Matter is anything that has mass and occupies space. It is the physical substance that makes up all objects in the universe, from the smallest particles to the largest celestial bodies. Matter exists in various states, including solids, liquids, and gases, each with distinct properties and behaviors. The study of matter is fundamental to the field of Physics, as it helps us understand the composition and interactions of everything around us. Matter can also undergo changes, such as phase transitions, where it shifts from one state to another, like ice melting into water or water evaporating into vapor.