Science (Air Around Us) Part - 2
Science (Air Around Us) (Part 1 & Part 2) Covers the Following Topics
1. Introduction to Air
- Air is essential for all living beings.
- Examples of air’s presence:
- Leaves rustling.
- Clothes swaying on a line.
- Kites flying.
- Activities:
- Making a firki to observe air movement.
- Using a weathercock to identify wind direction.
2. Air’s Ubiquity
- Air is present everywhere.
- Demonstration of air occupying space:
- Inverted bottle experiment.
- Observation of bubbles when air is displaced by water.
- Explanation:
- Air is transparent and colorless.
- The atmosphere surrounds Earth and becomes rarer at higher altitudes.
3. Composition of Air
- Air is a mixture of gases:
- Nitrogen (78%)
- Oxygen (21%)
- Carbon dioxide (0.03%)
- Water vapor
- Dust particles
- Activities:
- Burning a candle in a closed jar to observe oxygen consumption.
- Observing sunlight beams to detect dust particles.
- Explanation of components:
- Role of oxygen in combustion and respiration.
- Nitrogen’s dominance but non-reactive nature.
- Carbon dioxide’s role in photosynthesis and its production during respiration and combustion.
- Importance of water vapor in the water cycle.
4. Air in Soil
- Presence of air in soil:
- Observed by immersing soil in water and observing bubbles.
- Explanation:
- Air supports the respiration of organisms in the soil.
- Waterlogged soil during heavy rains forces organisms like earthworms to surface.
5. Air in Water
- Dissolved air in water:
- Observed as bubbles escaping during heating.
- Role in aquatic life:
- Dissolved oxygen is critical for respiration in aquatic animals and plants.
6. Role of Air in Photosynthesis
- Oxygen production and carbon dioxide absorption during photosynthesis.
- Role of plants in maintaining oxygen and carbon dioxide balance.
- Interdependence of plants and animals:
- Plants produce oxygen; animals produce carbon dioxide.
7. Uses of Air
- Air supports:
- Windmill operation for electricity and water pumping.
- Sailing and flying (parachutes, gliders, and planes).
- Dispersal of seeds and pollen.
- Role in the water cycle:
- Facilitates evaporation and condensation.
8. Air Pollution
- Causes:
- Burning fuels and biomass (e.g., dry leaves, crops).
- Emission of harmful gases and smoke.
- Effects:
- Dust and soot on roadside plants.
- Respiratory problems in humans and animals.
- Pollution’s spread through tall chimneys.
- Observing dust deposition on windows and plants near roads.
- Investigating soot levels in different locations.
- Monitoring dust particle variation over time.
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