CBSE Class 6 Science Water Worksheet Set 06

ANSWER THE FOLLOWING:

Question 1. Name 2 ways by which water vapour gets added to air.
Answer: Water vapour gets added to the air mainly through two processes: (1) Evaporation of water from oceans, rivers, lakes, and soil due to heat from the sun, and (2) Transpiration, which is the release of water vapour by plants into the atmosphere.
In simple words: Water enters the air when it evaporates from wet surfaces and when plants release it.

Exam Tip: Remember the two key biological and physical processes: evaporation and transpiration.

Question 2. What is meant by rainwater harvesting? What is the basic idea behind rainwater harvesting?
Answer: Rainwater harvesting is the process of collecting rainwater from rooftops or open areas and storing it for future use or allowing it to seep into the ground to recharge groundwater levels. The basic idea behind rainwater harvesting is "catch water where it falls" to conserve water resources and improve groundwater storage.
In simple words: Collecting and storing rain for later use instead of letting it run off wastefully.

Exam Tip: Always mention both parts: collection and underground recharge for complete credit.

Question 3. What is groundwater? Name 2 sources of groundwater.
Answer: Groundwater is the water that seeps deep into the earth through the soil and collects in spaces and cracks in underground rocks. Two main sources of groundwater are wells and tube wells (or handpumps and springs).
In simple words: Water stored underground beneath the soil surface.

Exam Tip: Clearly state that it is found beneath the Earth's surface in the soil and rock layers.

Question 4. When does a drought occur?
Answer: A drought occurs when an area receives little to no rainfall for a very long period. During this time, water evaporates continuously from soil and plants due to heat, but is not replenished by rain, leading to severe water scarcity.
In simple words: Lack of rain for a long time causes drought and water shortages.

Exam Tip: Mention the key condition: failure of rain for an extended period.

Question 5. Areas of land which is covered with concrete affects the availability of groundwater. Why?
Answer: Concrete makes the ground surface impermeable, meaning rainwater cannot seep through it into the soil. As a result, rainwater runs off into drains instead of recharging the groundwater table, leading to a decrease in groundwater availability.
In simple words: Concrete blocks rain from sinking into the ground, reducing underground water.

Exam Tip: Use the scientific term 'impermeable surface' to score full marks.

FILL IN THE BLANKS:

Question 1. ________, ________ and ________ replenish water in rivers, ponds wells and soil.
Answer: Rain, snow, hail (or Rain, snowfall, melting snow)
In simple words: Precipitation in various forms refills water bodies.

Exam Tip: Recall sources of natural water precipitation.

Question 2. Most of the rainwater becomes available to us as ________.
Answer: groundwater
In simple words: Rain sinks into the earth and becomes underground water.

Exam Tip: Link rainwater to underground storage aquifers.

Question 3. ________________________ maintains the supply of water on land.
Answer: Water cycle (or Rain / The water cycle)
In simple words: The continuous movement of water keeps water supplied on Earth.

Exam Tip: The water cycle is nature's recycling system for water.

Question 4. Watervapour gets added to air by ________ and ________.
Answer: evaporation, transpiration
In simple words: Water turns to gas from wet things and plants.

Exam Tip: These are the two primary vapor-adding mechanisms.

Question 5. ________________________ is essential to convert water into its vapour.
Answer: Heat (or Sunlight / Energy)
In simple words: Heat is needed to change liquid water into gas.

Question 6. Fog appearing on a cold winter morning is due to ________.
Answer: condensation
In simple words: Water vapour condenses on dust particles in cold air.

Exam Tip: Cold temperatures cause water vapour to condense into tiny droplets.

NAME THE FOLLOWING:

Question 1. The process of changing watervapour into water-
Answer: Condensation
In simple words: Gas turning back into liquid water.

Exam Tip: Opposite of evaporation.

Question 2. The circulation of water between ocean and land -
Answer: Water cycle (or Hydrological cycle)
In simple words: The endless journey of water between earth and sky.

Exam Tip: Encompasses evaporation, condensation, precipitation, and collection.

