Revision Notes
Chapter 1: The Scientific Endeavour
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Science is the study of the things in this world.
A person who studies and practises science is called a scientist.
The application of scientific knowledge is called technology.
Science is divided into many branches e.g. Astronomy, Medicine, Botany, Meteorology,
Biology, Physics, Chemistry, Geology and Agriculture.
Famous scientists include Louis Pasteur, Gregor Johann Mendel, Charles Robert Darwin,
Albert Einstein, Marie Curie, James Dewey Watson.
Science has its limitations. It cannot solve all the problems in our society. E.g.
Scientists can accurately predict when a typhoon or an earthquake will occur, but it
cannot prevent them from happening.
Scientists know the cause of many diseases. However, they cannot always stop diseases
spreading from one person to another.
Scientists often work in a laboratory, but they can work anywhere.
Laboratory Safety Rules must be observed to prevent accidents in the labs.
Do’s
Read all instructions carefully and carry out
the experiments accordingly. When unsure,
always seek help from your teacher.
Don’ts
Do not enter the laboratory without your
teacher’s permission.
Keep the laboratory clean and tidy.
Do not eat or drink in the laboratory
Wear safety goggles to protect your eyes
when using chemicals or when heating.
Do not taste any chemicals.
Tell you teacher if you have an accident, spilt
anything or broken anything
Do not play or run in the laboratory
Wash your hands when you
completed an experiment
Do not put solids into the sink.
Do not pour any unused chemicals back into
their containers as this may cause
contamination.
9. Laboratory equipment and apparatus are used in the school laboratory. They are drawn as
sectional diagrams. The diagrams are in outline and must be in the correct proportions.
Test tube
Beaker
To contain or heat a small amount of solid in
liquid.
To contain, heat of mix chemicals
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Filter funnel
Conical flask
To separate an insoluble solid from a liquid
using filter paper
Round-bottomed flask
To mix liquid chemicals such as acids and
alkalis
Flat-bottomed flask
To prepare gases when heating is required
To prepare gases when heating is not
required
Water trough
Gas Jar
Measuring cylinder
To hold a large amount of water in a
container
Burette
To measure a certain volume of liquids
Thistle funnel
To accurately add a measured volume of
liquid
Pipette
To collect gases
To pour a liquid into a flask when preparing
a gas
To measure a fixed volume of liquid
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Tripod
Retort stand
To support a piece of apparatus when heating
Condenser
To hold a piece of apparatus
Thermometer
To change a vapour back into a liquid
Evaporating dish
To measure temperature
Crucible
To evaporate liquids and solutions
Wire gauze
To heat a solid strongly
Bunsen burner
To support a container (such as a beaker or
flask) during heating
To heat substances
10. Hazardous Warning symbols
Hazard Warning
Symbols
Types of Substances
______________substances
______________
substances
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Danger
Examples
poisonous if breathed,
swallowed or
absorbed through the
skin
alcohol, mercury
easily ignite and burn
petrol, alcohol
_______________
substances
_______________ or
irritating substances
destroy living tissue
upon contact,
including skin and
eyes
concentrated acids,
household oven
cleaner
involve a health risk
or irritate the skin
ammonia solution,
thinner, dilute acids
Causes radiation
Uranium, plutonium
239 and plutonium
241
____________ substances
React violently when
heated or struck
_________________
substances
Dynamite
11. The application of scientific knowledge is called technology.
• Different fields of technology
– Medical/Pharmaceuticals
– Industrial (Machinery)
– Information/Communications
– Measuring instruments
– New products/Chemicals/Materials
 The development of computers
– Improved the speed at which we do our work
– Improved the access to a wider source of knowledge
 The development of plastics
- Provided us with many light-weight and water-proof materials
 The development of mobile
- Made communication easier and faster
Benefits of technology
• The development of medicine
– Made more diseases curable
•
Abuses of technology
• Scientific knowledge have been used
to cause harm
Examples of technology that led to harm:
Atomic bombs (e.g. WWII);
Biological warfare (e.g. use of anthrax)
• Improper and even excessive use of
useful technology can also cause
harm
Pollution (e.g. disposal of non-biodegradable
plastics; excess fertilisers entering rivers;
The development of fertilisers and
genetically cloned plants
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burning of fossil fuels to supply electricity)
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Increased the production of food
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Improved the quality of food
Social problems (e.g. use of internet for
criminal activities, addiction to the use of the
internet and computer games)
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12.The Bunsen Burner- A Bunsen burner is used in the laboratory to heat things.
B_______________
_
C_____________
Air-hole
Gas jet
B___________
To light a Bunsen burner: ___________ the air hole.
 Light a match and hold it over the barrel.
 Turn on the gas tap with the other hand.
 ___________ the air hole

•
•
If air hole is opened, it will result in strike back.
Gas burns at the jet because of too much air
When ‘strike-back’ occurs, turn off gas supply quickly to prevent the barrel from
becoming too hot.
With the air hole closed
(L___________________flame)
Visible with a whitish-yellow zone
caused by the incomplete burning of the
gas
Smoky because particles of carbon are
formed during the incomplete burning
With the air hole opened
(Non-___________________flame)
_________________ and is difficult to see
(____________ and ________ flame)
U____________ and not very hot
Clean as there is sufficient air entering the
barrel to allow all to the gas to burn
completely
(Non- ____________ flame)
S___________ , strong and very hot
(Not suitable for __________________)
(Suitable for _______________)
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What are variables in an experiment?
Independent Variable - The independent variable is the one that is intentionally changed by
the scientist.
The dependent variable is the one that changes as a result of the changes made in the
independent variable.
The constants in an experiment are all the factors that remain unchanged.
Independent variable: ________________________________
Dependent variable: ____________________
Control variables: __________________________
Independent variable: ________________________________
Dependent variable: ____________________
Control variables: __________________________
Independent variable:
________________________________
Dependent variable: ____________________
Control variables: __________________________
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