Chapter 1

Introduction TO Science

What is Science?

1. The definition of science is "knowledge attained through study or practice,"

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

3. It is the study of natural phenomena.4. Science helps us find out about ourselves,

plants and animals, our environment and things around us.

5. Scientific knowledge is always growing. What we learn in science today is a result of many years of study.

6. Science helps us understand natural phenomena. Every natural phenomenon makes us wonder why it happens. Discovering the answers leads us to new scientific knowledge.

• Science is a continuing effort to discover and increase human

knowledge and understanding through disciplined research.

Using controlled methods, scientists collect observable

evidence of natural or social phenomena, record measurable

data relating to the observations, and analyze this

information to construct theoretical explanations of how

things work. The methods of scientific research include the

generation of hypotheses about how phenomena work, and

experimentation that tests these hypotheses under

controlled conditions

Natural Phenomena

• Natural phenomena are fascinating.• Examples of a natural phenomenon are

– a baby growing up and becoming an adult,– ice can melt.– The growth of a plant– Formation of a rainbow– Formation of thunder– Rain formation

• We want to know why these things happen. We search for answers.

• The study of science gives us these answers. Science covers everything in the universe.

Importance of Science in Everyday Life

1. Every aspect of our life is related to science. E.g. our food and

clothes are produced using scientific knowledge.

2. Scientific discoveries make our lives more comfortable. With

scientific knowledge we can produce machines and appliances

such as light bulbs, cars and computers.

3. Science helps us to understand our environment. We can use this

knowledge wisely. For example, we can recycle paper to conserve

our resources. It protects our environment by reducing the

number of trees that need to be cut down to make paper.

4. We can create scientific knowledge and also use it. We can manufacture

plastic and synthetic materials. These are used to make many different

objects such as pipes, umbrellas, toys and furniture.

5. We have invented instruments such as spectacles, the microscope and

the telescope. These help us to see better. The stethoscope enables us

to hear better.

6. The application of scientific knowledge is called technology. Technology

helps us to introduction to Science progress in every aspect of our lives.

Transport

• Transport is easier, faster, more comfortable and safer today than it used to be.

Communication

1. The telephone, facsimile, radio, television and computer help us to communicate with one another. The launching of communication satellites makes long distance communication possible.

2. Information Communication Technology (ICT) is very important in developing the industrial, medical, trade and administrative sectors of a nation.

Agriculture

1. Technology helps us to produce more food.2. Machines have been invented to do most of the

heavy and difficult work. Ploughing, scattering of seeds, harvesting and crushing can now be done by machines easily and quickly.

3. By using modern fertilizers and insecticides, we can increase agricultural production.

Construction1. In the past, houses and buildings were made from materials

found close by. This means only small and simple buildings could be built.

2. As we progress, we require bigger buildings and more complex structures. We need, for example, office blocks, apartments, stadiums and airports.

3. Strong bridges need to be built over rivers. To prevent flooding, we need to build dams. Dams also generate electricity. More importantly, they supply water to millions of people in the cities. Today, we have developed stronger building materials for building dams. Steel, concrete and reinforced glass are some examples of strong materials used in construction today.

Medicine1. A century ago, people rarely lived beyond 30 or 40 years.

Today, we can live beyond 70 years because of the progress in the medical field.

2. The invention of X-ray machines, lasers, electrocardiogram (ECG) and dialysis machines have helped to save the lives of many patients. Medical operations have become easier and safer.

3. The discovery of new medicines, vaccines and antibiotics have also helped to save lives. They reduce the pain and suffering of patients. They help to cure and prevent many diseases and illnesses.

Careers in Science

• Doctor - someone trained in medical science.• Engineer - a person who designs, builds and

maintains engines, buildings or roads.• Nurse - a specialist in caring of patients.• Veterinarian - an animal doctor.• Architect - a person who designs buildings.

• Pharmacist - someone trained in the field of medicine and drugs.

• Chemist - someone trained in chemistry.• Computer programmer - a developer of

computer software programmes.

