Water — Study Notes for Bihar TET Paper I (EVS)

Overview

Water is a foundational topic in Environmental Studies for Bihar TET Paper I, connecting science concepts with daily life and local environment. This topic tests your understanding of where water comes from, how to conserve and purify it, and the diseases caused by contaminated water — all framed within the primary-school teaching context.

Bihar's geography makes this topic especially relevant. The state is drained by major rivers like Ganga, Kosi, Gandak and Son, yet faces both floods and water scarcity in different seasons. Questions often link textbook concepts to Bihar's water reality — groundwater depletion, flood-prone areas and safe drinking water access in rural communities.

For the exam, focus on practical knowledge that a primary teacher would use: explaining the water cycle to children, teaching water-saving habits, and creating awareness about waterborne diseases. Expect 2–4 questions from this sub-topic, often scenario-based or linked to classroom teaching situations.

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Key Concepts

• **Three states of water**: Water exists as solid (ice), liquid (water) and gas (water vapour). Children observe all three in daily life — ice cubes, drinking water, steam from cooking.

• **Water cycle (Hydrological cycle)**: Evaporation → Condensation → Precipitation → Collection. This continuous cycle ensures water renewal on Earth. Key terms: evaporation (water to vapour), condensation (vapour to droplets), precipitation (rain/snow/hail).

• **Sources of water**: Surface water (rivers, lakes, ponds, reservoirs) and groundwater (wells, tubewells, handpumps). Rainwater is the primary source replenishing both.

• **Potable vs non-potable water**: Potable water is safe for drinking. Only about 1% of Earth's water is freshwater accessible for human use.

• **Water conservation**: Reducing wastage, rainwater harvesting, recharging groundwater, repairing leaks, and using water-efficient practices.

• **Water purification methods**: Boiling, filtration, chlorination, use of alum (phitkari), and modern RO/UV systems. Primary schools focus on simple household methods.

• **Waterborne diseases**: Diseases spread through contaminated water — caused by bacteria, viruses, parasites entering the digestive system.

• **Bihar context**: Rivers like Ganga, Kosi, Gandak are lifelines; arsenic contamination in groundwater is a serious issue in several Bihar districts.

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Key Facts to Remember

| Fact | Detail | |------|--------| | Earth's water coverage | About 71% of Earth's surface is water | | Freshwater percentage | Only about 3% of total water is freshwater; most is in glaciers | | Safe drinking water | Less than 1% of Earth's water is accessible freshwater | | Boiling time for purification | Water should be boiled for at least 10–20 minutes to kill germs | | Chlorine for purification | 2–3 drops of liquid chlorine per litre of water | | Alum (Phitkari) use | Settles suspended impurities; does not kill germs | | World Water Day | 22 March | | Major rivers of Bihar | Ganga, Kosi, Gandak, Son, Bagmati, Punpun | | Arsenic-affected districts | Parts of Bhojpur, Bhagalpur, Patna, Vaishali and others |