MASK FOGGING 😕

Mask fog can be one of the most annoying problems in diving. Warm water vapor in the air comes in contact with the cool mask lens surface and condenses, forming microscopic water droplets. How these water droplets form inside a mask depends on the surface tension on the lens, the humidity of the air inside the mask, and the temperature of the surrounding water.

Also, microscopic depressions on the mask lens surface resemble a golf ball, or the surface of the moon, when magnified under a microscope. Moisture is attracted to this uneven surface and adheres, causing fogging similar to what we experience on a car windshield on a cold day. Decreasing the surface tension of these water droplets and creating a moisture film prevents fogging.

The use of a surfactant like commercial anti-fog, a homemade de-fogger solution (baby shampoo in water) or even spit reduces the surface tension, smoothing out the droplets on the lens. With surfactant applied, condensation is less visible, since the droplets create a more uniform moisture layer. This layer is easier to see through than the “fog” effect of microscopic water droplets.