Serial dilution is a laboratory technique used to create a series of solutions with decreasing concentrations of a substance. This process involves taking a known volume of a concentrated solution and mixing it with a specific volume of a diluent, such as water. The resulting mixture is then further diluted in the same manner, often multiple times, to achieve a range of concentrations. This method is commonly used in fields like microbiology and biochemistry to study the effects of different concentrations on microorganisms or chemical reactions. By systematically reducing the concentration, researchers can determine the minimum effective dose or the concentration at which a reaction occurs.