Focus Smart Science M1 (New Edition)

iv Science Mathayom 1

Chapter 1 Introduction to Science 11.1 What is Science? 21.2 Science Laboratory 31.3 Steps in Scientific Investigation 61.4 Physical Quantities and their Units 91.5 The Concept of Mass 101.6 Measuring Tools 111.7 The Importance of Standard Units 15Mastery Practice 17

Chapter 2 Cell as a Unit of Life 212.1 Understanding Cells 222.2 Unicellular and Multicellular Organisms 272.3 Cell Organisation in the Human Body 282.4 Diffusion and Osmosis in Cells 33Mastery Practice 36

Chapter 3 Plants 403.1 Photosynthesis 413.2 The Transport System in Plants 453.3 The Sexual Reproductive System of Flowering Plants 493.4 Pollination 503.5 The Development of Fruits and Seeds in Plants 523.6 The Germination of Seeds 543.7 Application of Vegetative Reproduction in Flowering Plants 563.8 Stimuli and Responses in Plants 573.9 Biotechnology 61Mastery Practice 65

Chapter 4 The World through Our Senses 694.1 Sensory Organs 704.2 Sense of Touch 724.3 Sense of Smell 744.4 Sense of Taste 744.5 Sense of Hearing 764.6 Sense of Sight 78Mastery Practice 82

Contents v

Chapter 5 Matter 855.1 Matter 865.2 Properties of Matter 885.3 States of Matter 895.4 Classification of Matter 94Mastery Practice 95

Chapter 6 Simple Machine 986.1 Lever 996.2 Appreciating Innovative Efforts in the Design of Machines to Simplify Work 102Mastery Practice 104

Chapter 7 Sources of Energy 1067.1 The Various Forms and Sources of Energy 1077.2 Renewable and Non-renewable Energy Sources 1137.3 The Importance of Conserving Energy Resources 117Mastery Practice 120

Chapter 8 Weather 1248.1 What is Weather? 1258.2 Factors of Weather 1258.3 Cloud Formation and Types of Cloud 1268.4 Measuring Rainfall 1288.5 Monsoons, Tropical Cyclones and Thunderstorms 1298.6 How to Avoid Danger during Severe Weather 1308.7 Interpreting Weather Forecasts and Their I mportance 130Mastery Practice 133

Chapter 9 Global Warming 1359.1 Global Warming 1369.2 Causes of Global Warming 1369.3 The Effects of Global Warming 137Mastery Practice 139

Chapter 1 Introduction to Science 1Chapter 1 Introduction to Science 1Chapter 1 Introduction to Science 1

By the end of this chapter, you should be able to

• understand what science is.

• name the common laboratory apparatus and their uses.

• explain the hazard warning symbols.

• observe the steps in a scientific investigation.

• understand the typical quantities and their units.

• understand the concepts of mass

• know how to use measuring tools.

Introduction to Science

1

What is Science?

2 Science Mathayom 1 Chapter 1 Introduction to Science 3

What is Science?1.1

We see various natural phenomena in our daily life. Natural phenomena are things that happen in nature.

Lightning, rainbows, the melting of ice, the growth of a baby into an adult and the fall of a ball to the ground are a few examples of natural phenomena. We want to know why and how all these things happen. We search for answers. The study of science gives us the answers.

Science is the systematic study of nature and how it affects us and our environment. The information produced from the study of science is known as scientific knowledge. Scientific knowledge develops as new scientific discoveries are discovered every day.

Using scientific knowledge, we invent many useful devices such as light bulbs, telephones and computers. The application of scientific knowledge for the use of mankind is called technology. We use technology in almost every aspect of life thus, making science part of our everyday life.

Importance of science

Science plays important roles in our daily life. Here are some examples:(a) Science helps us to understand ourselves. Knowing how our body works,

helps us to take better care of our health.(b) Science also helps us to understand our environment. This helps us

to improve the quality of our environment and conserve it for our future generation.

(c) Science makes our life more comfortable. We invent various machines to help us to work faster and more efficiently.


The figure below briefly describes how science benefits us in various fields.

In homes

• Facilities such as electricity and tap watermakelifeeasierandmorecomfortable.

• Various appliances such as washingmachine, microwave oven and vacuumcleanerhelpustodoourhouseworkfaster.

