Porosity typically relates to how dense or porous something is and when used to describe hair often relates to the ability of your hair to retain moisture. For most of us porosity is genetic, but it can also be impacted by things we do every day—like processing or chemically treating our hair. Knowing your hair's porosity can help you choose the right products to keep your hair well-moisturized, supple, strong and shiny. You can determine whether your hair has high porosity or low porosity by simply placing a few strands in a bowl of water. If the strands float to the to the bottom that means you have high hair porosity. If your hair still floats at the top after four minutes, it means you have low hair porosity. Read on to see whether you have high hair porosity or low hair porosity.