Gases are characterized by their lack of fixed form or capacity. Unlike solids, which maintain a consistent structure, and liquids, which hold a specific volume but adapt to their container’s form, a gaseous substance expands to occupy all available space. For example, when a small amount of helium is released into a large, empty balloon, it will distribute itself evenly throughout the balloon’s interior, filling the entire volume.
This fundamental property of gases is crucial in various scientific and industrial applications. Understanding how they behave allows for precise calculations in fields such as meteorology, where atmospheric conditions are predicted, and in engineering, where the design of internal combustion engines and other systems relies on controlled expansion and compression. Historically, the study of gaseous behavior has led to the development of key physical laws, like Boyle’s and Charles’s laws, providing a basis for understanding matter at a molecular level.