Why do we get dew on the surface of a cold soft drink bottle kept in open air?

Dew forms on the surface of a cold soft drink bottle due to the process of condensation. Condensation occurs when warm, humid air comes into contact with a cooler surface, causing water vapor in the air to turn into liquid water.

When a cold soft drink bottle is placed in open air, the warm and humid air surrounding the bottle comes into contact with the cooler surface of the bottle. The water vapor in the air then condenses on the cold surface of the bottle, forming tiny droplets of water, which we perceive as dew.

Here's a step-by-step explanation of the process:

1. Warm, Humid Air: The air around us contains water vapor, which is invisible to our eyes. The amount of water vapor in the air depends on factors such as temperature and humidity. When the air is warm and humid, it contains a higher concentration of water vapor.

2. Cold Bottle Surface: When a cold soft drink bottle is placed in open air, the surface of the bottle is at a lower temperature than the surrounding air. This temperature difference creates a temperature gradient, with the bottle surface being the cooler region.

3. Contact and Cooling: The warm and humid air comes into contact with the cold surface of the bottle. As the warm, moist air comes in contact with the cooler bottle surface, it begins to cool down.

4. Condensation: As the warm, humid air cools down, the water vapor in the air condenses into liquid water. This is because cold air holds less water vapor than warm air. As the air cools, it reaches its dew point, which is the temperature at which the air becomes saturated and can no longer hold the water vapor.

5. Droplet Formation: The condensed water vapor forms tiny droplets of liquid water on the cold surface of the bottle. These droplets coalesce and become visible as tiny beads or droplets of dew on the bottle's surface.

The formation of dew on a cold soft drink bottle is a common example of condensation, a fundamental process in nature that is also observed in the formation of clouds and precipitation.