关于“Mpemba Effect”实验的研究

从做"Mpemba Effect"实验入手,对实验现象进行观察,并从物理学及混沌学等方面对其进行了详尽的研究分析,说明此现象即热水比冷水结冰快现象产生的原因及条件,并进一步阐述液体分子间的自组织系统、液体内部组成和液体外部空气的对流及液体的蒸发等对此实验结果的影响程度。

Direct observation of the Mpemba effect with water:Probe the mysterious heat transfer

The Mpemba effect is one of the most perplexing puzzles in nature.Although it has been discussed extensively,direct observation of the Mpemba effect is extremely challenging and rare.Herein,we report the first systematic study of the Mpemba effect with water and clearly point out the conditions required for the observation of the Mpemba effect.The results demonstrate that hot water usually has a faster cooling rate than cold water.The initial temperature,temperature difference,shape of the container,and water volume influence the heat exchange and the cooling process.Owing to the influential factors of heat exchange,the Mpemba effect can only be observed under specific conditions.This work helps to clarify doubts and confusion about the Mpemba effect and can offer alternative strategies for energy storage and transfer materials.

水的姆潘巴效应

相同质量的热水和冷水被放置在同一冷却环境下,热水比冷水结冰快的现象被称为姆潘巴效应.笔者认为水的上表面温度相对较高,即"热顶效应",是发生姆潘巴现象的重要原因,而水的高度越小则越容易形成热顶.文章通过实验表明,水的水位高度较小更容易发生姆潘巴现象.

从“姆潘巴效应”说物理逻辑思维

热水比冷水先结冰的所谓"姆潘巴效应",作为一个物理问题,由牛顿冷却定律进行逻辑分析得出了否定的结果。同样对阿基米德原理,自由落体问题等进行纯逻辑的分析,非常直接地得出了必然的结论,并且可以帮助我们更好地理解物理规律。

A Study of Water Supercooling

The objective of this paper is to investigate water supercooling. Supercooling occurs when a liquid does not freeze although its temperature is below its freezing point. In general, supercooling is an unstable condition and occurs under special conditions. The parameters that influence supercooling stability and probability of occurrence include freezer temperature and water’s initial temperature. In this paper, it is shown that with a freezer temperature range of -3℃ to -8℃, supercooling is most likely to happen and is independent of the water’s initial temperature. Furthermore, as the freezer temperature decreases, the probability of nucleation increases, causing instant freezing. Finally, it is concluded that the Mpemba effect, in which initially hot water freezes faster than initially cold water, is due to the supercooling instability in initially hot water in which nucleation agents are more active.

利用“姆潘巴效应”改进氢键教学

教学设计要重视实验探究的作用,以问题驱动课堂教学,从原有知识和现有知识的认知冲突中,策划高质量的学习活动。基于“姆潘巴效应”分子理论说,以“热水与冷水谁先结冰”为探究主题,以验证“姆潘巴效应”实验为主线,引导学生从分子水平的角度分析“姆潘巴效应”。通过将氢键理论贯穿到整个教学过程中,丰富氢键教学实践,让学生体验科学探究的过程,从而搭建宏观物质与微观世界的桥梁。

姆潘巴现象在速冻米面熟制品速冻过程的应用

在米面制品速冻的过程中,应用姆潘巴现象不仅能减少速冻过程的时间投入,还能降低速冻过程的干耗率。在速冻过程中应用姆潘巴现象还能有效缩短速冻制品通过冰晶生成带的时间。以50、80 g包子为例,分别比较了经过预冷和不经过预冷的包子在速冻时的中心温度变化的差异和产生干耗的不同,从而研究姆潘巴现象与实际生产中的预冷工序存在的这一对矛盾。预冷不仅增加产品的速冻时间和干耗率,同时延长了最大冰晶生成带的时间,这恰好是姆潘巴现象可以解决的。