definite shape

Volume Definite volume

Definite volume

No definite volume

Examples Soil, wood, most metals

Water, mercury (a type of metal)

Air

3.3 The Concept of Density

1 Density is defined as mass per unit volume of a substance.

MassDensity = ————

Volume

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

3 The buoyancy of a substance is affected by its density.

4 Buoyancy (or flotation) refers to the ability of 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 Application in Everyday Life

Matter Example Applications

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

Wood To build bridges ad houses, making furniture

Plastic To make toys, components in vehicles

Liquid Mercury To make thermometer, hydrometer

Water To make drinks, cooking, washing and cleaning

Gas Air To fill buoy, rise hot air balloons, make a submarine sink or float

CHAPTER 4The Variety of Resources on Earth

4.1 The Various Resources on Earth

1 The basic resources needed for life on Earth are:

Basic resource

ImportanceUseful

substances

Air Needed for respiration and combustion

Oxygen, nitrogen, carbon dioxide

Carbon dioxide is needed for photosynthesis

Water Needed to support the functions of the body systems

Fresh water

Soil Contains air, water, minerals and organic substances which are needed to support living things

Humus

Minerals Minerals such as metals are used to make useful products and construct buildings

Metals

water (1.00 g/cm3)

zinc (7.10 g/cm3)

cork (0.24 g/cm3)

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Fossil fuels

Used to produce energy in power plants, factories, vehicles, machines and to make plastics

Coal, petroleum, natural gases

Living things

They are sources of food, building materials, clothes and 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 the simples substance

It is made up of two or more substances which are chemically combined

It is made up of two or more substances which are not chemically combined

Composition Only consists of one type of particle

Can consist of one or more than one type of particle

Separation method

Cannot be separated by any processes

Can be separated by chemical means only, such as electrolysis

Can be separated by physical means, such as filtration

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

Naphthalene, sugar, rubber, table salt, water

Soil, air, dessert

Comparing metals and non-metals

Physical properties

Metals Non-metals

Surface appearance

Shiny Dull

Brittleness and hardness

Ductile (can be pulled into strands) and hard

Brittle (can break easily) and soft

Malleability (ability to be shaped)

Malleable Non-malleable

Conductivity of heat

Good conductor of heat

Poor conductor of heat

Conductivity of electricity

Good conductor of electricity

Poor conductor of electricity

Melting point High Low

Boiling point High Low

Density High Low Physical methods to separate components of a mixture

Physical properties

Metals Non-metals

Surface appearance

Shiny Dull

Brittleness and hardness

Ductile (can be pulled into strands) and hard

Brittle (can break easily) and soft

Malleability (ability to be shaped)

Malleable Non-malleable

Conductivity of heat

Good conductor of heat

Poor conductor of heat

Conductivity of electricity

Good conductor of electricity

Poor conductor of electricity

Melting point High Low

Boiling point High Low

Density High Low Comparing the Properties of Compounds and Mixtures

Aspect Compounds Mixtures

(a) Method of separation

By chemical reactions.

By physical means.

(b) Formation of a new substance

A new substance is formed

No new substance is formed

(c) Conversion of energy

Heat is released or absorbed when a compound is formed

No heat is released or absorbed when a mixture is formed

(d) Characteristic of the original components

The characteristics of the original components are no longer maintained

The characteristics of the original components are maintained

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(e) Identification of the original components

The original components cannot be identified easily

The original components can be identified easily

(f) Ratio of components

Components are combined in a specific ratio

Components are formed without a fixed ratio

4.3 To Appreciate the Importance of Earth’s

Resources

1 Preservation of resources is the act of keeping the resources in their original state.

2 Conservation of resources is the responsible use and management of natural resources to prevent loss, waste or damage.

3 Preservation and conservation of Earth’s resources 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 5The Air Aroun Us

5.1 The Composition of Air

Nitrogen (78%) Oxygen (21%)

Inert gases + water vapour + 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 – of gas jar, showing that about 20% of the volume of air consists of oxygen

2 Air contains water vapour.

Beginning of experiment

End of experiment

Cork

Test tube

Ice

Water

Liquid on the outer wall of the test tube

3 Air contains microorganisms.

4 Air contains dust particles.

Glass slide

Sticky surface facing upDust particles

Glass slide

Dust particles

5.2 The Properties of Oxygen and Carbon Dioxide

Properties OxygenCarbon dioxide

Colour Colourless Colourless

Odour (smell) Odourless Odourless

Solubility in water

Slightly soluble

Slightly soluble

Solubility in sodium hydroxide

Not soluble Very soluble (to form sodium carbonate)

Effect on lime water

No effect Lime water turns cloudy

Supporting combustion

Supports combustion.

• A glowing splinter relights

• A burning splinter burns more brightly

Does not support combustion.• A glowing

splinter relights

• A burning splinter burns more brightly

pH Neutral• Has no

effect on moist blue and red litmus papers

• Has no effect on hydrogen carbonate indicator

Acidic• Turns

moist blue litmus paper to red

• Turns red hydrogen carbonate indicator to yellow

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5.3 Oxygen is Needed for Respiration

1 Oxygen is needed for respiration to produce energy.

2 The composition of inhaled and exhaled air:

GasComposition (%)

Inhaled air Exhaled air

Nitrogen 78 78

Oxygen 21 16

Carbon dioxide

0.03 4

Inert gases 0.97 0.97

Water vapour

Less More

5.4 Oxygen is Needed for Combustion

1 Combustion is a process that requires oxygen, heat and fuel.

2 Combustion of carbon (such as charcoal):

Carbon + Oxygen → Carbon dioxide 3 Combustion of hydrocarbon (such as

kerosene):

Hydrocarbon + Oxygen → Carbon dioxide + Water

5.5 Air Pollution

1 Air pollution is caused by the pollutants in the air.

2 Air pollutants are harmful substances that are 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 by sulphur 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 the following:• Using less CFC based products, such as

aerosols.• Recycling and reducing wastes• Using unleaded petrol• Using public transport or sharing vehicles

(car pooling)• Installing catalytic converters to motor

vehicles 2 Cigarette smoke contains tar, nicotine and

carbon monoxide which are harmful to humans.

