Podcasts about erasto mpemba

Congela prima l’acqua fredda o l’acqua calda? Se facciamo questa domanda è chiaro che ci sarà un trabocchetto. E infatti c’è. Lo diceva Aristotele, lo ripeteva uno scozzese ma il nostro uomo, oggi, si chiama Erasto Mpemba. Un uomo che ha dedicato la sua intera vita a cercare come sia possibile che l’acqua calda, se messa in freezer, congeli prima di quella fredda. Ci sarà riuscito? Scopriamolo insieme.See omnystudio.com/listener for privacy information.

Researchers from Trinity College Dublin have just described the existence of the paradoxical Mpemba effect within quantum systems. Initially investigating out of pure curiosity, the discovery has bridged the gap between Aristotle's observations two millennia ago and modern-day understanding, and opened the door to a whole host of "cool" - and "cooling" - implications. The Mpemba effect is best known as a perplexing phenomenon, where hot water freezes faster than cold water. Observations of the counter-intuitive effect date back to Aristotle who, over 2,000 years ago, noted that the Greeks of Pontus were exploiting the effect in their fishing practices. The Mpemba effect has also stoked the curiosity of other great minds throughout history, such as René Descartes and Francis Bacon. It continues to be the subject of numerous broadsheet articles and pops up regularly as a curious focus in various settings, such as in cooking competition MasterChef, where contestants have tried capitalising on the effect to deliver frozen delicacies more quickly than seems possible in dessert challenges. And now, we can say that this strange effect is much more ubiquitous than we previously expected as the Trinity QuSys team, led by Prof. John Goold from the School of Physics, has just published a fascinating research paper in the journal Physical Review Letters. The paper outlines their breakthrough in understanding the effect in the very different - and extremely complex - world of quantum physics. Prof. Goold said: "The 'Mpemba effect' gets its name from Erasto Mpemba who, as a school kid in 1963, was making ice cream in his home economics class in Tanzania. Mpemba did not wait for his hot ice cream mixture to cool before putting it directly in the fridge and was unsurprisingly puzzled to find that it froze before all the colder samples of his classmates. "He pointed this out to his teacher, who ridiculed him for not knowing his physics - Newton's law of cooling, for example, tells us that the rate at which an object cools is proportional to the temperature difference between the object and its surroundings. However, Mpemba convinced a visiting professor - Denis Osoborne from the University of Dar es Salaam - to test what he had seen and the pair published a paper that indeed evidenced the strange effect." While the Mpemba effect is still not wholly understood - its presence is hotly debated at the macroscopic scale - it is much more apparent on the microscopic scale, where physicists use the theory of quantum mechanics to describe nature. The quantum Mpemba effect has recently become a trending topic, but myriad questions hung in the air; for example, how does the quantum effect relate to the original effect? And can we construct a thermodynamic framework to understand the phenomenon better? The QuSys research group's breakthrough answers some of the key questions. Prof. Goold said: "We are experts in the interface between non-equilibrium thermodynamics and quantum theory and, as such, we have the right toolbox to tackle these questions. Our work essentially provides a recipe to generate the Mpemba effect in quantum systems, where a physical transformation that effectively 'heats' the quantum system can be performed. This transformation of the quantum system then paradoxically allows it to relax or 'cool' exponentially faster by exploiting unique features in quantum dynamics." Using the toolkit of non-equilibrium quantum thermodynamics, the team has successfully bridged the gap between Aristotle's observations from two millennia ago and our modern understanding of quantum mechanics. And it now opens the door to many research and applications-related questions. Prof. Goold added: "While we first took this project on out of intellectual curiosity it forced us to ask several fundamental questions about the relationship between the laws of thermodynamics that describe cooling, and the quantum mechanics, which describe reality at the fundamental...

Episode: 2100 The Mpemba Effect: heating water to make it freeze faster.  Today, another look at an old claim.

Sıcak su gerçekten de bazı durumlarda soğuk sudan daha hızlı donabilir. Yüzyıllar önce Aristo, Bacon ve Descartes tarafından gözlemlenen bu durum 1963'te Tanzanya'da yaşayan Erasto Mpemba isimli öğrenci sayesinde bilim dünyasında tekrar tartışma konusu olmuştu. Bu durum, dondurma yapmak için hazırladığı sıcak süt karışımını sınıf arkadaşının hazırladığı daha soğuk karışımla birlikte buzdolabına koyduğunda, sıcak sütün soğuk sütten daha hızlı donduğuna dikkat eden Erasto Mpemba'ya ithafen “Mpemba etkisi” olarak adlandırılıyor.

