7.3. DEFINITION OF COMPRESSIBILITY (压缩性定义 All real substances are compressible to some greater or lesser extend d. When you squeeze or press on them, their density will change. This is particularly true of gase (所有的真实物质都是可压缩的,当我们压挤 它们时,它们的密度会发生变化对于气体尤 其是这样7.3. DEFINITION OF COMPRESSIBILITY (压缩性定义) All real substances are compressible to some greater or lesser extend. When you squeeze or press on them, their density will change. This is particularly true of gases. (所有的真实物质都是可压缩的,当我们压挤 它们时,它们的密度会发生变化,对于气体尤 其是这样.)