Claim: Hot water can freeze faster than cold water

Question

This article discusses the controversy about whether hot water can freeze faster than cold water. It cites experiments that claim to prove that this phenomenon (called the Mpemba Effect) can occur under certain conditions, while also stating that many researchers are not persuaded by the results of these experiments.

Comments

Why did you choose to use a magazine as your source of information? Magazines have been seen to be not a credible source, so how were you sure that you were able to trust the information provided?

---

While it is true that magazines are generally seen as not credible sources, this one in particular does link to legitimate research papers regarding the experiments that are discussed in the article.

https://www.nature.com/articles/s41586-020-2560-x
https://www.pnas.org/doi/10.1073/pnas.1701264114

---

At first glance, I thought this claim was impossible to prove that hot water could freeze faster than cold water and did not want to have any firsthand assumptions until proven otherwise. But after reading multiple articles and watching some videos on this theory i would have to confidentially say that hot water cannot freeze faster than cold water.

My first piece of evidance includes an article with two differnt claims about hot water freezing faster than cold water or if cold water boils faster than hot water in this case were only focused on one subject but this article is provided research evidence as well a specific book / video one can research about the law behind this physics called (Conceptual Physics, by Paul G. Hewitt (HarperCollins, 1993) explaining how this theory cannot be proven unless in the rare case of having luke warm water be the test subject but with your claim of hot boiling water this theory behind the law of physics explained would not be proven likely

my second piece of evidence from this article (https://www.scientificamerican.com/article/is-it-true-that-hot-water/) provides two pieces of research from induvial universities and how they tested this theory and provided evidence that again it would not be impossible with a specific rate of temperatures again being Luke warm water vs boiling water. evidence is based from (Robert Ehrlich of George Mason University, in Fairfax, Va., adds to some of the points made by Takahashi) as well as (Fred W. Decker, a meteorologist at Oregon State University in Corvallis, encourages readers to settle the question for themselves)

and finally i watched a most recent updated video taking a step by step process behind the law of physics whether or not hot water can freeze faster then cold and found out that it cannot a video from 2017 from sciecicum claims to be true with 4.5 million views (https://www.bing.com/videos/riverview/relatedvideo?q=can+hot+water+freeze+faster+then+cold+water&mid=F99CD874544A57838BA8F99CD874544A57838BA8&FORM=VIRE)

Answer 1

In most cases, an identical container of cold water will freeze faster than an identical container of hot water. The hot water will cool at a faster rate than the cold water, but the cold water will reach the freezing point first as it starts much closer. This may create the illusion that hot water is freezing faster, but that is only because the freezer is working harder to bring the temperature down.

There are a few circumstances in which hot water is capable of freezing faster than cold water due to evaporation or supercooling. If the hot water loses volume to evaporation, then it could take less time to freeze than the cold water. Hot water also is less likely than cold water to supercool, which means to freeze at a temp lower than the freezing point. 

Sources: MIT Article, UCR Article

Comments

I really like this response, it was thorough, explained effectively the phenomenon of hot water seemingly cooler faster than cold, and explain misconceptions. The author of your MIT article seems to be a legit journalist that is credible to answer the question as her LinkedIn says she's worked with engineering and such. Good job!

Answer 2

 The very interesting claim that hot water freezes faster than cold water, known as the Mpemba effect, is extremely controversial and not consistency proven. Adam Mann, the writer of this article, doesn't necessarily use sources from another article published recently, but he uses older sources such as Erasto Mpemba himself from his observations from 1960. Since his observations occurred, the phenomenon has been the subject of various studies and mixed results. Other sources Mann used, physicists Henry Burridge and Paul Linden, represented that measurement sensitivity could produce false information for the effect, showing the readers that temperature variations in rapidly cooling water complicates consistent outcomes. Theories like evaporation, which reduces volume, and the presence of dissolved gasses in cold water further attempt to explain this effect.

https://www.pnas.org/doi/10.1073/pnas.1701264114

Now, heading into the recent research, hence the link, we dive into non-equilibrium systems, such as Zhiyue Lu and Oren Raz, explain that under certain conditions, hotter systems might reach lower energy states faster, but this research doesn't convincingly demonstrate the actual idea of water. The scientific community seems to be divided when it comes to this research, while many experts acknowledge the fact that the Mpemba effect lacks universal acceptance due to the complexities of thermodynamic behavior. Sources like Quanta Magazine and the original studies by Mpemba and Osborne provide credible insights into this ongoing debate