Extra 20 important long questions and answers from Chapter:14 Water of Class 6 Science (CBSE):-
1. What is the water cycle? Explain its main processes.
Answer: The water cycle is the continuous movement of water on Earth through different processes. The main processes are:
Evaporation
– Water from oceans, lakes, and rivers changes into water vapor due to heat.
Transpiration
– Plants release water vapor into the atmosphere.
Condensation
– Water vapor cools down and forms tiny droplets, leading to cloud formation.
Precipitation
– Clouds become heavy and release water as rain, snow, or hail.
Infiltration
– Some rainwater seeps into the ground and replenishes groundwater.
Collection
– Water collects in rivers, lakes, and oceans, completing the cycle.
2. Explain the different forms of water found on Earth.
Answer: Water exists in three forms on Earth:
Solid (Ice)
– Found in glaciers, polar ice caps, and snow-covered mountains.
Liquid (Water)
– Found in oceans, rivers, lakes, ponds, and underground water.
Gas (Water Vapor)
– Present in the atmosphere and forms clouds.
Dew and Frost
– Water vapor condenses to form dew on cool surfaces and frost in colder conditions.
Fog and Mist
– Tiny water droplets suspended in the air, reducing visibility.
Clouds
– Formed when water vapor condenses at high altitudes.
3. What is evaporation? What are the factors affecting it?
Answer: Evaporation is the process in which liquid water changes into water vapor due to heat. The factors affecting evaporation are:
Temperature
– Higher temperatures increase evaporation.
Surface Area
– More surface area allows faster evaporation.
Wind Speed
– Strong winds carry away water vapor, increasing evaporation.
Humidity
– Lower humidity increases evaporation.
Nature of Liquid
– Pure water evaporates faster than solutions.
Pressure
– Lower atmospheric pressure increases evaporation.
4. What is condensation? Give examples from daily life.
Answer: Condensation is the process in which water vapor cools down and turns into liquid water. Examples include:
Formation of Dew
– Water droplets form on grass and leaves in the early morning.
Cloud Formation
– Water vapor condenses at high altitudes to form clouds.
Fog Formation
– Water vapor near the ground condenses into tiny water droplets.
Water Droplets on a Cold Glass
– When a cold glass is placed in warm air, water condenses on it.
Steam on Bathroom Mirror
– Hot shower steam condenses on the mirror surface.
Droplets on Car Windows
– Seen during winter or in air-conditioned cars.
5. What are the main sources of water on Earth?
Answer: The major sources of water on Earth are:
Oceans and Seas
– Cover about 71% of the Earth's surface but contain salty water.
Rivers and Lakes
– Provide fresh water for drinking, irrigation, and industries.
Glaciers and Ice Caps
– Store about 69% of the Earth’s freshwater in solid form.
Rainwater
– A natural source of fresh water replenishing rivers and lakes.
Groundwater (Wells and Springs)
– Water stored underground, used for drinking and irrigation.
Dams and Reservoirs
– Artificial water storage systems for electricity and irrigation.
6. What are the main causes of water pollution?
Answer: Water pollution is caused by:
Industrial Waste
– Chemicals and toxins from factories pollute rivers and lakes.
Sewage Disposal
– Untreated waste from households and cities contaminates water.
Agricultural Runoff
– Pesticides and fertilizers mix with water sources.
Oil Spills
– Leaks from ships and oil refineries harm marine life.
Plastic Waste
– Non-biodegradable waste clogs water bodies and harms aquatic organisms.
Mining and Deforestation
– Soil erosion and heavy metals pollute rivers and lakes.
7. What are the effects of water pollution?
Answer: Water pollution has serious consequences:
Diseases
– Causes cholera, typhoid, and dysentery.
Harm to Aquatic Life
– Polluted water kills fish and other aquatic organisms.
Loss of Drinking Water
– Polluted rivers and lakes reduce the availability of clean water.
Soil Contamination
– Polluted water affects agriculture.
Damage to Ecosystem
– Harms plants, animals, and the food chain.
Air Pollution
– Contaminated water can release harmful gases.
8. How can we conserve water?
Answer: Water conservation methods include:
Rainwater Harvesting
– Collecting rainwater for use.
Fixing Leaks
– Prevents water wastage.
Using Water-efficient Appliances
– Saves water at home.
Recycling Water
– Treating and reusing wastewater.
Growing Drought-resistant Crops
– Reduces agricultural water use.
Public Awareness
– Educating people about water conservation.
9. Why is groundwater important?
Answer: Groundwater is crucial because:
Provides Drinking Water
– Major source for many cities and villages.
Used in Agriculture
– Essential for irrigation.
Industrial Use
– Factories use it for cooling and processing.
Maintains Water Cycle
– Supports rivers during dry seasons.
Less Pollution
– Naturally filtered through soil.
Emergency Resource
– Available even in drought conditions.
10. How do floods occur? What are their effects?
Answer: Floods occur due to:
Heavy Rainfall
– Excessive rain causes rivers to overflow.
Deforestation
– Reduces water absorption, increasing surface runoff.
Melting Glaciers
– Increases water levels in rivers.
Dams Breaking
– Releases a large volume of water suddenly.
Urbanization
– Reduces soil absorption capacity.
Tsunamis
– Cause coastal flooding.
Effects of floods:
Loss of Life and Property
– Destroys homes, roads, and bridges.
Waterborne Diseases
– Contaminated water spreads diseases.
Soil Erosion
– Washes away fertile topsoil.