Communication

• Communicationiseasierandfasterwiththeuse of television, telephone,mobile phone,facsimileandcomputer.

• Global communication isnowpossiblewiththe use of communication satellites, e-mailandtheInternet.

Transportation

• Transportation is easier, faster and morecomfortable.

• Modern public transport such as commutertrainsandlightrailtransitreducecongestionincities.

• The design of better roads and highwaysincreasesthesafetyofusers.

Construction

• Buildings and structures are now built withstrongmaterialssuchassteel,concreteandreinforcedglass.

• Powerful machinery such as cranes,tractors and bulldozers are usually used inconstructionwork.

Agriculture

• Machines are used to carry out heavyand difficult tasks such as ploughing andharvesting.

• Plantbreeding,newagriculturaltechniques,fertilisers and insecticides contributegreatly in increasing theworld’sagriculturalproducts.

Medicine

• More diseases can now be cured withthe discoveries of new drugs, vaccines,antibiotics and the invention of bettersurgerytechniquesandequipment.

• Diseases can be diagnosed and detectedearlier with various tests and devices suchas the X-ray machines and ultrasoundscanningdevices.

Uses and benefits of science in daily life


Science offers various career opportunities according to one’s area of interest. Listed below are a few examples:(a) Doctor A person who has been trained in and

practises medicinal science.(b) Veterinarian An animal doctor.(c) Pharmacist A person who dispenses medicinal

drugs and advises on their uses.

Careers in science

Science is divided into a number of areas of study, namely(a) Biology The study of life.(b) Physics The study of matter, energy, force and

motion.(c) Chemistry The study of the composition and

chemical properties of substances.

1.1 Q1. What is the difference between ‘science’ and ‘technology’?

Q2. Give one benefit of science in the following areas.(a) Medicine (b) Transportation

Q3. State the field of science related to the following.(a) Discovering a cure for cancer.(b) Studying the behaviour of insects.(c) Forecasting natural disasters such as floods and tornadoes.(d) Discovering new comets.

Q4. List three careers that deal with human health.

(d) Engineer A skilled person who designs, builds

or maintains engines, buildings, bridges or roads.

(e) Architect A person who designs buildings and

advises on their construction.(f) Chemist A person trained in chemistry.

(d) Astronomy The study of planets and stars in the

universe.(e) Geology The study of rocks, minerals and the

structure of the Earth.(f) Meteorology The study of weather and climate.(g) Biochemistry The study of chemical processes in

living organisms.


Science Laboratory1.2The place where a scientist works is called a laboratory.Students carry out scientific investigations or experiments during science lessons in science laboratories.

We need to use apparatus to carry out experiments. The figure shows some common laboratory apparatus and their uses.

General laboratory apparatuses and their uses

100

5

10

15

20

5

10

15

20

5

10

15

20

0

1

2

3

4

5

6

7

8

9

10

Conicalflask Beaker Flat-bottomedflask

• Toholdbiggeramountsofliquidsorchemicals

Boilingtube

• Forheatingsmallamountsofliquids

Testtube

• Toholdsmallamountsofliquidsorchemicals

Measuring cylinder

• Tomeasurevolumesofliquids

Pipette

• Tomeasureafixedvolumeofliquids

Burette

• Tomeasuresmallvolumesofliquidsaccurately

Retort stand

• Toholdorsupportapparatus

Evaporating dish

• Toholdliquidsforevaporating

Crucible

• Toholdsolidsforstrongheating

Testtubeholder

• Toholdatesttubeduringheating

Spatula

• Totransfersmallamountsofsolids

Wire gauze

• Tosupportapparatusandensureevenheating

Tripod stand

• Tosupportapparatusduringheating

Bunsenburner

• Toprovideaflameforheating

Filterfunnel

• Usedtogetherwithafilterpapertofiltermixturesofsolidsandliquids


Symbol Danger of substances Examples Handling techniques

Explosive • Easily explodes

when mixed with other substances.

• Sodium, potassium

• Keep in paraffin.• Avoid contact with

water.

• Concentrated acids and alkalis

• Keep away from other substances including water.

Flammable or inflammable• Easily catches fire

and burns.

• Organic solvents such as ethanol, petrol and kerosene

• Keep away from fire or heat sources.

Toxic/poisonous• Causes death

or harm to the body if absorbed through the skin, swallowed or inhaled.

