Question

why do dogs pant during hot summer days using the concept of evaporation

Answer 1

Dogs do not have sweat glands like us human beings. So the only way for them to lose heat and remain cool in the summer is by panting. When they pant, their saliva evaporates from their tongue and takes a lot of heat with it as water has a high specific heat capacity. Again this is replaced by new saliva from their mouth and the same cycle is repeated.