『Science Form 1』

Chapter 1:Introduction to Science

-What is Science?
Science is the study of natural phenomena.
Examples:
(a) Science studies what happens in our surroundings and why they happen.
(b) Science studies the growth of a human being from the time it is formed in the mother's womb until it is an adult。
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-Natural Phenomena
Natural phenomena are incidents that take place on their own in our natural surroundings.
Natural phonomena take place all the time, involving living things and non-living things.
Examples of natural phenomena include:
(a) earthquakes
(b) Volcanic eruptions
(c) monsoons
(d) eclipses of the moon and the sun
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-Uses and Benefits of Science
1. Science helps us to solve problems
Science has helped us to supply water to our paddy fields by irrigation. We are able to control floods. We are able to controlplant pests and so produce more food.
2. Science helps us to make things quickly
With the help of machines invented by scientists. We are able to make things very quickly in large quantities.
3. Science helps us to make our work easier
Machines make our work easier. A tractor can harvest paddy in a short time. This saves us a lot of time and work.
4. Science helps us to enjoy our leisure
The television and the computer games have made our leisure more enjoyable. The motorcar enables us to take our famlily members for joy rides whenever we are free.
5. Science make communication easy
Information can now be relayed through telephones, computers, discs and satelites.
6. Science helps us to maintain good health
With the discovery of more drugs, we are now able to live healthily. Advance in surgery has even made the transfer to organs from person to person possible. We can expect to live much longer than our forefathers.

STEP IN SCIENTIFIC INVESTIGATION
1) Identifying the problem
2) Suggestion a hypothesis
3) Identifying the variables
4) Carrying out an experiment
5) Collecting data/observations
6) Analysing and interpretation data
7) Form a conclusion

Physical Quantity	SI Unit	Symbol
Length	metre	m
Mass	kilogram	kg
Time	second	s
Temperature	kelvin	K
Electrical current	ampere	A

Physical quantties can their units

-There are five physical quantities which need measurement. They are:
(a) length
(b) mass
(c) time
(d) temperature
(e) electrical current

Prefix	Symbol	Value
giga	G	1 000 000 000
mega	M	1 000 000
kilo	k	1 000
hecto	h	100
deca	da	10
desi	d	0.1
centi	c	0.01
milli	m	0.001
micro	u	0.000 001
nano	n	0.000 000 001
pico	p	0.000 000 000 001

-These are the prefixes and Symbols for units
SI units have prefixes and symbols

Weight
-The weight of an object is the pull of the force of gravity of the Earth on it.
-The S.I. unit for measuring weight is the newton (N).
-The weight of an object can be measured by means of a newton spring balance or a compression spring balance.
-The moon's gravitational pull is only one-sixth(1/6) of the Earth's.
- An astronaut weighing 600N on the Earth will weigh only 100N on the moon.

Mass
-The mass of an object is the quantity of matter(substances) in the object.
-The mass of an object cannot change because it always contains the same amount of substances.
- mass is measured by using:
(a) a lever balance
(b) a triple beam balance
(c) a Butcher lever balance
-The S.I. unit for mass is the kliogram (kg). But it is also measured in gram (g) and milligram (g).

different between mass and weight

1)weight and mass are two different quantities, although in daily life, we sometime use the two interchangeably.
2)the different between weight and mass are as follow:

.weight mass
________ _________
>Force of gravity that acts on the object >Quantity of matter in the object
>Weight of an object changes from place to place > mass of an object is constant
>Netwon(N) >Kilograms(kg)
>Spring balance, compression balance >Beam balance, lever balance


Exercise
1) what is weight?
2)what is the S.I unit for weught?
3)name two types of balances that can be used to measure weight and m***???
4)which is not an S.I unit?
A kilogram
B Kelvin
C kilometer
D ampere

5)which of the following show the correct conversion?
A 2 900 meter= 29 kilometeres
B 53 800 grams= 53.8 kilograms
C 15 kilometres= 1500 centimetres
D 3600 seconds= 360 hours

Mass	Different	Weight
Quantity of matter contained in an object	Definiton	The Earth's gravitational pull on an object
Kilogram (kg)	S.I. Unit	Newton (N)
Lever balance Triple beam balance Butchart balance Electroic balance	measuring tools	Newtom spring balance compression spring balance
Mass of an object does not change	Characteristic property	Weight of an object changes from place to place

Differences Between Mass and Weight