What is Cell?

Cell is the basic structural and functional unit of life. The word 'cell' was first coined by British scientist Robert Hook in the year 1665. The smallest cell is Mycoplasma gallisepticum. The longest cell is Neuron. The biggest cell is egg of Ostrich.

Schilden and Schwan established cell theory in the year 1838-39. Features of the cell theory :
(i) All organism are composed of cell
(ii) Body of every organism is made of cell
(iii) Each cell arises from pre-existing cell
(iv) Every organism starts its life from single cell

Cell

Evaporation

Evaporation : The process of conversion of a liquid into its vapours at room temperature is called evaporation. Evaporation causes cooling.

Actually, during evaporation, the molecules having higher kinetic energy escape from the surface of the liquid. Therefore cooling takes place during evaporation because of temperature of liquid is directly proportional to average kinetic energy.

Evaporation

Evaporation is affected by following factors :

(i)   Nature of liquid

(ii)  Temperature

(iii) Surface area