Question

Write the differences between evaporation and boiling. 

(OR) 

Sita observed decrease in quantity of spirit kept in a vessel placed in open air. Whereas Ramu observed formation of bubbles on a water surface when it is heated. What are those two processes? Distinguish between those two processes.

Answer 1

Evaporation	Boiling
1. The process of escaping of molecules from the surface of a liquid at any temperature is called evaporation.	1. The process in which the liquid phase changes to gaseous phase at constant temperature. This temperature is called boiling point of liquid.
2. Evaporation takes place at any temperature.	2. Boiling takes place at a definite temperature.
3. The temperature of liquid gets down.	3. The temperature of liquids increases up to a constant temperature.
4. The kinetic energy does not change.	4. The kinetic energy of the molecules increases with the increase of temperature.
5. The evaporation depends on surface area, wind, speed, humidity.	5. The boiling depends on atmospheric pressure.
6. It is surface phenomenon.	6. It is bulk phenomenon.
7. Eg : 1) Wet clothes dries. 2) Sea water evaporates to form clouds.	7. Eg : 1) Water boils at 100° C.