Private Pilot Private Exam

What is generally the first element involved in the formation of thicker fogs?

1. Temperature drop

2. Decrease in sunlight

3. Increase in wind speed

4. Increase in air pressure

The correct answer is: Temperature drop

Thicker fogs typically form when there is a drop in temperature, which leads to the air reaching its dew point. As the temperature falls, the air can hold less moisture, and when it becomes saturated, condensation occurs, creating fog. This is especially true when the air cools down overnight or under calm conditions, allowing moisture in the air to condense into tiny water droplets that collectively constitute fog. While factors such as a decrease in sunlight can contribute to a temperature drop, it is the temperature drop itself that directly causes the conditions ripe for fog to form. Increased wind speed would generally disrupt the formation of fog by mixing the air and preventing saturation, and an increase in air pressure does not directly relate to fog formation in this context. Understanding the relationship between temperature and moisture saturation is key to grasping why a temperature drop is fundamental in the formation of thicker fogs.