**Water: The Essence of Life — Quick Summary**
**Key Definitions:**
• Freshwater = water without salt, needed for drinking and life
• Saltwater = ocean water containing salt, not drinkable
• Water cycle = sun heats water → becomes vapour → cools into clouds → falls as rain → cycle repeats
• Groundwater = rainwater stored deep underground in soil and rock layers
• Three forms: solid (ice), liquid (water), vapour (steam/invisible gas)
**Important Facts:**
• Only 5ml of freshwater exists for every 200ml of total Earth water
• Water changes form by heating (liquid→vapour) and cooling (vapour→liquid)
• When sun heats water, it evaporates and rises as invisible vapour
• When vapour cools, it condenses into visible water droplets and clouds
• Rainwater can soak into ground (becoming groundwater) or flow to rivers/oceans
• Wells, borewells, handpumps, and tube wells tap groundwater for villages
**Diagrams to Remember:**
• Water cycle circle: ocean/rivers → evaporation (sun) → clouds → condensation → rain → back to oceans/rivers/ground
• Ice melting to water to steam — showing three forms
• Soil layer showing rainwater soaking down to become groundwater
**Don't Confuse:**
• Ocean water ≠ drinking water (salt makes it undrinkable)
• Water vapour ≠ clouds (vapour is invisible, clouds are visible droplets)
• Melting ≠ disappearing (ice becomes water, still exists)
• Evaporation ≠ boiling (evaporation happens slowly from any surface; boiling is rapid from heat)
Q1. Which of these is freshwater that we can drink?
Answer: A — Well water is freshwater stored underground and free from salt, while ocean and salt pan water contain salt and cannot be drunk.
Q2. If you leave ice in a glass in the sun, what will happen to it?
Answer: B — The sun's heat causes ice (solid form) to melt and change into water (liquid form).
Q3. Water vapour is water in which form?
Answer: C — Water vapour is the invisible gas form of water created when water is heated and evaporates into the air.
Q4. Where does rainwater go after it falls on the ground? (Fill in the blank) Rainwater soaks into the soil and becomes ______.
Answer: B — Rainwater soaks through soil layers and gets stored underground as groundwater, which is tapped by wells and handpumps.
Q5. What does a johad do in villages of Rajasthan?
Answer: B — Johads are traditional small earthen dams that collect and store rainwater, helping water soak into the ground to recharge groundwater supplies.
Q6. If all the water on Earth fit in a big glass, freshwater would only fill _____.
Answer: B — The chapter teaches that freshwater is very scarce — only about a teaspoon out of a full glass of 200ml represents Earth's freshwater.
Q7. Which process is shown when water droplets form on a cold glass in Activity 2?
Answer: B — When cold ice makes the glass cold, water vapour in the air touching the glass cools down and condenses into visible liquid droplets.
Q8. Looking at the water cycle diagram, what causes water to rise from the ocean as vapour?
Answer: C — The sun's heat energy causes water from oceans, rivers, and lakes to evaporate and turn into invisible water vapour that rises into the air.
Q9. Ocean water cannot be used for drinking because it _____.
Answer: B — Saltwater in oceans is not drinkable because the salt makes it unsafe for humans, animals, and plants to consume.
Q10. How is groundwater useful to villages without rivers nearby?
Answer: B — Groundwater stored underground can be accessed by digging wells, borewells, and handpumps, giving villages a reliable water source even without nearby rivers.
What is freshwater?
Water without salt that humans, animals, and plants can drink and use for living.
Name the three forms of water.
Solid (ice), liquid (water), and vapour (steam).
What is the water cycle?
The constant circular movement where water evaporates into vapour, forms clouds, falls as rain, and returns to oceans and rivers.
How much of Earth's water is freshwater?
Only about a teaspoon full out of a full glass — most water on Earth is salty ocean water.
What is groundwater?
Water that soaks through soil and rocks and gets stored deep underground in layers below the surface.
Name three ways to get groundwater.
Wells, borewells, tube wells, and handpumps are dug deep into ground to draw out water.
What happens when ice is left in sunlight?
Ice melts and turns into liquid water because heat energy from the sun makes the solid form change.
What are johads?
Traditional small earthen dams built in Rajasthan to collect rainwater and refill the water underground.
Why do water droplets form on a cold glass?
Water vapour in the air touches the cold glass and cools down, changing from invisible gas to visible liquid droplets.
Name two freshwater sources found near homes or villages in India.
Lakes, rivers, wells, borewells, handpumps, ponds, and tanks that collect rainwater.
What is freshwater? Name one place near your home where you can find freshwater. [1 mark]
Define freshwater as water without salt. Give any local example: well, tap, lake, river, handpump, or tank.
Draw and label the three forms of water. Write one sentence about each. [2 marks]
Draw ice (solid), water in cup (liquid), and steam from pot (vapour/gas). Label each and write: solid is hard, liquid flows, vapour is invisible gas.
Explain with an example how the water cycle works in nature. What role does the sun play? [3 marks]
Describe: sun heats water (evaporation) → water becomes vapour and rises → cools to form clouds (condensation) → falls as rain → returns to rivers/oceans. Example: rain falling, soaking into ground, or flowing to rivers.
What is groundwater? How do people in villages use groundwater? Draw a simple diagram showing how rainwater becomes groundwater. [5 marks]
Define: water stored deep underground in soil and rock layers. Uses: drinking from wells, handpumps, borewells, tube wells. Diagram: show rain falling → soaking through soil layers → collecting underground below roots. Label: rain, soil, rocks, groundwater, well/handpump.
True or False: Ocean water can be used for drinking. Write one reason for your answer. [2 marks]
Answer: False. Reason: Ocean water contains salt, making it undrinkable for humans, animals, and plants. Only freshwater without salt is safe to drink.
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