Study of Science• Astronomy - the study of planets and stars.• Biology - the study of life.• Physics - the study of matter and energy.• Biology - the study of processes and functions of

systems in the human body.• Geology - the study of rocks and minerals.• Meteorology - the study of weather and climate.• Chemistry - the study of the composition and

chemical properties of substances.• Biotechnology - the study of the industrial use of

living organisms.• Biochemistry - the study of chemical substances and

chemical processes of living things.

1.2 A science Laboratory

1. Scientists can work anywhere. A scientist studying tropical plants and animals for example, could make the Malaysian jungle his laboratory. However, most scientists do their experiments in a laboratory.

2. However, some chemicals are dangerous. We need to handle these chemicals carefully. We need to know about safety in the laboratory.

Discipline in the science laboratory

1. No pupil is allowed to enter the laboratory without the teacher's permission.

2. If the class arrives before the teacher, line up outside the laboratory and wait quietly.

3. After entering the laboratory, go to your places in an orderly manner.

4. No food or drink should be taken into the laboratory.

5. Nothing is to be taken from the laboratory.6. When in doubt ask your teacher for help and

advice.

Safety rules in the science laboratory

1. Pupils must not carry out experiments without the teacher's permission.

2. Read and understand the instructions given before you attempt to do the experiment. When in doubt always ask your teacher.

3. Handle all apparatus correctly and carefully.4. Do not light a Bunsen burner with a piece of paper.

Turn off the gas after use.5. Do not play or walk around unnecessarily in the

laboratory.

6. Always read the label on the bottle before using the chemical it contains.

7. Do not handle chemicals with your fingers. Always use a spatula.

8. Do not waste any chemical. Use only the required amount.

9. Do not pour any excess chemical back into the reagent bottle.

10. When heating any solution in a boiling tube, always make sure that the mouth of the tube is not pointed towards anybody.

11.Water, gas and electricity must not be wasted.12.Solid wastes must be put in the bins provided. Do

not throw solid wastes into the sinks.13.Do not taste any chemical or inhale any gas.14.Breakages and faulty equipments must be reported

to the teacher at once.15.Any mishaps, cuts, burns, scalds or substances

which get into your mouth must be reported to the teacher at once.

16. Do not damage any fitting or the electrical mains in the laboratory.

17. When the practical periods are over, wash all used apparatus and return them to their respective places.

18. Wash your hands thoroughly.19. The benches must be left clean and tidy.20. All taps and switches must be turned off.

Some simple rules and precautions

• Do not heat a gas jar directly with a Bunsen flame.• Correct way of inhaling gas.• Read the label on the bottle before using the

chemical inside.• Never point the mouth of the boiling tube towards

anybody when heating.• Do not stand too close to the flame when heating up

a solution.• Tie your hair neatly when doing experiments.

Accidents and First Aid• Inflammable liquid: If an inflammable liquid is spilt,

put out all flames immediately.• Minor cuts and abrasions: Apply tincture of iodine

on a pad of cotton wool. Cover with sterilized dressing.

• Deep cuts: Apply a thick pad of gauze or cotton wool over the wound. Send the person to a doctor or a nearby clinic.

• Scalds: Bathe the affected part with a warm saturated solution of sodium carbonate.

• Burns: It is best for the teacher to send the person to a doctor or a clinic.

6. Poisoning: Should a chemical or a liquid get into your mouth, spit it out into the sink. Rinse your mouth with plenty of water. Consult a doctor at once.

7. Acid: If you have swallowed an acid, rinse your mouth with plenty of water. Then milk of magnesia (or dilute lime-water) should be taken. Consult a doctor at once.

8. Alkali: If you have swallowed an alkali, rinse your mouth with plenty of water. Then lemon juice (or 1% acetic acid) should be taken. Consult a doctor immediately.

9. Eye injuries: If due to an acid or an alkali, wash with plenty of water. Any injury to the eyes must be attended to by a doctor immediately.

10. Electric shock: The electric current must be switched off immediately. With the help of an insulator, get the victim away from the source of electric current. In serious cases artificial respiration may be required

Hazordous Symbols1. (Mixture of hydrogen and

air, nitrates, sodium, potassium)– Keep away from fire or heat

sources.

2. (Petrol, kerosene, ethanol, white phosphorus, yellow phosphorus)– Keep away from fire or heat

sources.

