Bunny is a ten year old boy. His motherm Mrs. Bhatia, is having high fever today. Bunny is to go for playing a cricket match with his friends in the afternoon but his white cricket dress is very dirty. He does not know how to operate the washing machine. So, Bunny decided to wash his dirty clothes himself with hands without disturbing his mother. After washing his clothes with detergent powder, he squeezed them well to remove the maximum water out of these clothes. Bunny then kept the washed and squeezed clothers as such in the bathroom ifself for drying. He checked the wet clothes periodically. Bunny found that the wet washed clothes had not dried even after keeping for four hours in the bathroom. Just then Bunny's elder sister Anushka, who is a student of class IX, returned from school. Bunny shared his problem with her. Anushka found that Bunny had kept the washed clothes after squeezing out water as such without even spreading them. Anushka took these wet, washed clothes to the roof of their house where there was still bright sunshine. Even wind was blowing faster on the roof top. Anushka spread the wet clothes properly on the clothes line fixed on the roof of their house. Bunny was glad to find that the wet clothes had now dried in less than two hours.
(a) Which process is involved in the drying of wet clothes ? Define this process
(b) Apart from drying clothes, state another important use of the above process
(c) Why did Anushka spread the wet clothes properly on the clothes line ?
(d) Why did Anushka put the wet clothes in sunshine ?
(e) How did blowing of wind help in the quick drying of wet clothes ?
(f) What values are displyed by Anushka in this episode ?

Explanation

(a) (i) The wet clothes dry due to the evaporation of water present in them. So, the process involved in the drying of wet clothes is 'evaporation'
(ii) The process of a liquid changing into vapour (or gas) even below its boiling point is called evaporation.
(b) The process of evaporation is used to obtain common salt from sea-water
(c) The rate of evaporation increases on increasing the surface area of the liquid (here water). Anuska spread the rapid evaporation of water present in them (which leads to quicker drying)
(d) The rate of evaporation increases on increasing the temperature of liquid (here water). Anushka put the washed wet clothes in sunshine to raise their temperature for the rapid evaporation of water from them (which leads to quicker drying)
(e) The rate of evaporation of a liquid (here water) increases with increasing wind speed. The blowing wind carries away the particles of water vapour from near the wet clothes decreasing the amount of water vapour in their surroundings. This increases the rate of evaporation of water from wet clothes (which leads to quicker drying)
(f) The various values displyed by Anushka in this episode are (i) Awareness of the process of evaporation (ii) Knowledge of the factors affecting evaporation (like surface area, temperature adn wind speed), (iii) Application of knowledge in solving day to day problems, and (iv) Helping nature.