Matter exists in different states, primarily classified as solid, liquid, and gas. In a solid, particles are closely packed together and vibrate in place, giving it a definite shape and volume. Liquids have particles that are still close but can move past one another, allowing them to take the shape of their container while maintaining a fixed volume. Gases consist of particles that are far apart and move freely, filling the entire space available. Additionally, there are other states of matter, such as plasma, which occurs at high temperatures when atoms lose electrons, and Bose-Einstein condensates, formed at extremely low temperatures, where particles behave as a single quantum entity.