8-10-091. Mercury, lead, chlorine,

sodium cyanide, hydrogen sulphide.– Keep in a locked cupboard.

2. Concentrated acids and alkalis, bromine, hydrogen peroxide.– Be careful not to spill onto

your clothes or yourself. If accidentally spilt, wash quickly with lots of water.

1. Ammonia, dilute acids, chloroform, alcohol, bromine– Be careful not to spill onto

your clothes or yourself. If accidentally spilt, wash quickly with lots of water.

2. Uranium, plutonium, radium, radioactive carbon

– Keep in special lead containers.

Common Laboratory Apparatus

Common Laboratory Apparatus

Way to Use Bunsen Burner

1. Close the air hole completely by turning the collar.

2. Hold a lighted match or wooden splinter near the mouth of the barrel.

3. Turn on the gas slowly.4. When the flame is seen, slowly open the air

hole by turning the collar.

Bunsen Burner

FLAME

Luminous flame vs Non-luminous flame

a. Yellowb. Easy to seec. Produces a lot of soot.d. Shape changese. Not very hotf. Incomplete burning

g. Not suitable for heating

a. Blueb. Not easy to seec. Does not produce soot

d. Constant shapee. Very hotf. Complete burningg. Suitable for heating

Bunsen Burner

1. The Bunsen burner gives different flames under different conditions. When the air hole is closed, a yellow flame is produced. This is called a luminous flame. This flame is easy to see. It produces a lot of soot.

2. When the air-hole is opened, a blue flame is produced. It is called a non-luminous flame.

1.3 The Steps in a scientific Investigation

1. Identify problem2. Form a hypothesis

3. Plan investigation (experiment)4. Control variables

5. Collect data6. Analyse data

7. Interpret data8. Make conclusions

9. Results support hypothesis or Results do not support hypothesis

10.Prepare report

Activity: The Pendulum experiment

• The steps in the scientific method for the experiment on the swing of a pendulum.

1. The problem and hypothesis are determined at the beginning.

2. (a) The manipulated variable is the pendulum length.– (b) The responding variable is the period of swing.– (c) The fixed variable constant is the pendulum weight.3. The time recorded is based on actual observations. It was

not guess work.4. The conclusion is drawn based on the analysis of the data

obtained.

1.4 Physical Quantities and Their Units

1. A physical quantity is a quantity that can be measured. Examples of physical quantities are length, time, mass, temperature and electric current.

2. Physical quantities are measured in S.I. units. The S.I. symbol is an abbreviation for the French term Systeme International d'Unites. It means International System of Units.

Basic Quantities

Physical quantity S.I. unit Symbol Instrument

Length Metre m Metre rule

Mass Kilogram kgLever or beam

balance

Time Second sStop clock or stop

watch

Temperature Kelvin K Thermometer

Electric Current Ampere A Ammeter

Prefixes Used in Measurement

1. Prefixes are useful in expressing physical quantities that are either very big or very small.

2. The value of any physical quantity can be changed to prefix form. See the examples below.

– Write 840 000 g with the kilo prefix.– 840 000 / 1000 = 840 kg

Symbol and Prefixes

Symbol and Prefixes

Prefix Symbol Value of Prefix

kilo- k 1000centi- c 1/100milli- m 1/1000

Physical quantities and prefixes

Value of physical quantity Prefix form

0.005 m 5 mm0.25 m 25 cm8000 m 8 km250 g 0.25 kg

Exercise

1.Complete the table….

2. State the symbol and value for the tollowir, prefixes.

– Centi:_______– Kilo: ________– Milli: ________

Is Mass the Same as Weight?