Question 3. Collecting rain water for future use-
Answer: Rainwater harvesting
In simple words: Saving rainwater instead of letting it waste.

Question 4. The drops of water falling from the clouds-
Answer: Rain
In simple words: Water falling from the sky.

Exam Tip: Form of precipitation.

Question 5. The release of watervapour into the air by the plants-
Answer: Transpiration
In simple words: Plants losing water through tiny leaf pores.

Exam Tip: Occurs mainly through stomata on leaves.

Question 6. Define : a) evaporation b) condensation c) Transpiration
Answer:
a) Evaporation: The process in which liquid water changes into water vapour (gas) due to heat.
b) Condensation: The process in which water vapour (gas) cools down and changes back into liquid water droplets.
c) Transpiration: The process by which plants absorb water from the soil and release excess water in the form of water vapour through their leaves.
In simple words: Evaporation turns water to gas, condensation turns gas to liquid, and transpiration is water loss from plants.

Exam Tip: Learn these three definitions thoroughly as they form the core of the chapter.

CHOOSE THE CORRECT ANSWER:

Question 1. Lack of rains for long periods may cause
(a) floods
(b) droughts
(c) precipitation
Answer: (b) droughts
Absence of rainfall over a long duration causes severe water scarcity and dries up soil, leading to a drought.
In simple words: No rain means drought.

Exam Tip: Drought is the exact opposite of flood.

Question 2. Higher temperature in the air
(a) decreases the rate of evaporation
(b) increases the rate of evaporation
(c) causes no change in the rate of evaporation
Answer: (b) increases the rate of evaporation
Higher temperature provides more thermal energy, causing water molecules to convert into vapour faster.
In simple words: More heat makes water evaporate quicker.

Question 3. Most of the rainfall occurs during this season.
(a) summer
(b) winter
(c) monsoon
Answer: (c) monsoon
Monsoon is the designated rainy season in regions like India, bringing the majority of annual rainfall.
In simple words: Monsoon brings most of the rain.

Exam Tip: Monsoon winds carry moisture-laden clouds from oceans to land.

Question 4. As we go higher from the surface of the earth, it gets
(a) hotter
(b) cooler
(c) no change in temperature
Answer: (b) cooler
As altitude increases, atmospheric pressure decreases, causing the air temperature to drop.
In simple words: Higher altitude means colder air.

Question 5. Steam rising from wet clothes while they are ironed, is due to
(a) condensation
(b) evaporation
(c) precipitation
Answer: (b) evaporation
The high heat from the iron rapidly converts the moisture in the wet clothes into water vapour (steam).
In simple words: Heat from the iron turns water in clothes into steam quickly.

Exam Tip: Rapid evaporation is triggered by intense heat sources like a hot iron.

WRITE TRUE OR FALSE. IF FALSE, REWRITE THE CORRECT STATEMENT

Question 1. The process of changing water to its vapour is called condensation.____________________
Answer: False.
Correct statement: The process of changing water to its vapour is called evaporation.
In simple words: Water turning into vapour is evaporation, not condensation.

Exam Tip: Always double-check direction: liquid-to-gas is evaporation, gas-to-liquid is condensation.

Question 2. Excessive rains may cause droughts.____________________
Answer: False.
Correct statement: Excessive rains may cause floods.
In simple words: Too much rain causes floods, not droughts.

Question 3. In sunlight evaporation takes place slower.____________________
Answer: False.
Correct statement: In sunlight evaporation takes place faster.
In simple words: Sunlight speeds up evaporation because it provides heat.

Exam Tip: Sunlight and heat accelerate the evaporation process.

Question 4. Blackboard dries up after wiping it, is due to condensation____________________
Answer: False.
Correct statement: Blackboard dries up after wiping it, is due to evaporation.
In simple words: Water on the blackboard evaporates into the air.

Exam Tip: Drying of wet surfaces is always due to evaporation.

Question 5. The cold surface of the glass containing iced water, cools the air around it.____________________
Answer: True.
In simple words: Cold glass lowers the temperature of the air touching it.

Exam Tip: This cooling of surrounding air is what leads to water droplets forming on the outer glass surface.