Glossary term: 质量
Description: 质量是一个物体所含物质的总量。构成物体的原子的数量、类型和密度共同决定了物体的质量。在日常用语中，质量和重量这两个概念经常被相互替换，但在物理学中，它们其实并不相同。质量在任何位置都保持不变，而重量则取决于当地的引力场。
质量有两种概念：“引力质量”和“惯性质量”。其中，“惯性质量”是物质抵抗运动状态变化的特性，它即是牛顿第二定律中的质量。我们看到，加速度与质量成反比。因此，在给定力的作用下，质量越大的物体加速度越小。
“引力质量”则是物质产生并受到引力的特性，质量越大的物体所受到的引力越大。
爱因斯坦通过他的“等效原理”断言，引力质量和惯性质量是完全相同的。这是物理学中的一个基本概念。
千克（kg）是国际公认的质量计量单位（也可使用其他单位，如克、毫克、吨、盎司和磅），质量用符号m表示。质量是一个标量，并且是一种形式的能量。因此，质量可以在核反应等过程中转化为其他形式的能量，而且质量并不是严格守恒的。自然界中存在无质量的粒子，如光子——携带电磁辐射的粒子。
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Term and definition status: The original definition of this term in English have been approved by a research astronomer and a teacher The translation of this term and its definition is still awaiting approval
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