Concept of Weight

• Weight of an object:– The pull of the Earth on that object.– The pull of the Earth is call force of gravity.– The value always not the same– Changes from place to place (depend on how

strong the pull of Earth in that place)• S.I. unit: newton (N)• Measuring device: Spring balance

The Concept of Mass• Mass of an object:

– Amount of matter in the object.– Value does not change (same everywhere).• S.I. Unit : kilogram (kg)• Smaller masses measured in grams (g) or miligrams

(mg)• Measuring device: • lever balance• triple beam balance,• electric balance

Weight MassDue to pull of Earth

on the object The amount of

matter in the objectValue not always the

sameValue always the

sameSpring balance Triple beam balance,

lever balance, electronic balance

Newtons (N) Kilograms (kg)

1.6 Learning How to Use Measuring Tools

Measuring length

• S.I. unit for length is metre (m).• Short lengths – centimeters (cm)

or milimeters (mm)• Long distances – kilometres (km)

1 cm = 10 mm1 m = 100 cm

1 km = 1000 m

Tools for measuring length

• To measure the length of short straight lines, we use:– Metre rule– Half-metre rule– ruler

• Measuring the length of an object–If the position of the eye is at A or C,

the reading taken is not accurate. This error is known as parallax error.

• Measuring the length of a straight line- The lengths are measured by taking

several readings. The average length is then determined.

• The measuring tape - To measure the length of long straight

lines.

• Measuring the length of a curve– Some thread and a ruler are used for

measuring the length of a curve.– The thread is placed along the length of the

curve PQ. The end of the curve is marked on the thread. (refer to text book)

– The length of the thread is later measured using the metre rule.

– The length of the curve is measured three times. Then the average length is determined.

External and Internal Calipers

• Calipers - To measure diameters of round or cylindrical objects.

• External calipers – to measure the external diameter of an object.

• Internal calipers – to measure the internal diameter of an object

Measuring the external diameter of a beaker

Measuring the external diameter of a beaker

Measurement of Area1. The S.I. unit for area is square metres

(m2).2. The area of objects with regular shapes

such as rectangles, triangles and circles are calculated using mathematical formulae.

3. The area of regular or irregular shaped objects can be estimated by using graph.

Measuring area using graph

• The numbers of squares by the shape is then counted using the following method:– Count the number of complete squares.– An incomplete square is counted if half or

more of the square is covered.– Do not count as incomplete square if less

than half of the square is covered

Measurement of Volume1. The S.I. unit for volume is cubic metres,

(m3).2. All these units can be used to measure

the volume of liquids. However, the volume of liquids is usually measured in metric unit i.e. litre (l) and millilitres (ml).

3. The volume of solids is measured in cm3 and m3 units.

Volume of liquids• The measuring cylinder must be placed on a flat

surface.• The level of the liquid in a measuring cylinder is

curved downwards. This curve is called the meniscus.

• Your eye, must be at the same level as the bottom of the meniscus when reading the volume.

• This must be done for all liquids except for mercury where the meniscus curves upwards. The correct eye position prevents parallax errors.

Measuring liquids

• Measuring cylinder• Using a pipette• Using a burette

Water Displacement Method• To measure volume of a regular object and

irregular object.• How it works?

– The object is dropped into a measuring cylinder filled with water.

– Water level will rise because it has been displaced by the object.

– The increase in the volume of the water in the measuring cylinder is equal to volume of object.

Volume of SolidsWater Displacement

Measuring the volume of irregular solids with a eureka tin

Choosing Suitable Measuring Instruments

1. Measuring instruments measure definite quantities.

2. All measurements made are only close estimates of the values of the quantities. They cannot be 100% accurate.

3. We need to consider how precise and accurate a measurement is.

Accuracy1. The accuracy of a measurement is how close

the measured value is to the real value.2. The difference between the measured value

and the real value is the error in the reading. If the error between the measured value and the real value is small, the measurement is precise.

3. The accuracy of a measurement can be improved by taking several readings. The average reading is more accurate than a single reading.

Precision 1. Precision is the difference in values between

several measurements obtained in the same way.

2. Precision in measurement can be improved if a more precise measuring instrument is used.

3. A micrometer screw gauge or a vernier calipers is more accurate compared to a ruler because the divisions on its scale are smaller.

1.7 Importance of Standard Units in Everyday Life

• We cannot able to carry out our daily activities without measurement systems.

• In the past, various of systems of measurement were used– Length: Foot, yard, chain, mile– Weight: pound, ounce, kati and tahil

• The use of standard units makes it easier for people from different countries to communicate with each other.

• The use of standard unit means a measurement in that unit has the same value anywhere in the world.