- Chapter 1 – Nutrients in plants
- Chapter 2 – Nutrition in Animals
- Chapter 3 – Fibre to Fabric
- Chapter 4 – Heat
- Chapter 5 – Acids bases and salts
- Chapter 6 – Physical and Chemical Changes
- Chapter 7 – Weather, Climate and Adaptations of Animals to Climate
- Chapter 8 – Winds, Storms and Cyclone
- Chapter 9 – Soil
- Chapter 10 – Respiration in Organisms
- Chapter 11 – Transportation in Animals and Plants
- Chapter 12 – Reproduction in Plants
- Chapter 13 – Motion and Time
- Chapter 14 – Electric Current and its Effects
- Chapter 15 – Light
- Chapter 16 – Water: A Precious Resource
- Chapter 17 – Forests: Our Lifeline
- Chapter 18 – Waste water Story
- Question Bank – Chapter 1 – Nutrients in Plants
- Question Bank – Chapter 2 – Nutrition in Animals
- Question Bank – Chapter 3 – Fibre to Fabric
- Question Bank – Chapter 4 – Heat
- Question Bank – Chapter 5 – Acids, Bases and Salts
- Question Bank – Chapter 6 – Physical & Chemical Changes
- Question Bank – Chapter 7 – Weather, Climate & Adaptations of Animals to Climate
- Question Bank – Chapter 8 – Winds, Storms and Cyclones
- Question Bank – Chapter 9 – Soil
- Question Bank – Chapter 10 – Respiration in Organisms
- Question Bank – Chapter 11 – Transportation in Animals and Plants
- Question Bank – Chapter 12 – Reproduction in Plants
- Question Bank – Chapter 13 – Motion and Time
- Question Bank – Chapter 14 – Electric Current & Its Effects
- Question Bank – Chapter 15 – Light
- Question Bank – Chapter 16 – Water: A Precious Resoure
- Question Bank – Chatper 17 – Forest: Our Life Line
- Question Bank – Chapter 18 – Waste Water Story
Question Bank – Chapter 16 – Water: A Precious Resoure
Water: A Precious Resource
Q1. Why and when world water day is celebrated?
Ans. 22 March is celebrated as the world water day to attract the attention towards the importance of conserving water.
Q2. How much water is available on Earth, is all water useful?
Ans. About 71% of the earth’s surface is covered with water. Almost all the water on the earth is contained in the seas and oceans, most of this water is not fit for consumption only freshwater is fit for use.
Q3. Explain how groundwater is recharged?
Ans. The rainwater and water from other sources such as rivers and ponds seeps through the soil and fills the empty spaces and cracks, it is called infiltration groundwater thus gets recharged by this process.
Q4. What do you understand by the term water harvesting?
Ans. Rainwater collected from roof can be used to recharge the groundwater this is referred to as water harvesting or rainwater harvesting,
Q5. What is drip irrigation, is it useful?
Ans. Drip irrigation is a technique of watering plants by making use of narrow tubings which deliver water directly at the base of the plant, it is very useful to save water.
Q6. What should be done to save water?
Ans. We should stop wastage during the supply of water through pipes, the leaking taps in buildings and other places. Unnecessary use of water and overdrawing from groundwater should be avoided and Recharge of water to the ground should be increased.
Q7. Explain the factors responsible for the depletion of water .
Ans. Rapid growth of industries, increasing population, growing irrigation requirements and mismanagement are the causes for water shortage, deforestation and decrease in the effective area for seepage of water are also responsible.
Q.8 What will be the ultimate effect of “no water” to plants?
Ans. If water is not available to plants the green character of the planet shall be lost. This may mean the end of all life, no food, no oxygen, not enough rain, and innumerable other problems.
Q9. What is water table?
Ans. A level where all the space between particles of soil and gaps between rocks are filled with water is called the water table.
Q 10. What is the cause of water table going down?
Ans. Water drawn from under the ground gets replenished by seepage of rainwater. The water table does not get affected as long as we draw as much water as is replenished by natural processes water table may go down if the water is not sufficiently replenished.