What causes the droplets of water to form on the outside of the can?

The droplets of water on the outside of a can form due to condensation. When a cold can is exposed to warm, humid air, the temperature of the can lowers the air temperature immediately surrounding it, causing the moisture in the air to cool and condense into tiny water droplets. This process occurs because cooler air can hold less moisture than warm air, leading to the formation of visible water on the surface of the can.