• Mercury, chloroform, lead, benzene, bromine, sodium cyanide, hydrogen sulphide

• Do not inhale, touch or taste the substances.

• Keep in a locked cupboard.

Corrosive• Causes damage to

the skin or eyes upon contact.

• Concentrated acids and alkalis, bromine, hydrogen peroxide

• Avoid contact with skin or eyes.

• Spill on body parts should be washed away quickly under running water.

Irritant/harmful• Irritates (causes

itchiness and rashes) skin, eyes and respiratory system.

• Ammonia solution, chloroform, dilute acids and alkalis

• Spill on body parts should be washed with a lot of water.

Radioactive• Gives out radiation

that can cause cancer or destroy bodily tissues.

• Uranium, plutonium, radium

• Keep in special lead containers.

Hazard warning symbols


Identifying the problem• First, we determine what we want to find out.• In order to do so, we need to observe things or happenings carefully to obtain information. Based

on our observation, we then ask questions about the things or happenings.

Forming a hypothesis• To make a smart guess to explain the problem.• The hypothesis has to be tested based on the evidence collected.

Planning an experiment

This section involves:• Identifying the variables involved. A variable is a condition that influences the results of the

experiment.• Determining the materials and apparatus required.• Determining the procedure to carry out the experiment, methods of collecting and analysing data.

Carrying out the experimentThis section involves:• Controlling the variables as planned so that the experiment is a fair test.• Collecting data through observations and measurements. All these must be done systematically,

accurately, objectively and honestly.

Analysing and interpreting data• Explaining the collected data in an objective and logical manner.• Giving an explanation about the pattern or relationship based on the data collected.

Making a conclusion

• State whether the hypothesis is true.• A conclusion should be made based on the data and not influenced by any unfair opinion.

Writing a report on the experiment• Present the aim, materials, apparatus and procedures, any table or graph and conclusion clearly in

the report.• It is important as a means of communication among scientists.


An example of a science report is given below.Ex

periment

Investigating the relationship between the length of a pendulum and the period of oscillation

Problem: How does the length of the pendulum affect the time of oscillation?Hypothesis: The longer the length of the pendulum, the longer the period of oscillation.Constant variable: Weight of the pendulumManipulated variable: Length of the pendulumResponding variable: Period of oscillationMaterials/apparatus: String, cork, wooden block, retort stand with clamp, stopwatch

and metre rule.Procedure: 1. A simple pendulum of 20 cm in length is

made as shown in the figure on the right. 2. The time taken for the pendulum to make

20 oscillations is recorded.

One full oscillation of a pendulum is the movement of the pendulum from P to Q and back to P again.

Reminder

3. The experiment is repeated using the pendulum at lengths of 40 cm, 60 cm, 80 cm and 100 cm.

4. Results are recorded in a table and a graph of the time taken to complete one oscillation against the length of the pendulum is plotted.

Results:

Graph of time taken to complete one oscillation against the length of the pendulum

Tim

e ta

ken

to c

ompl

ete

one

osci

llatio

n (s

)

Length of pendulum(cm)

Length of Time taken for Time taken for pendulum 20 oscillations one oscillation (cm) (s) (s) 20 16 0.8 40 25 1.3 60 31 1.6 80 36 1.8 100 40 2.0

Discussion:From the graph in the above figure, the time taken for one oscillation increases as the length of pendulum is increased.Conclusion:The longer the length of the pendulum, the longer the period of oscillation. The hypothesis is accepted.

A simple pendulum

Wooden block

StringRetort stand

Length of pendulum = 20 cm

P Q


Weight

The Earth pulls all objects to its centre. This pull is called the force of gravity or gravitational force.

The weight of an object is the pull of the Earth on the object. The weight of an object can change. It depends on the gravitational force that acts on the object at that place. Because of this, the weight of an object differs from place to place.

The weight of an object becomes less when the object is further away from the centre of the Earth. Thus, it is less on top of a high mountain than at sea level.

The weight of an object is measured using a spring balance or a compression balance. The SI unit for weight is Newton (N).

SPRINGBALANCE0

12

34

56

78

910

01002003004005006007008009001000

Scale

HookA spring balance A compression balance

J Disc

Scale

Weighing devices

Mass

The mass of an object is the quantity of matter contained in the object. Unlike weight, the mass of an object is constant everywhere. This is because the quantity of matter in an object is the same wherever the object is.

