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Water is an important aspect of life. Without water no organisms can survive. Around 70% of the Earth is covered with water. We use water in almost everything that we do. Understanding the science behind the formation of water , it’s nature and the way it interact with every other water is very important. Human body, though looks like a solid has more than half of water in the form of plasma, blood, lymph, tears etc. Water is well known as an universal solvent because of its ability to easily dissolve many solids, liquids and gases present around us. In this lesson, we will understand some basic information about water such as its sources, Chang of its state, uses etc.

I. Important question answers

1. Where do we get water from?

Answer: Rain is the ultimate source of water. Other important sources are; ponds, underground water, canals, and rivers .

2. Explain the water cycle briefly.

Answer: Water cycle, or hydrological cycle, is the movement of water above, and below the Earth's surface. Some of the phases of water cycle are as follows:

1. Evaporation helps water from oceans, lakes, and rivers turns intorvapor with the help of Sun’s heat.
2. Transpiration occur due to the loss of water from the surface of leaves.
3. Condensation is the act of turning water into clouds by cooling.
4. Precipitation lead to water to fall as rain, snow, sleet, or hail.
5. Infiltration is a process where water flows into rivers, lakes, and oceans or soaks into the ground to replenish groundwater

3. Explain the water loss mechanism from plants and animals .

Answer: Water loss in Plants occurs through transportation, guttation, and evaporation.Water loss in plants and animals occurs as follows

Water loss in plants

In transpiration – Water evaporates from leaves through stomata. In Guttation, , lossof water occur in liquid form from leaf edges. In the case of evaporation –, there is direct water loss from plant surfaces.

Water loss in plants

Animals lose water by sweating, excretion, breathing and injuries. Sweating is the evaporation as a defence mechanism to heat . This helps in the regulatiion of body temperature. Animals lose water through respiration . Excretion in animals allows easy passage of urine and faeces along with water. in it. Some serious injuries also cause water loss due to excess of bleeding.

4. Explain the clouds formation?

Answer: Cloud formation is a cycle that involves:

1. Evaporation – Water from oceans, lakes, and plants turns into water vapor.
2. Rising Air – Warm air carrying water vapor rises due to convection, wind, or topography.
3. Cooling & Condensation – As the air rises, it cools, and the water vapor condenses around dust or pollen, forming tiny water droplets or ice crystals.
4. Cloud Formation – These droplets cluster together, creating visible clouds

5. How can we conserve water, explain?

Answer :

1. We must reduce Wastage of water by repairing leaking taps. Make sure to turn off taps when not in use, and use water-efficient appliances.
2. Use efficient irrigation methods such as drip irrigation, and sprinle irrigation. Households can adapt rainwater harvesting.
3. Reuse Water for gardening and cleaning.
4. Rainwater Harvesting helps to collect and store rainwater for later use.
5. Educate people about the importance of water conservation and encourage sustainable practices

6. When does a drought occur?

Answer: If it does not rain for two or more years, water is lost from the soil due to evaporation and transpiration. Since it is not being brought back by rain, the soil becomes dry. The level of water in ponds and wells of the region goes down, and some of them may even dry up. Groundwater may also become scarce; this may lead to drought.

7. Suppose you want to dry your school uniform quickly. Would spreading it near an anghiti or heater help? If yes, how?

Answer: Spreading uniform near an anghiti or heater will help because it increases the rate of evaporation due to heat.

8. Take out a cooled bottle of water from the refrigerator and keep it on a table. After some time, you notice droplets of water around it. Why

Answer: This is because the surface of the air around the bottle cools down and air condenses around the bottle.

9. To clean their spectacles, people often breathe out on glasses to make them wet. Explain why the glasses become wet.

Answer: The air we breathe out contains water vapour which condenses on the surface of the spectacles. So, the glass becomes wet, and with the help of a small number of water molecules, it becomes easier to clean the spectacles

II. Fill in the blanks :

1. 1. The process of changing of water into its vapour is calledvaporization .
   2. The process of changing water vapour into water is called condensation
   3. No rainfall for a year or more may lead to droughtin that region
   4. Excessive rains may cause floods.
   5. Rainy season is called
   6. Saline water is found in oceans.

III. State for each of the following whether it is due to evaporation or condensation.

1. Water drops appear on the outer surface of a glass containing cold water( condensation) .
2. Steam rising from wet clothes while they are ironed( Evaporation).
3. Fog appearing on a cold winter morning.( Condensation)
4. Blackboard dries up after wiping it.
5. Steam rising from a hot girdle when water is sprinkled on it( Evaporation).

IV. State true or false

1. Water vapour is present in the air only during the monsoon.
2. Water evaporates into the air from oceans, rivers and lakes but not from the soil.
3. The process of water changing into its vapour is called evaporation.
4. The evaporation of water takes place only in sunlight.
5. Water vapour condenses to form tiny droplets of water in the upper layers of air where it is

V. Additional questions and answers

1. What are the three main states of water in the water cycle?
   Answer: Solid (ice), liquid (water), and gas (water vapor).
2. How does groundwater get replenished?
   Answer: Ground water gets recharged or replenished by the infiltration, where rainwater or melted snow seeps into the soil to get into the underground reservoirs.
3. Distinguish between evaporation and condensation?
   Answer: Evaporation is the process where water turns into vapor, while condensation is when water vapor cools and turns back into liquid.
4. Why is groundwater very important?
   Answer: It is a major source of drinking water and supports ecosystems.
5. What is water pollution How are we polluting water?
   Answer: Industrial waste disposal, agricultural runoff, and improper waste dumping.