🌿 Natural Resources – Class 9 Science

Natural resources

Resources found in nature used by living beings for survival

Atmosphere

Layer of air surrounding Earth

Hydrosphere

All water bodies on Earth (oceans

Lithosphere

Earth's solid outer layer (land

Biosphere

Zone of life on Earth where living organisms interact with air

Air composition

Nitrogen (78%)

Carbon dioxide role

Used by plants for photosynthesis

Oxygen role

Used in respiration and combustion

Air pollution

Contamination of air by harmful substances (e.g.

Greenhouse effect

Trapping of heat by CO₂

Global warming

Gradual increase in Earth's temperature due to greenhouse gases

Water cycle

Continuous movement of water through evaporation

Evaporation

Conversion of water to vapour due to heat

Condensation

Cooling of water vapour into liquid form (cloud formation)

Precipitation

Falling of water droplets as rain

Rainwater harvesting

Collecting rainwater for reuse and groundwater recharge

Water pollution

Contamination of water by domestic

Ozone

O₃ gas in the stratosphere that absorbs harmful UV radiation

Ozone layer depletion

Thinning of ozone due to CFCs

Smog

Mix of smoke and fog

Nitrogen cycle

Cyclic process of converting nitrogen into usable forms and returning it to the atmosphere

Nitrogen fixation

Conversion of nitrogen gas into nitrates by bacteria or lightning

Nitrification

Conversion of ammonia into nitrites and then nitrates

Denitrification

Conversion of nitrates back into nitrogen gas by bacteria

Ammonification

Conversion of dead plants/animals into ammonia

Carbon cycle

Cyclic process of carbon exchange between organisms

Photosynthesis

Process by which plants use CO₂ and sunlight to make food

Respiration

Process by which organisms release CO₂ by breaking down food

Combustion

Burning of fuels releasing CO₂

Deforestation

Cutting of trees

Water as a resource

Essential for life

Soil erosion

Wearing away of topsoil due to wind or water

Soil formation

Process by which rocks break down to form soil

Soil pollution

Presence of toxic chemicals in soil

Biogeochemical cycles

Natural cycles of water

Oxygen cycle

Movement of oxygen between atmosphere

Green plants role

Absorb CO₂ and release oxygen during photosynthesis

Aquatic ecosystem

Ecosystems in water bodies like rivers

Algal bloom

Overgrowth of algae due to excess nutrients (causes water pollution)

Fossil fuels

Coal

Air pollutants

SO₂

Eutrophication

Enrichment of water bodies with nutrients causing excessive algae growth

Renewable resources

Resources that are replenished naturally (e.g.

Non-renewable resources

Resources that take millions of years to form (e.g.

Acid rain

Rain containing acids formed from sulfur and nitrogen oxides

Afforestation

Planting trees to restore forests and improve environment