First, let's get the big words out of the way. Porosity is derived from the word 'pores' and is a measure of how easily fluid can pass through a material. High porosity hair has many pores through which water can pass. Humidity is a measure of the number of dispersed moisture droplets in the atmosphere. On very hot days, such as during the summer season, tiny droplets of water are often suspended in the air in the process of evaporation. Lest I bore you with the chemistry of the water cycle and hair structure, what has moisture in the atmosphere