• MIE Online Grade 9 materials (Link)

• MES Form 3/Grade 9 National exam past papers (Link)

• Chemistry Grade 9 Revision kit (Link)

• Science Grade 9 Ebook (Link)

Notes:

Global Warming:

• Defined as Earth's temperature increase due to rising greenhouse gases.

• Greenhouse gases are heat-trapping gases which include carbon dioxide and methane.

• Methane sources: cattle, decay, landfills.

• Carbon dioxide released from burning fossil fuels.

• Deforestation indirectly raises carbon dioxide levels.

Consequences of Global Warming:

• Coral bleaching

• Glacier melting

• Flooding

• Rising sea levels

• Increased cyclones

• More frequent droughts

• Extinction of species

Combat Measures:

• Burn fewer fossil fuels.

• Use energy-efficient bulbs.

• Plant trees for CO2 absorption.

• Recycle plastic.

• Embrace non-polluting energy and public transport.

Climate Change:

• Abnormal shifts in weather patterns.

Air Pollution:

• Modification of atmospheric characteristics.

• Air pollutants: carbon monoxide, sulfur dioxide, oxides of nitrogen, smoke, CFCs.

Carbon Monoxide:

• Incomplete combustion forms it.

• Poisonous, reduces oxygen transport.

• Symptoms: headaches, vomiting, death.

• Sources: generators, charcoal grills, gas water heaters, vehicle engines.

Sulfur Dioxide:

• Released by factories, vehicles, or volcanic eruptions.

• Reacts with water and oxygen to form sulfuric acid, causing acid rain.

Oxides of Nitrogen:

• Formed in car engines or during lightning.

• React with water and oxygen to form nitric acid, causing acid rain.

Acid rain:

• Harms the environment by eroding limestone structures, corroding steel, acidifying water bodies and soil.

• Adversely affects aquatic life, vegetation, and soil quality.

Smoke:

• Released by vehicles, factories, fires.

• Contains soot and ash.

• Causes suffocation, irritation, and health issues.

CFCs:

• Used in refrigerators, air-conditioners, sprays.

• Deplete ozone layer, leading to UV radiation risks.

• Replaced by ozone-friendly alternatives.

Preventive Measures:

• • Fit catalytic converters in cars for carbon monixide and oxides of nitrogen reduction.

  • Remove sulfur dioxide with calcium carbonate called as desulfurisation.

  • Use gas-water heaters and generators in well ventilate areas.