Loss of Crops
– Damages agriculture.
Economic Loss
– Affects businesses and livelihoods.
Displacement of People
– Many people become homeless.
11. What are the effects of water scarcity?
Answer: Water scarcity affects humans, animals, and the environment in many ways:
Reduced Drinking Water
– Limited availability of clean water for drinking.
Agricultural Loss
– Crops fail due to lack of irrigation, leading to food shortages.
Health Issues
– Dirty water causes diseases like cholera and dysentery.
Economic Impact
– Industries and farming suffer, leading to unemployment.
Environmental Damage
– Droughts harm plants and animals.
Conflicts Over Water
– Water shortage can cause disputes between regions and countries.
12. How does deforestation affect the water cycle?
Answer: Cutting down trees (deforestation) negatively impacts the water cycle in the following ways:
Less Transpiration
– Reduces water vapor released by plants, affecting rainfall.
Less Rainfall
– Leads to drier climates and droughts.
Soil Erosion
– Without trees, rainwater washes away fertile soil.
Flooding
– Trees help absorb water; without them, floods occur more frequently.
Groundwater Depletion
– Fewer trees mean less water seeps into the ground.
Loss of Biodiversity
– Affects plants, animals, and
humans
dependent on forests.
13. How does human activity impact water availability?
Answer: Human activities affect water availability in the following ways:
Excessive Water Use
– Overuse in industries, farming, and homes leads to depletion.
Deforestation
– Reduces rainfall and groundwater recharge.
Pollution
– Industrial waste, sewage, and plastic waste contaminate water sources.
Urbanization
– Increases demand for water while reducing absorption areas.
Climate Change
– Alters rainfall patterns, leading to droughts or floods.
Groundwater Overuse
– Excessive use of borewells lowers the water table.
14. What are the advantages of rainwater harvesting?
Answer: Rainwater harvesting is a method of collecting and storing rainwater for future use. Its benefits include:
Increases Water Supply
– Provides water for drinking, irrigation, and household use.
Reduces Groundwater Use
– Lessens the pressure on underground water sources.
Prevents Water Wastage
– Captures rainwater that would otherwise flow away.
Reduces Soil Erosion
– Controls excessive water runoff.
Minimizes Flooding
– Helps manage excess rainwater in urban areas.
Low-cost and Sustainable
– Requires minimal investment and benefits communities.
15. How can industries reduce water pollution?
Answer: Industries can take the following steps to reduce water pollution:
Proper Waste Treatment
– Factories should treat wastewater before releasing it.
Use of Eco-friendly Chemicals
– Reduces harmful pollutants in water.
Recycling Water
– Industries should reuse water where possible.
Reducing Chemical Spillage
– Proper handling and storage of chemicals.
Encouraging Public Awareness
– Educating workers on water conservation.
Following Government Regulations
– Adhering to pollution control laws.
16. How does water pollution affect aquatic life?
Answer: Water pollution has harmful effects on aquatic organisms:
Reduces Oxygen Levels
– Pollutants deplete oxygen, suffocating fish.
Kills Marine Life
– Harmful chemicals cause mass fish deaths.
Bioaccumulation
– Toxins accumulate in fish and harm predators, including humans.
Destroys Coral Reefs
– Chemicals and plastics damage marine ecosystems.
Spreads Diseases
– Polluted water spreads infections among aquatic animals.
Algae Bloom
– Excess nutrients cause uncontrolled algae growth, harming fish.
17. Explain the importance of groundwater.
Answer: Groundwater plays a crucial role in sustaining life and the environment:
Drinking Water Source
– Used by millions worldwide.
Supports Agriculture
– Essential for irrigation in dry areas.
Maintains River Flow
– Feeds rivers and lakes during dry seasons.
Less Affected by Pollution
– Naturally filtered by soil and rocks.
Disaster Resilience
– Used in droughts and emergencies.
Industrial Use
– Factories depend on groundwater for production.
18. How does excessive water use affect the environment?
Answer: Overuse of water leads to several environmental problems:
Groundwater Depletion
– Overdrawing from wells lowers the water table.
Droughts
– Excessive irrigation and urban use cause water shortages.
Destruction of Aquatic Ecosystems
– Rivers and lakes dry up, affecting wildlife.
Soil Salinity
– Over-irrigation leads to salt
buildup
, harming crops.
Energy Waste
– Pumping excessive water increases energy consumption.
Decline in Biodiversity
– Plants and animals suffer due to reduced water availability.
19. What happens when we waste water?
Answer: Wasting water has serious consequences:
Water Shortage
– Future generations may face severe scarcity.
Increased Bills
– Higher water usage means more expenses for households.
Damage to Ecosystem
– Rivers and lakes dry up, affecting plants and animals.
Reduced Agricultural Productivity
– Crops fail due to lack of water.
Pollution and Health Issues
– Less clean water leads to increased diseases.
Impact on Climate
– Imbalance in the water cycle affects weather patterns.
20. How does climate change impact the water cycle?
Answer: Climate change affects the water cycle in various ways:
Changes in Rainfall Patterns
– Some regions experience heavy rains, while others face droughts.
Faster Evaporation
– Rising temperatures increase water loss from lakes and soil.
Melting Glaciers
– Causes sea level rise and loss of freshwater reserves.
Stronger Storms and Floods
– More intense rainfall leads to disasters.
Groundwater Depletion
– Less rain reduces water seepage into the ground.
Loss of Biodiversity
– Many plants and animals struggle to survive in changing conditions.
