Class 7 Geography Chapter 5 Question Answers - Water

Short Q & A:

Q1: What would happen if we do not have easy access to water for a long period of time?

Ans: We would not be able to cook food, clean utensils, bath, wash cloth, clean floor, toilet works, brushing, and most important drinking.

Q2: List all the activities for which you need water in a day.

Ans: We need water for so many activities like cook food, clean utensils, bath, wash cloth, clean floor, toilet works, brushing, and most important drinking.

Q3: List some more use of water, apart from our daily activities in which water is required.

Ans: We obtain food from plants, plants needs water to grow and cook their food by the process of photosynthesis. Water is used in industries for processing large number of things that we uses like fabrics, paper etc.

Q4: From where do we get water?

Ans: We get water from water bodies like river, spring, pond, well and hand pump. Although the rain water is the natural source of water that fulfill various water bodies.

Q5: Why water in oceans and seas are unfit for drinking?

Ans: Water in ocean and seas are salty because,many salts are dissolved in it, so it is unfit for drinking.

Q6: Draw a labelled diagram of water cycle.

Ans:

Q7: Why water spilled on a floor dries up after sometime?

Ans: Water spilled on floor dries up after sometimes because of the process of evapouration.

Q8: Why evaporation takes place from all open surfaces of water?

Ans: Evaporation takes place in presence of sunlight, that heats up the open water surface and convert it into water vapour.

Q9: What is transpiration?

Ans: The process of loss of water from the aerial part of plants like leaves is called transpiration.

Q10:  How are clouds formed?

Ans: The water vapours present in sky are gas and cannot be seen. When air is cooled , each water vapour gather with neighbouring water vapour. Thus vapor forms many water drops, each of which consists of many water molecules. One drop is very small and can float in the air. It cannot be seen but when very large number of drops gathers they are visible like fog or smoke. This is called cloud.

Q11:  Why rain clouds are dark in colour?

Ans: Rain cloud is dark because their water drops are larger and less transparent

Q12: What is dew and how it is formed?

Ans: On a clear day, water evaporates from the warm ground into the atmosphere. When night falls, the ground radiates the day's warmth into the skies. The ground becomes much cooler, causing the water vapour to condense. This condensed vapour is dew.

Q13: What happens to the water that rain and snow bring to different regions of earth?

Ans: Some of the water flows in the form of rivers and streams, the rain water also fills up the lakes and pond, a part of rain water gets absorbed by the ground and seems to disappear in the soil. Some of this water is brought back to the air by the process of evaporation and transpiration.

Q14: What is ground water?

Ans: Ground water is the water located beneath the earth's surface in soil and in the fractures of rock formations.

Q15: What happens if it rains heavily?

Ans: Excess of rainfall leads to many problems. It raises the water level in rivers, lakes and ponds. The water may then spread over larger area causing the situation of floods. The crop fields, forests, villages and cities may get submerged by water.

Q16: What happens if it does not rain for a longer period of time?

Ans: If it does not rain for a longer period of time then the water level in rivers, lakes and ponds will go down, some of them may even dry up. The ground water also becomes scarce. This may lead to draught.

Q17: Suggest some methods to conserve water.

Ans: By making wise and judicious use of available water, we can save water. We should not waste water and try to harvest rain water.

Q18: How can we harvest rain water?

Ans: Roof top rain water harvesting- in this system rain water is collected from roof top to a storage tank through pipes. There is one more method in which rain water is allowed to go into the ground directly from the road side drains that collect rain water.

Q19: When does a draught occur?

Ans: If it does not rain for a longer period of time then the water level in rivers, lakes and ponds will go down, some of them may even dry up. The ground water also becomes scarce. This may lead to draught.

Q20: To clean their spectacles, people often breathe out on glasses to make them wet, explain why the glasses becomes wet.

Ans: The most air coming out from mouth condenses on glasses to make glasses wet.

Q21: A cooled bottle of water kept outside refrigerator, shows puddle of water around it. Explain why?

Ans: The cool surface of cooled bottle cools the air around it and the water vapours of the air condenses on the surface of the bottle

Long Q & A:

Q1: The process of condensation plays an important role in bringing water back to the surface of earth. Explain how?

Ans: The Water Cycle is the journey of water from the land to the sky and back again. There are six important processes that make up the water cycle.

1. Condensation - the opposite of evaporation. Condensation occurs when a gas is changed into a liquid.
2. Infiltration - Infiltration is an important process where rain water soaks into the ground, through the soil and underlying rock layers.
3. Runoff - Much of the water that returns to Earth as precipitation runs off the surface of the land, and flows down hill into streams, rivers, ponds and lakes.
4. Evaporation - the process where a liquid, in this case water, changes from its liquid state to a gaseous state.
5. Precipitation - When the temperature and atmospheric pressure are right, the small droplets of water in clouds form larger droplets and precipitation occurs. The raindrops fall to Earth.
6. Transpiration - As plants absorb water from the soil, the water moves from the roots through the stems to the leaves. Once the water reaches the leaves, some of it evaporates from the leaves, adding to the amount of water vapour in the air. This process of evaporation through plant leaves is called transpiration.