Fill up the blanks in the following:
a. The process of changing of water into its vapor is called _____.
b. The process of changing water vapor into water is called ____.
c. No rainfall for a year or more may lead to ____ in that region.
d. Excessive rains may cause ____.
a. evaporation,
b. condensation,
c. drought,
d. flood.
State for each of the following whether it is due to evaporation or condensation:
a. Water drops appear on the outer surface of a glass containing cold water.
b. Steam rising from wet clothes while they are ironed.
c. Fog appearing on a cold winter morning.
d. Blackboard dries up after wiping it.
e. Steam rising from a hot girdle when water is sprinkled on it.
a. Appearance of water drops on the outer surface of a glass containing cold water is due to condensation.
b. Stem rising from wet clothes while they are ironed is due to evaporation.
c. Appearance of fog on a cold winter morning is due to condensation,
d. Blackboard dries up after wiping it is due to evaporation.
e. Steam rising from a hot girdle when water is sprinkled on it is due to evaporation.
Which of the following statements are “true”?
a. Water vapor is present in air only during the monsoon.
b. Water evaporates into air from oceans, rivers and lakes but not from the soil.
c. The process of water changing into its vapour, is called evaporation.
d. The evaporation of water takes place only in sunlight.
e. Water vapor condenses to form tiny droplets of water in the upper layers of air where it is cooler.
a. False, Water vapor is always present in air in small proportion.
b. False, Water evaporates into air from oceans, rivers, lakes and also from the soil.
c. True. Evaporation is the process by which water changes into vapour.
d. False. The evaporation of water takes place in sunlight as well as wind.
e. True. Water vapour condenses to form tiny droplets of water in the upper layers of air where it is cooler.
Suppose you want to dry your school uniform quickly. Would spreading it near an anghiti or heater help? If yes, how?
Yes, spreading the school uniform near an anghiti or heater will help to dry school uniform because heat from anghiti causes the rapid evaporation of water from clothes. So, the uniform is dried up quickly.
Take out a cooled bottle of water from refrigerator and keep it on a table. After some time, you notice a puddle of water around it. Why?
When water bottle is taken out of refrigerator, the surface of the bottle is cold which cools the surrounding air and the water vapour in the air condenses around the surface of the bottle. The condensation forms puddle of water around bottle.
To clean their spectacles, people often breath out on glasses to make them wet. Explain why the glasses become wet.
The breath coming out of the mouth is moist and condenses on the spectacle glasses to make them wet.
How are clouds formed?
Clouds are formed when warm and moist air rises, as water evaporates from the surface of the earth and goes higher, it gets cooler. At higher altitudes, the air becomes cool enough that water vapour present in it condenses to form tiny droplets. These tiny droplets keep floating in air form the basis of the cloud.
When does a drought occur?
Drought occurs when it does not rain for one or two years.
Explanation: Due to evaporation and transpiration, the soils, lakes, ponds and wells keep losing water and since it is not brought back by rain, the level of water goes down and some may even dry up. This leads to drought.