A physical property is a characteristic of a substance that can be observed or measured without changing its chemical composition. Examples of physical properties include color, odor, melting point, boiling point, density, and state of matter (solid, liquid, gas). These properties help identify and differentiate materials. Physical properties can be categorized as extensive or intensive. Extensive properties, like mass and volume, depend on the amount of substance present, while intensive properties, such as density and boiling point, remain constant regardless of the quantity. Understanding physical properties is essential in fields like chemistry and materials science.