Solutions are utilized to some degree in almost all biological research applications. Therefore understanding how to measure and manipulate them is imperative to any experiment. In this video, concepts in preparing solutions are introduced. Solutions consist of a solute dissolved in solvent to yield a homogeneous mixture of molecular substances. Solutions are generally identified by their components and corresponding concentrations. Concentrated solutions are diluted through various methods, such as serial dilution. This video also lays a foundation for the accurate preparation of solutions. For example, the video reviews how to measure volumes with precision through use of the appropriate volumetric container as well as how to read the volume when a meniscus is present. Some applications for measuring volumes are then presented. Gel electrophoresis is a commonly used laboratory procedure which requires preparation of a percent weight volume solution as well as parallel dilution of a concentrated stock solution. Use of a serial dilution to prepare standards for generating a standard curve in protein quantitation is also demonstrated.