science form 1

1. CHAPTER 7:
Air

2. KEYWORD (page 195)
• Oxygen
• Carbon dioxide
• Nitrogen
•Inert gases
• Helium
•Neon
•Argon
•Krypton
•Xenon
• Carbon cycle
• Oxygen cycle
•Global warming
•Greenhouse effect
• Combustion
• Fire extinguisher
• Air pollution

3. Where is the air??

4. We can
feel the
air

5. atmosphere
• Layer of air = atmosphere
• Consist of many gases (eg:
nitrogen, oxygen, carbon
dioxide, inert gas)
• Also contain dust,
water vapour, microorganism
AIR

6. atmosphere
• Layer of air = atmosphere
• Consist of many gases (eg:
nitrogen, oxygen, carbon
dioxide, inert gas)
• Also contain dust,
water vapour, microorganism
AIR
• Helium
• Argon
• Neon
• Xenon
• krypton

7. 7.1 COMPOSITION OF AIR
Air is a mixture of nitrogen, oxygen, carbon dioxide and inert gas
THE COMPOSITION OF
AIR
AVERAGE PERCENTAGE
OF ITS COMPONENTS BY
VOLUME
Nitrogen 78 %
Oxygen 21 %
Carbon Dioxide 0.03 %
Inert gases and others 0.97 %

8. Nitrogen is
an inactive
gas
Carbon dioxide
important for
photosynthesis
Air also contains
water vapour,
microorganism
and dust

9. Nitrogen is
an inactive
gas
Carbon dioxide
important for
photosynthesis
Air also contains
water vapour,
microorganism
and dust

10. EXPERIMENT: TO DETERMINE THE PERCENTAGE OF OXYGEN IN THE AIR
5
4
3
2
1
Water level increase to the level marked 1.
It shows that composition of oxygen is 1/5 or 21% of the
air.

11. Nitrogen is
an inactive
gas
Carbon dioxide
important for
photosynthesis
Air also contains
water vapour,
microorganism
and dust

12. Prove that
air contains
WATER
VAPOUR

13. Prove that
air contains
DUST

14. Prove that air
contains
MICROORGANISM
A B
B

15. IS AIR A MIXTURE???
YES!!
The components can be separated
by a physical method
(FRACTIONAL DISTILLATION)

16. Without air

17. THE
IMPORTANCE
OF GAS
Oxygen
Carbon dioxide
nitrogen Inert gas

18. oxygen
Carbon dioxide
Water
vapour
- respiration

19. oxygen
• Combustion of rocket engine
• Welding and steel cutting • Preparation
of various
compound

20. Carbon dioxide
• Production of
carbonated
drink
• Fire
extinguisher
• Photosynthesis

21. Nitrogen
Nitrogen cycle
Nitric acid and
ammonia
Cooling agent

22. Inert gas
Helium in hot air
balloon
Argon gas in
light bulb
Neon gas in advertising
light

23. CARBON
CYCLE
ABSORB CARBON DIOXIDE
- Photosynthesis
RELEASE CARBON DIOXIDE
- Respiration
- Decomposition
- Combustion

24. CARBON
CYCLE
ABSORB CARBON DIOXIDE
- Photosynthesis
RELEASE CARBON DIOXIDE
- Respiration
- Decomposition
- Combustion
Maintains the content of CO2

25. OXYGEN
CYCLE
NEED OXYGEN
- Respiration
- Combustion
- Rusting
- Decomposition
RELEASE OXYGEN
- Photosynthesis
Very important !!!!!

26. OXYGEN
CYCLE
NEED OXYGEN
- Respiration
- Combustion
- Rusting
- Decomposition
RELEASE OXYGEN
- Photosynthesis
Please appreciate!!!!!

27. WAYS TO
PREVENT
INTERFERENCES
IN THE OXYGEN
AND CARBON
CYCLES

28. Air pollution = carbon dioxide INCREASE

29. Deforestation= oxygen DECREASE

30. CAUSE INTERFERENCES IN
OXYGEN AND CARBON CYCLES

31. CONSEQUENCES OF
THIS INTERFERENCE:
1.Global Warming
2.Greenhouse Effect

32. GLOBAL WARMING

33. GREENHOUSE EFFECT

34. WAYS TO PREVENT
INTERFERENCES IN
THE OXYGEN AND
CARBON CYCLES

35. 1. Prohibit illegal logging

36. 2. Avoid using excessive pesticides

37. 3. reforestation

38. excessive release of smoke from vehicles

39. 5. Do not burn forests

40. 7.2 COMBUSTION

41. conditions needed for combustion
by removing one
of the conditions
needed, we can
prevent
combustion

42. Prove that fuel is needed for
combustion
Glass rod and
stone will not
burn while
wood and
candle will
burn
+

43. Prove that air (oxygen) is needed
for combustion
If we put a glass
plate over the
chimney, the
flame finally goes
off because the air
is not available.

