WHAT IS SCIENCE
1. We see various natural phenomena in daily life. Natural
phenomena are things that happen in
nature. PMR 07
i. lightning, rainbow, melting of ice, growth of a baby into an adult and the
fall of ball to the ground are a few examples of natural phenomena.
ii. We want to know
why
and how all these things happen.
We search for answers. The study of science gives us the answers.
2. Science is the systematic study of nature and how
it affects us and our environment.
3. The information produced from the study of science is known as scientific
knowledge.
IMPORTANCE OF SCIENCE
1. Science plays important roles in our daily life. Here are some examples:
i. Science
helps
us
to understand
ourselves. Knowing how our body works, we can better take care of our health
and
safety.
ii. Science also helps
to understand
our environment.
This helps us to improve the quality of our
environment
and conserve it
for
our future generation
CAREERS IN SCIENCE
1. Science offers various career opportunities according to one’s area interest. For example doctor, engineer, veterinarian, pharmacist, architect, chemist and computer programmer.
2. Science is divided into a number of areas of study, namely
i. Biology - the study of life
§ ii. Physics - the study of matter, energy, force and
motion.
§ iii.Chemistry - the study of the composition and chemical
properties of substances.
§ iv.Astronomy - the study of planet and stars in the
Earth.
§ v. Geology - the study of rocks, minerals and the structure of the
universe.
§ vi. Meteorology - the study of
weather and climate.
§ vii.Biochemistry - the study of chemical process in
living
organisms.
SCIENCE LABORATORY
1.. Listed below
are
some
rules and safety
precautions in the
laboratory.
i. never enter the laboratory unless a teacher is present.
ii. do not eat, drink or taste any chemicals.
iii. always follow the teacher’s instructions.
2. Bunsen burner are used on the
containers
of hazardous
chemical substances to show their
characteristics. PMR 03
STEPS IN SCIENTIFIC INVESTIGATION
1. A scientific investigation is a series of steps done
systematically
to
study a problem or an event.
2. Each step involves the use of one or more science process skills.
PMR
03
3. The following shows the
sequence
of
steps involved in a scientific investigation.
4. Figure below shows some common laboratory apparatus and their
uses.
5. Some
substances in the
laboratory
are
hazardous or dangerous.
i. Hazard warning symbols are placed on
labels of bottles or containers of hazardous
substances to show the danger
of the substances.
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 solvent
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
or inhaled
|
* mercury
|
* do not inhale,
touch
or taste the
substances.
* keep in a looked cupboard.
|
|
Corrosive
* cause damage to the skin or eyes upon contact.
|
* concentrated acids and alkalis
|
* avoid contact with skin or
eyes.
* spill on body
parts should be washed away quickly under
running water.
|
|
irritant/harmful
|
* ammonia solution,
chloroform, dilute acids and alkalis.
|
* spill on body
parts should be washed with a lot of water.
|
|
Radioactive
* causes cancer or destroy
bodily tissues.
|
*uranium, plutonium,
radium.
|
* keep in special lead
containers.
|
6. The following shows the sequence of steps involved in a scientific investigation.
PMR
03
1. identifying the problem first, we determine what we want to
find out.
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 happening.
2. forming a hypothesis
To make a smart guess to explain the problem.
The
hypothesis needs to be
tested
based
on
the evidence collected.
this section
involves:
3. planning an experiment
identifying the variables involved. A variable is conditioning that influences the results of the experiment.
Determining the materials and apparatus required.
Determining the procedure to carry out the experiment, method of collecting and analysing data.
4. carrying out the experiment this
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.
5. analysing and interpreting data
explaining the collected data in an objective and logical
manner.
Giving an explaination about the pattern or relationship based on the data collected.
6. 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.
7. 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.
PHYSICAL QUANTITIES AND THEIR UNITS
1. There are five physical quantities which can be
measured, that is length, mass, time, temperature and electric
current.
2. Physical quantities can be measured in System International d’Units (SI) units. Its means International System of Units.
3. The following table shows the physical quantities and their SI unit.
Physical quantity
|
SI unit
|
Symbol
|
length
|
Metre
|
m
|
mass
|
kilogram
|
kg
|
time
|
Second
|
s
|
temperature
|
Kelvin
|
K
|
electric current
|
Ampere
|
A
|
Weight and Mass
1. The concept of weight and mass.
i. Weight is the gravitational force acting on an object.
ii. The greater the force pulling the object towards the centre of Earth, the
heavier of object.
iii. Spring balance is used to measure weight.
iv. Weight is measured in Newton (N)
1 N
|
=
|
0.1 kg
|
1 kg
|
=
|
10 N
|
v. Mass
is the amount of matter in an object.
vi. Mass
of an object can be measured by using beam
balance lever
balance or electronic balance.
vii. The SI unit for mass is kilogram
(kg). Mass can also be
measured in
gram(g) and milligram (mg).
I kg
|
=
|
1000 g
|
1 g
|
=
|
1000 mg
|
viii. The S.I. unit for length is the metre (m).
ix. The unit `metre’ is used to measure objects such as cloth, tables, poles and running tracks
x. Longer distances are measured in kilometres (km) and shorter distances are measured in centimetres (cm).
xi. The length of a curve is measured using a ruler and a thread, or opisometer
(measuring tool for maps).
xii. Temperature is
the degree of hotness or
coldness.
xiii. The S.I. unit for temperature is the Kelvin (k).
xiv. However,
in
daily usage, temperature is measured in the Celsius scale which is named after the Swedish scientist, Anders Celsius. The unit used for temperature
is degrees Celsius ( 0 C).
xv. The volume of regular shape or irregular shape solids can
be measured
using
water displacement method. The volume of water displaced is equal to the volume of the object. PMR 05
Standard form and prefixed form
1. The distance from the Earth to the Sun is 150 000 000000m
2. The mass of a hydrogen atom is
0.00000000000000000000000167g
3. For number like these, we can write them in the standard form of a x 10 n
Example:
150 000 000 000m = 1.5 x 10 11 m
0.00000000000000000000000167 g= 1.67 x 10 24 g
4. We can also write physical quantities in the prefixed form..
prefix
|
symbol
|
numerical value
|
value
|
tera
|
T
|
1 000 000 000 000
|
x 10 12
|
giga
|
G
|
1 000 000 000
|
x 10 9
|
mega
|
M
|
1 000 000
|
x 10 6
|
kilo
|
k
|
1 000
|
x 10 3
|
hector
|
h
|
100
|
x 10 2
|
deca
|
da
|
10
|
x 10 1
|
deci
|
d
|
0.1
|
x 10 1
|
centi
|
c
|
0.01
|
x 10 2
|
milli
|
m
|
0.001
|
x 10 3
|
micro
|
µ
|
0.000 001
|
x 10 6
|
nano
|
n
|
0.000 000 001
|
x 10 9
|
pico
|
p
|
0.000 000 000 001
|
x 10 12
|
femto
|
f
|
0.000 000 000 000 001
|
x 10 15
|
5. we can also change 45 000g into the kilo prefix.
45000g = 45 kg
1000
6. change 3 m into the mm prefix.
3 x 1 000 = 3
000mm
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