A physical property is a property that can be observed or measured without altering the identity or composition of a substance. Such properties are central to identifying substances and to physical separations, because they can be examined while the substance remains chemically unchanged. Colour, density, and melting point are physical properties, whereas a substance's tendency to burn is a chemical property.

物理性质是无需改变物质的本质或组成即可观察或测量的性质。这类性质对于鉴别物质和进行物理分离十分重要,因为在物质保持化学不变的情况下即可考察。颜色、密度和熔点都是物理性质,而物质的可燃性则属于化学性质。