Science – Scientific Enquiry

1. Science
- Science, study, natural things, everywhere.
- Various branches, chemistry (chemicals), physics (nature, matter), biology (living things), life science (Study, genes).
2. Scientific Method
- Way, scientists, find out, things
- Make observations, five senses
- Systematic thinking, make inferences, experimental evidence
- Record information, analyse results
- Draw conclusion
- Keep mind, open, curious, eager to learn
3. Lab safety rules
- Wear goggles, heating
- Point test-tube away
- Dispose leftover chemicals
- Don’t eat/drink in lab
- Report breakage/spillage/accident
- Read instruction carefully, ask if in doubt
4. Symbols
- Skull: Toxic substance
- Flame: Flammable substance
- Test tube, hand and a block: Corrosive substance
- Circular stuff: Radioactive substance


5. Uses of apparatus
a) Retort stand – to support the apparatus during experiment
b) Tripod stand – to support the apparatus while heating
c) Filter funnel – to separate a solid from a liquid with the help of a piece of filter paper
d) Beaker, Conical flask – to contain chemicals and for carrying out reactions during an experiment
e) Test tube – to contain a small amount of a substance during an experiment
f) Measuring cylinder – to measure the volume of liquids
g) Gas jar – to collect gases
h) Water trough – to contain water during an experiment; especially when preparing gases
i) Test tube holder – to hold the test tube during heating
j) Evaporating dish – to evaporate liquids

6. The Bunsen burner
- Named after Robert Wilhelm Bunsen, a German scientist
- Parts of a Bunsen burner
a) Barrel – to raise the burner to a suitable height for burning to take place
b) Collar – to control the amount of air entering the barrel
c) Air hole – to allow air to enter the barrel
d) Jet – to allow gas to rush out to the barrel
e) Base – to support the burner
f) Gas tap – to control the amount of gas entering the barrel

- Differences between luminous and non-luminous flame
- First will be luminous, next will be non-luminous
a) Orange colour, not very hot / Blue colour, very hot
b) Produces soot / Does not produce soot
c) Unsteady / Steady
d) Not suitable for heating / Suitable for heating

7. Srikeback
- Too little gas, too much air
- Gas burns at jet instead of top of barrel
- Burner becomes dangerous, hot

Section A: Multiple Choice Questions
1. The ____________ of the Bunsen burner controls the amount of air entering it.
A. Base
B. Collar
C. Air-hole
D. Jet ( )

2. Which of the apparatus is used to seperate solids from liquids using a filter paper?
A. Filter funnel
B. Tripod stand
C. Conical flask
D. Evaporating dish ( )

3. Safety goggles prevent injury to one’s __________.
A. Mouth
B. Eyes
C. Ears
D. Hands ( )

4. The contents in the bottle are labelled ___________.
A. Flammable
B. Corrosive
C. Radioactive
D. Toxic ( )

5. In a “strike-back”, the Bunsen burner becomes very hot because ______________.
A. The air-holes are fully open.
B. The flame is the hottest.
C. All the gas is burnt completely.
D. The flame isd burning at the jet. ( )

6. Which of the following best describes a non-luminous flame?
A. Strong, steady and produces no soot
B. Sooty and steady
C. Orange in colour
D. Obtained when air-holes are closed ( )

7. The following are steps in lighting a Bunsen burner.
What are the correct sequences to lighting up a Bunsen burner?
I. Turn on the gas
II. Close the air holes
III. Light a match
IV. Place the lighted match above the barrel
A. I, II, III and IV
B. II, I, III and IV
C. II, III ,IV and I
D. I,III,II and IV ( )

8. Which of our senses do we use when observing the burning of a substance?
A. Sight, smell, taste
B. Touch, smell, hearing
C. Sight, smell, hearing
D. Sight, taste, touch ( )

9. When the air-holes are open, the flame is _________.
A. Luminous
B. Pale blue in colour
C. Unsteady
D. Sooty ( )

10. A “strike-back” occurs when there is _______________.
A. Too much air
B. Too little air
C. Too much gas
D. Too much soot ( )

11. To heat a substance strongly, we use a __________________.
A. Luminous flame
B. Non-luminous flame
C. Yellow flame
D. Sooty flame ( )

12. Which of the following is not part of the scientific method?
A. Observing
B. Plagiarising research notes
C. Inferring
D. Studying other scientist’s past research ( )

13. _________ is the branch of science regarding matter and energy.
A. Biology
B. Astronomy
C. Chemistry
D. Physics ( )

14. The yellow flame of the Bunsen burner is due to the glowing of ________.
A. The gas
B. Unburnt carbon
C. Copper
D. Sodium ( )

15. The apparatus used for measuring 41.3 cubed centimeters of liquid accurately is _____.
A. The burette
B. The pipette
C. The beaker
D. The round-bottom flask ( )

Section B: Structured Questions

1. Fill in the blanks.

The _____________________ method is the way scientists found out around them.
In their research, they study the ______________________ of work already done so as to build upon it. Using ________________ thinking, they proceed to make inferences based on the experimental evidence. Next they keep an accurate _______________ of their findings by refer to and build upon their findings. Nevertheless, they keep a ______________________ mind to any dispute as they are eager to learn.

2. List the steps involved in lighting a Bunsen burner.
I. ______________________________________________________
II. ______________________________________________________
III. ______________________________________________________
IV. ______________________________________________________

3. What is a “strike-back”? _______________________________________________________

4. State the function of the following parts:
(i) Air hole - ____________________________________________________
(ii) Base - ____________________________________________________
(iii) Collar - ____________________________________________________

Section C : Free- response Question
1. What type of flame should be used to boil a test- tube of water? State two reasons.





2. What two precautions should we take to protect ourselves and others while heating a test tube of water?