Gas

Gas is one of the four fundamental states of matter, alongside solids, liquids, and plasmas. In this state, particles are widely spaced and move freely, which allows gases to expand and fill their containers completely. Common examples include air, oxygen, and carbon dioxide. Gases have no fixed shape or volume, and their behavior is influenced by temperature and pressure. When heated, gas molecules move faster and spread apart, increasing pressure if confined. Understanding gases is essential in various fields, including chemistry, physics, and engineering, as they play crucial roles in processes like combustion and respiration.