pH Strips in chemistry use a numeric scale used to specify the acidity or basicity(alkalinity) of an aqueous solution. It is roughly the negative of the logarithm to base 10 of the concentration, measured in units of moles per liter, of hydrogen ions. More precisely it is the negative of the logarithm to base 10 of the activity of the hydrogen ion. Solutions that contain a pH less than 7 are acidic, and solutions that provide a pH greater than 7 are categorized as basic. Pure water is neutral, being that it's neither an acid nor a base. Contrary to popular belief, the pH value can be less than 0 or greater than 14 for unyielding acids and bases respectively. pH strips are used to take this measurement. pH capacities are essential in agronomy, nutrition, biology, chemistry, medicine, agriculture, food science, environmental science, oceanography, forestry, civil engineering, chemical engineering, water purification and water treatment, as well as a variety of other applications.