The mass of an object is measured using a lever balance, a beam balance or an electronic balance. The SI unit for mass is the kilogram (kg).

The Concept of Mass1.5


1.7 Q1. State two problems of having different standard units for a physical

quantity.

Q2. Other measurement units are still being used in certain parts of the world. These units can be converted to the SI units and vice versa. Solve the following problems.(a) You have bought 5 yards of cloth in another country. What is the

length of this cloth in metres? [Hint : 1 yard = 0.91 m](b) You need two kilograms of sugar. How much is it in pounds? [Hint : 1 pound = 0.45 kg]

Naturalphenomena Uses&benefits Careers

Stepsinscientificinvestigations

• Identifyingtheproblem• Formingahypothesis• Planninganexperiment• Carryingouttheexperiment

• Analysing/interpretingdata

• Makingaconclusion• Writingareport

Differences

What is science? Mass

Weight

Conceptofmass and

weight

Measuringtools

Length• Metrerule

Current• Ammeter

Time

• Stopwatch

Temperature• Thermometer

Mass• Leverbalance

Weight• Springbalance

Volume• Measuringcylinder

Physical quantity SI UnitLength Metre(m)Current Ampere(A)Time Second(s)

Temperature Kelvin(K)Mass Kilogram(kg)

Physical quantities & units

Introduction to Science

26 Science Mathayom 2

Fill in the blanks with the given words

time (t) spring balance forming a hypotesis same making conclusion technology physical mass (m) Newtons Ampere (A) metre (m) rules science gravity safety precautions metre (m) kelvin (k)

1. is the systematic study of nature and how it affects us and our environment.

2. is the application of scientific knowledge for the use of mankind.

3. Students must follow the and to avoid accidents in the laboratory.

4. The sequence of steps involved in a scientific investigation are identifying the problem; ; planning an experiment; carrying out the experiment; analysing

and interpreting data; ; and writing a report on the experiment.

5. A quantity is a quantity that can be measured. It is measured in SI unit.

6. The basic physical quantities are:

Physical quantity (symbol) SI unit (symbol)

(a) Length (l)

(b) kilogram (kg)

(c) second (s)

(d) Temperature (T)

(e) Electric current (l)

7. The differences between mass and weight:

Mass Weight

(a) The amount of matter contained in an object.

The force of acting on an object.

(b) Remains the at all places.

Changes according to places.

(c) Measured in kilograms. Measured in .

(d) Measured with a lever balance or a beam balance.

Measured with or a compression balance.

Chapter 1 Introduction to Science 27

Objective Questions

1. Which of the following statements is true of science?A Science helps us to solve all problems.B Science can only be studied in

laboratories.C Science is an understanding of natural

phenomena.D Science enables us to know the past

and the future.

2. Which of the following are natural phenomena?I Air pollutionII The ripening of a fruitIII The formation of cloudsIV The germination of a seedA III and IV onlyB I, II and III onlyC II, III and IV onlyD I, II, III and IV

3. The following describes X, a science-related profession.

X manipulates organisms to make products that benefit human beings. For example, producing new antibiotics or new biodegradable materials.

X is most probablyA a chemist C an astronomerB a pharmacist D a biotechnologist

4. P, Q, R and S are steps in lighting a Bunsen burner.

P – Light up the matchQ – Turn on the gasR – Open the air-holeS – Close the air-hole

The correct sequence to light the burner isA R → P → Q → SB R → Q → P → SC S → P → Q → RD S → Q → P → R

5. Which of the following pairs is not matched correctly?

Field Contribution of scienceA Agriculture Increase in food productionB Transportation More road accidentsC Medicine More successful surgeriesD Education Better teaching equipments

6. Figure 1 shows how a student heats up a beaker of water.

BeakerWater

Bunsen burnerTripod stand

Figure 1

After some time, the beaker cracks and the water leaks out. What mistake has he done?A The beaker is too small.B A taller tripod stand should be used.C The flame of the Bunsen burner is too

strong.D A wire gauze should be put below the

beaker.

7. Methanol has the following characteristics.

• Burns easily• Can cause death if swallowed.

Which hazard warning symbols are found on the labels of bottles containing methanol?I II

III IV

A I and II only C II and III onlyB I and III only D I, II and III only

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