Question

why do we get dew on the surface of the cold soft drink bottle when. kept in open air

Answer 1

it's due to loss of temperature.

Answer 2

When we keep a cool soft drink, in the open air, the glass/ bottle's surface will have dew drops.Because, when the molecules of the air come and hit the surface, the kinetic energy of those molecules will be loosed, and will be transfered to the surface, then to the drink.We know that average kinetic energy is directly proportional to the temperature.Thus the temperature of the soft drink increases. We know that when heat or coldness is lost it is transfered to the body which is in contact with it.Thus the coldness is transferred to the water vapour present in air. We know that, when water vapour cools, it forms in to dew drops.Thus dew drops are formed on the surface of bottle consisting of cold soft drink, when kept in open air.