NCERT Solutions For Class 6 Science Chapter – 14
Q1. Fill in the blanks in the following.
- The process of changing of water into its vapour is called _____.
- The process of changing of changing water vapour into water is called _______.
- No rainfall for a year or more may lead to _______ in that region.
- Excessive rains may cause ______.
Solution:-
- Evaporation
- Condensation
Q2. State for each of the following whether it is due to evaporation or condensation.
- Water drops appear on the outer surface of a glass containing cold water.
- Steam rising from wet clothes while they are ironed.
- Fog appearing on a cold winter morning.
- Blackboard dries up after wiping it.
- Steam rising from a hot gridle when water is sprinkle on it.
Answer:-
Q3. Which of the following statements are “ true” ?
- Water vapour is present in air only during the monsoon. ()
- Water evaporates into air form oceans, rivers and lakes but not from the soil. ()
- The process of water changing into its vapour is called evaporation. ()
- The evaporation of water takes place only in sunlight. ()
- Water vapour condenses to form tiny droplets of water in the upper layers air where it is cooler. ()
Answer:-
Only ( c ) and ( e ) are true.
Q4. Suppose you want to dry your school uniform quickly. Would spreading it near an anghiti or heater help ? If yes, how ?
Answer:-
Yes, if we spread our school uniform near an anghiti or heater it will dry quickly as it will provide heat to water and it will convert into vapour. Quickly. Thus it will dry up quickly.
Q5. Take out a cooled bottle of water from the refrigerator and keep it on a table. After some time you notice a puddle of water around it. Why ?
Answer:-
A puddle of water is formed around a cool bottle because the water vapour near the cold bottle cool down and this results in condensation. Condensation is the process of conversion of water vapour to water.
Q6. To clean their spectacles , people often breathe out on glasses to make them wet. Explain why the glasses become wet.
Answer:-
During exhalation , carbon dioxide is released along with water vapour. If one breathes out, the released water vapour collide with the surface of the glass, thereby making it cooler. As a result, the water vapour present in the air surrounding the glass condense and get attached to the glass surface. Consequently the glass become wet.
Q7. How are clouds formed ?
Answer:-
As air moves up in the atmosphere , it cools down at a sufficient height. The air becomes so cool that water vapour present in it condense to form small water droplets which remain suspended in the atmosphere. These suspended water droplets appear as clouds.
Q8. When does drought occur ?
Answer:-
Drought occurs when an area does not receive rainfall for a period of a year or more. Due to this, soil continues to lose water by evaporation and transpiration and becomes dry.