Let's say you put two containers of water in a freezer. Water in one container is at room temperature, while water in the other container is hot. Which one will freeze first? Many people would understandably assume the cooler water would be the first to freeze -- and that assumption, oddly, would prove to be incorrect. Join the guys as they delve into the story and struggle of young Erasto Mpemba, the student for whom the Mpemba effect is named, exploring his initial experiments all the way to the ongoing controversy over this strange phenomenon. Learn more about your ad-choices at https://news.iheart.com/podcast-advertisers

Erasto Mpemba aus Tansania macht als Schüler eine physikalisch unlogische Entdeckung: Er stellt fest, dass heißes Wasser schneller gefriert als kaltes. Aber kann das überhaupt sein? Taiina Grünzig lernt auf einem Zwischenstopp in Reykjavik Andrew kennen. Die beiden verbringen eine perfekte Nacht zusammen, wie im Film. Nur ohne Happy End.

You Asked, We Answered! Transcript of the podcast You asked, we answered. What is the mpemba effect? Let’s first start out with who and how this discovery was made. Erasto Mpemba is the one who discovered the mpemba effect. Erasto is a Tanzanian high school student, that is famous for the Mpemba effect [3]. Mpemba’s observations confirmed some of history’s most revered thinkers, such as Aristotle, Rene Descartes and Francis Bacon, they all believed that hot water froze faster than cold water [2]. This was all observed through Erasto’s experiment that he discovered the Mpemba effect. Here is how Mpemba discovered this effect. It all started out with an experiment in his classroom. Most of the students in the room would create a mixture of ice cream. And one day a student arrived late to class and saw other students mixtures were already boiling. The students allowed their mixture to cool after it was boiling hot. After it had cooled down, they would all rush to the refrigerator for a space in the fridge. Another classmate arrived late as well and saw Mpemba boiling his milk and the other student quickly made his mixture with milk and sugar and poured it on to an ice tray without boiling it, so he wouldn’t miss his chance to having a spot in the fridge [2]. After Mpemba saw this, he decided to risk ruining the fridge by putting hot milk into it. As they tried to allow the ice cream to form, the went back an hour later to check on their product and found out that Mpemba’s tray of milk had frozen into ice cream, while his classmates mixture was still only a thick liquid, not yet frozen. Since his discovery, he talked to the professor Dr. Osborne from Dar es Salaam University and the professor performed the same experiment with different materials and came up with similar results as Mpemba [2]. It then made it to modern history, known at the Mpemba effect. However, what causes hot water to freeze faster than cold water? Well, evaporation is the strongest candidate to explain the Mpemba effect. As hot water is placed in an open container, the water begins to cool, and the overall mass decreases as some of the water evaporates [3]. Another idea that leads to hot water freezing faster than cold is because of convective heat transfer. When a liquid is heated, it can form convection currents that rapidly bring the hot liquid to the surface, where the heat is lost by evaporation. Professor Osborne noted that this convection will keep the top of the liquid hotter than the bottom, even when the temperature matches an initially cold liquid that doesn’t possess this convection cooling. This results in a faster rate of cooling that could, under the right circumstances, result in Mpemba’s observation [3]. Dissolved gas can also play a part in Mpemba’s effect, hot water can hold less dissolved gas than cold water, and large amounts of gas escape upon boiling. So, the initially warmer water may have less dissolved gas than the initially cooler water. It has been speculated that this changes the properties of the water in some way, perhaps making it easier to develop convection currents (and thus making it easier to cool), or decreasing the amount of heat required to freeze a unit mass of water, or changing the boiling point [1]. Scientist today are still figuring out the Mpemba effect and how it really works, this study of the Mpemba effect is still on going today, thank you for listening. (This audio file was recorded by Jailene Olmedo, undergraduate student at Penn State Brandywine, on April 9, 2016. References are in attached transcript.) https://www.paesta.psu.edu/podcast/what-mpemba-effect-paesta-podcast-series-episode-16

La pregunta de hoy está basada en una historia que tuvo su origen en 1963, en Magamba Secondary School, en la ciudad de Tanga, Tanzania. Allí, algunos alumnos acostumbraban a hacer helados y, para ello, hervían leche, le añadían azúcar y esperaban a que la mezcla se enfriara a temperatura ambiente antes de ponerla en el congelador del frigorífico. Un día, el estudiante de tercer curso Erasto Mpemba, descubrió, por casualidad, que si ponía la leche hirviendo directamente en el congelador, en lugar de esperar a que se enfriara, se congelaba más rápido que la leche fría. Preguntó el por qué a sus profesores, pero no le hicieron caso. Hasta que Denis Osborne, profesor de física en el University College de Dar es Salaam, visitó el colegio y escuchó la pregunta. Osborne realizó los primeros experimentos encaminados a explicar lo que ahora es conocido como “Efecto Mpemba”.