物质的三态
The three states of matter are solid, liquid, and gas.
物质的三态是固态、液态和气态。
熔点
The temperature at which a solid turns into a liquid.
固体变成液体的温度。
沸点
The temperature at which a liquid turns into a gas.
液体变成气体的温度。
粒子理论
A model that explains the behavior of particles in different states of matter.
解释不同物质状态下粒子行为的模型。
密度
The amount of mass per unit volume of a substance.
物质单位体积的质量。