CHAPTER 6Sources 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 stored in an object due to its position or condition.

• A stretched sling-shot

• A rock on a cliff

• A compressed spring

• A wound up alarm clock

Kinetic (working energy)

• Energy that is found in moving objects.

• A moving bus

• A swinging pendulum

• A rotating ceiling fan

• A flying aeroplane

Heat(working energy)

• Energy that is released by hot objects.

• A burning candle

• A boiling water

• The hot Sun• A hot iron

Light(working energy)

• Energy that is produced by glowing objects.

• A shining star

• A glowing light bulb

• A burning campfire

• A switched on torch

Sound (working energy)

• Energy that is produced by vibrating objects.

• A beating drum

• A person singing

• A blowing whistle

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• A ringing telephone

Electrical(working energy)

• Energy that is produced by flowing electrical current (electricity).

• An electric iron

• An electric heater

Chemical(stored energy)

• Energy that is stored in a substance that can be burnt.

• Food• Fossil fuels

(such as natural gas, coal and petrol)

• Wood

Nuclear(stored energy)

• Energy that is produced by atoms that are broken down (through nuclear fission) or combined (through nuclear fusion).

• Explosion of an atomic bomb

• The explosion on the Sun’s surface

Mechanical(combination of working and stored energy)

• Energy that is posessed by an object that has both kinetic energy and potential energy.

• A car is driven up a hill

• A pendulum swings back and forth

4 Sources of energy:

Sources of energy

Examples Uses

Fossil fuels • Coal• Petroleum• Natural

gas

• To generate electricity in power plants

• As the main fuel for vehicles and machines

Wind • Moving air

• To move a sailboat

• To turn a windmill for pumping water and grind corn

• To generate electricity in wind farms

Water (hydro)

• Rain fall • To generate hydroelectricity

Sun (solar)

• The Sun • To generate electricity (solar cells and solar panels collect solar energy and convert it electrical energy)

• To enable photosynthesis in green plants.

Radioactive substances

• Uranium• Plutonium

• To produce nuclear energy.

• To produce electrical energy in submarines and warships

Geothermal • Geysers• Hot

springs• Volcanoes

• To produce geothermal energy that can be used to generate electricity

5 Energy changes from one form to another. For

example:

Situation Energy change

A marble rolls down a slope

Potential energy → Kinetic energy

Winding up spring of a toy car

Kinetic energy → Potential energy

Burning a candle Chemical energy →Heat + Light energy

Beating a drum Kinetic energy → Sound energy

Switching on a fan Electrical energy → kinetic energy

An exploding atomic bomb

Nuclear energy → Heat + 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 that can be reused and will never run out)

Non-renewable Energy(energy sources that will be used up one day and cannot be replaced)

• Solar energy (from the Sun)

• Fossil fuels (such as natural gas, petroleum and coal)

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• Hydroelectricity (from flowing water)

• Biomass energy (from plants)

• Wind energy (from wind)

• Geothermal energy (from the Earth)

• 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 resources will make them last longer for the future generations.

CHAPTER 7Heat

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 two objects together

(b) chemical energy, such as burning fossil fuels

(c) electrical energy, such as lighting an electric bulb

(d) nuclear energy, such as nuclear fission in the Sun

3 Comparing heat and temperature:

Aspect Heat Temperature

Definition on

A form of energy

Degree of hotness of an object

SI Unit joule (J) kelvin (K). Normally we use degrees Celsius (°C)

How it is produced

• Kinetic energy (such as rubbing hands)

• Chemical energy (such as burning fossil fuels)

• Electrical energy (such as lighting a light bulb)

• Nuclear energy (such as nuclear fission in the Sun)

• Supplying heat energy to an object (causing temperature to increase)

• Removing heat from an object (causing temperature to decrease)

Effect • Causes matter to expand or contract

• Causs matter to change from one state to another

• Causes matter to become hot or cold

• Causes heat to flow from a hot region to a cold region

Affected by • Volume- the bigger the volume, the more the heat

• Amount of heat- the more the heat energy is supplied, the higher the temperature

Difference

P contains more heat than Q

P and Q have the same temperature

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 Solid → Liquid Heat is absorbed

Freezing Liquid → Solid Heat is released

P Q P Q

100°C100°C

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Boiling Liquid → Gas Heat is absorbed

Condensation Gas → liquid Heat is released

Evaporation Liquid → Gas Heat is absorbed

Sublimation Solid → Gas

Gas → Solid Heat is absorbedHeat is released

7.4 Application of Contraction and Expansion of Matter

1 Application of expansion and contraction of matter:

(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 heat absorber.

2 Objects that give out heat are called heat radiator.

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

4 White, shiny surfaces are poor heat absorber and 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 equipment2. Applications of heat flow via convection:

(a) Convection currents improve the air circulation and keeps the buildings cool

(b) Convection currents cool the Earth’s surface through sea breeze and land breeze.

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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