What characteristics of water is contributing to the dome of water created in the head of a penny?

The dome of water on the head of a penny is primarily due to water's high surface tension, which is a result of cohesive forces between water molecules. These molecules are attracted to each other, creating a "skin" effect that allows the water to hold a shape rather than spilling over. Additionally, the adhesive forces between water and the penny's surface help maintain the dome's shape by pulling the water molecules upward.