Visualizing Vapor Pressure: A Mechanical Demonstration of Liquid–Vapor Phase Equilibrium
Visualizing Vapor Pressure: A Mechanical Demonstration of Liquid–Vapor Phase Equilibrium
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可视化蒸气压：液-气相平衡的机械演示
DOI：
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发表时间：
2016
期刊：
影响因子：
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通讯作者：
R. Shaw
中科院分区：
文献类型：
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作者：
D. Lamb;R. Shaw
摘要水相变对于气候和天气至关重要。然而，普遍的经验是，相平衡原理很难理解和教授。我们开发了一个简单的机械类比来证明液体蒸发的关键原理和平衡蒸气压的温度依赖性。该系统由一个中央凹陷的圆形板和数百个金属球组成。板的机械搅拌导致球弹跳并以与真实液-气系统中的分子几乎相同的统计方式相互作用。这些数据由在不同的强迫能量下逃离中心井的球的数量组成，表现出对所施加的能量（类似于热能 kBT）的倒数的对数依赖性，这类似于玻尔兹曼统计和克劳修斯-克拉佩龙方程给出的数据。这些结果表明，蒸发的焓（即潜热）可以很好地解释为势能......
AbstractWater phase transitions are central to climate and weather. Yet it is a common experience that the principles of phase equilibrium are challenging to understand and teach. A simple mechanical analogy has been developed to demonstrate key principles of liquid evaporation and the temperature dependence of equilibrium vapor pressure. The system is composed of a circular plate with a central depression and several hundred metal balls. Mechanical agitation of the plate causes the balls to bounce and interact in much the same statistical way that molecules do in real liquid–vapor systems. The data, consisting of the number of balls escaping the central well at different forcing energies, exhibit a logarithmic dependence on the reciprocal of the applied energy (analogous to thermal energy kBT) that is similar to that given by Boltzmann statistics and the Clausius–Clapeyron equation. These results demonstrate that the enthalpy (i.e., latent heat) of evaporation is well interpreted as the potential energy ...