44. Prove that heat is needed for
combustion
in the presence
of water, the
ignition
temperature of
paper is not
reached

45. Why do we
use water to
extinguish
fire?

46. Why do we
use water to
extinguish
fire?
water is exceptionally good at absorbing heat
BECAUSE

47. FIRE EXTINGUISHER
Protective tool
that is used to put
out a fire or
handle a small fire

48. Various substance used
in the fire extinguisher

49. Material on fire:
SOLID
(wood, cloth, paper)

50. Material on fire:
LIQUID
(oil, varnish, paint)

51. Material on fire:
GAS
(propane, acetylene, methane)

52. Material on fire:
METAL
(potassium, sodium, calcium)

53. Technique to remove the conditions needed for combustion:
1. COVERING
(cut off the contact of fuel with air/oxygen)

54. Technique to remove the conditions needed for combustion:
2. COOLING
(cooling the surface of burning materials)

55. Technique to remove the conditions needed for combustion:
3. REDUCING AMOUNT OF BURNING MATERIAL
(separate/keep away the burning materials)

56. Safety
measures to
prevent the
occurrence
of fire

57. 7.3 AIR POLLUTION
Unwanted substances in the air that
are harmful to living things and
environment
Common air pollutants are dust,
carbon monoxide, lead,
chlorofluorocarbon (CFC), pesticides

59. CAUSES AND EFFECTS OF AIR POLLUTION
1. Health problem –asthma, lung cancer, headache, death

60. 2. Building and infrastructures – Acid rain corrodes
concrete/limestone buildings, speeds up iron rusting
CAUSES AND EFFECTS OF AIR POLLUTION

61. CAUSES AND EFFECTS OF AIR POLLUTION
3. Plants and animals –Depletion/damage of food resources
(water acidic, smoke decrease sunlight reaching to earth)

62. CAUSES AND EFFECTS OF AIR POLLUTION
4. Climate–haze, greenhouse effect, thinning of ozone layer
and acid rain

63. WAYS TO PREVENT AND CONTROL AIR POLLUTION
1. Law enforcement–fine smokers, fine person who conduct
open burning, prohibit factories (away from housing area)

64. WAYS TO PREVENT AND CONTROL AIR POLLUTION
2. Education – educate effect/way to prevent air pollution,
organize campaign, encourage usage of public transport

65. WAYS TO PREVENT AND CONTROL AIR POLLUTION
3. Sciece and technology – implement hybrid technology,
choose HCFC refrigerator, install filter in smoke chimneys

66. CHECK YOUR ANSWER..
Summative
practice
7

67. Nitrogen is
an inactive
gas
Carbon dioxide
important for
photosynthesis
Air also contains
water vapour,
microorganism
and dust

68. Nitrogen
Nitrogen cycle
Helps in animal and
plants growth
Nitric acid and ammonia
Produce nitric acid and
ammonia
Cooling agent

69. Temperature of earth will increase
CONSEQUENCES OF THIS
INTERFERENCE:
1.Global Warming
2.Greenhouse Effect

70. IS AIR A MIXTURE???
YES!!
The components can be separated
by a physical method
(FRACTIONAL DISTILLATION)

71. CARBON
CYCLE
ABSORB CARBON DIOXIDE
- Photosynthesis
RELEASE CARBON DIOXIDE
- Respiration
- Decomposition
- Combustion

72. Inert gas
Helium in hot air
balloon
Argon gas in
light bulb
Neon gas in advertising
light

73. atmosphere
• Layer of air = atmosphere
• Consist of many gases (eg:
nitrogen, oxygen, carbon
dioxide, inert gas)
• Also contain dust,
water vapour, microorganism
AIR

74. oxygen
• Combustion of rocket engine
• Welding and steel cutting • Preparation
of various
compound

75. - green plants are the only living things that can be absorb
and reduce carbon dioxide
- When a lot of trees are cut down, carbon dioxide which
is released through respiration, combustion and
decomposition will increase the percentage of carbon
dioxide in the atmosphere

77. CONSEQUENCES OF
THIS INTERFERENCE:
1.Global Warming
2.Greenhouse Effect

78. Combustion
is when fuel react
with oxygen
chemically and
produce heat and
light energy

79. Safety
measures to
prevent the
occurrence
of fire
Ensure electrical wirings are according
to the right specifications

80. Various substance used
in the fire extinguisher

81. Safety
measures to
prevent the
occurrence
of fire

82. CAUSES AND EFFECTS OF AIR POLLUTION
4. Climate–haze, greenhouse effect, thinning of ozone layer
and acid rain

83. CAUSES AND EFFECTS OF AIR POLLUTION
1. Health problem –breathing difficulties and cough

84. 5. (c) the visiability distance is limited / shorter

85. 6 (a) Caused by natural processes such as
• The decay of organisms (dead bats)
• Respiration of bats/other animals

86. 6 (a) Caused by natural processes such as
• The decay of organisms (dead bats)
• Respiration of bats/other animals
6 (b) • Flame of the torch will extinguish when the
oxygen level is too low
• The use of the torch can warn us not to
continue the exploration

87. 6 (c) No
• Because we don’t know the exact amount of
oxygen in the cave
• The torch will increase the level of carbon
dioxide in the cave

88. 6 (c) No
• Because we don’t know the exact amount of
oxygen in the cave
• The torch will increase the level of carbon
dioxide in the cave
6 (d) • use the oxygen sensor
• We can know the exact level of oxygen and
take precautions

89. 7 (a) • Villagers are concerned about their health
• Quarry project will cause air pollution

90. 7 (a) • Villagers are concerned about their health
• Quarry project will cause air pollution
7 (b) • Job opportunities
• Can earn money

91. 7 (a) • Villagers are concerned about their health
• Quarry project will cause air pollution
7 (b) • Job opportunities
• Can earn money
7 (c) • Yes
• The project can cause health problems to the
villagers

92. 8 (a) • Green plants need light energy for
photosynthesis
• If lack of light, photosynthesis will decrease
• Plants that do not get enough sunlight will die
• Thus, farmers should replace sunlight with
light energy from lamps (suitable intensity)