The mass of a specific volume of water is determined by its density. At standard temperature and pressure (STP), water has a density of approximately 1 kilogram per liter (kg/L). Therefore, two liters of water would have a mass of approximately two kilograms.
Understanding the relationship between volume and mass of water is fundamental in numerous scientific disciplines, engineering applications, and everyday life. From calculating the weight of liquids for shipping and handling to determining the water content in biological systems, this basic principle plays a critical role. Historically, the metric system was designed with this relationship in mind, simplifying calculations and facilitating standardized measurements across various fields. This simple yet powerful concept underpins many essential processes, including fluid dynamics, meteorology, and even cooking.