Why does dew form on a cold softdrinks?

Question

Why does dew form on a cold softdrinks?

Answer 1

At night the air cools and can hold less moisture than warm air.  As the air is being cooled, the relative humidity will rise from its daytime value (perhaps 70%) until it reaches 100% and any further cooling (below this dewpoint temperature) will cause excess moisture to condense on leaves (etc.) as dew.  If the cold glass of softdrink is below the dewpoint temperature for the moisture level in the house, dew will form on the glass.  Notice that dew forms easily on a hot muggy day during the summer but not often during the winter with relatively dry heated air in the house.

Answer 2

The air can sustain a certain amount of water as a gas. The colder the air, the less it can sustain. As air cools down either by the proximity of your glass, the radiation of heat during the night or the cooling with altitude, the air then reaches its saturation temperature and must condense in water droplets.

But that requires to give away energy in form of heat. Yes it does! Since the water molecules are nearly without a mass, the heat transfer doens't happen until  it meets something.

For your drink, it is the glass.

For the cooling of the night and the morning dew, it is a flower, leave, just anything.

For the clouds to form in the atmosphere, it is just any dust of corn, smoke, etc. Without that, clouds can't form. Without that, water can't either form ice. That's why in the winter dew is frost and when that happens to the wings of an aircraft, the pilot must quickly activate the de-icing systen otherwise the plane will go down in no time. Don't ask me how I know ... I am a private pilot, piloting my little aircraft without de-icing system in Norway!

Answer 3

The chilled drink cools water vapour in the surrounding air causing it to condense on the surface of the drink container.