2011-07-01 19:40:06
Interview with Marco Evangelisti and Agustín Camón, senior scientists of the CSIC at the Institute of Materials Science of Aragón.
In these summer times, at least here in Spain, a refrigerator becomes an essential battle companion in the fight against the heat. Of course, when you look at it carefully, heat and cold are rather ambiguous notions that our own body does not know how to interpret very well. As a test, do the following experiment: put one hand in hot water and the other in cold water for a few seconds, then immerse both in warm water. Even though the temperature of the water is the same, one hand will tell you that it is cold and another that it is hot. Our senses deceive us.
Since our senses are not very reliable, we have invented a concept that aims to be objective: temperature. Thermometers are tools that tell us with numbers how hot or cold a body is, but that number tells us nothing about the intimate essence of heat. In microscopic terms, heat is the degree of agitation of the atoms of a body. In theory we can shake an atom as much as we want, without there being an upper limit, which is why we talk about very high temperatures, millions of degrees. However, downwards, towards increasingly colder temperatures, there is a limit. It is located at 273.15 degrees Celsius below zero Why is that number so strange? We invite you to read the answer in the text that accompanies the biography of Heinke Kammerlingh Onnes. One way of counting temperatures consists of placing the “zero” precisely there, which is why we speak of “absolute zero” and the scale is given the name of its inventor: Kelvin. Thus, 0º Kelvin is equivalent to -273.15 ºC.
Since the discovery of absolute zero, scientists have strived to get as close to it as possible. They have not achieved it but they have come very close, just a few millionths of a degree above it. And it was when approaching those temperatures that Nature surprised us with some surprising, wonderful properties, we can say: Materials conduct electricity without resistance, liquids make perfect fluids, certain materials reject magnetic fields and levitate. This is how terms such as: superconductivity, superfluidity or magnetic levitation were born, terms that Ulysses has already explained to us.
The desire to reach temperatures close to absolute zero requires the development of different materials that allow us to approach the goal in an increasingly easier and cheaper way. Today we speak with two people who represent the team of scientists that has developed a new material, gadolinium acetate tetrahydrate, which in some applications promises to become a cheaper alternative to the expensive Helium-3 used until now. The properties of the new material have been presented in a scientific article published in the journal Applied Chemistry Internationalwhose first signatory is Marco Evangelisti, together with him, Agustín Camón, Rosa Lencero and Angel Rodríguez Lozano participated in the gathering.
OTHER RELATED PROGRAMS
Superfluidity and superconductivity. The magic of Science.
Heinke Kammerlingh Onnes, the cold explorer.
REFERENCES:
Institute of Materials Science of Aragon
Marco Evangelisti, Olivier Roubeau, Elias Palacios, Agustín Camón, Thomas N. Hooper, Euan K.Brechin, nd Juan J. Alonso. Cryogenic Magnetocaloric Effect in a Ferromagnetic Molecular Dimer. Angewandte Chemie International‐Edition, DOI:10.1002/anie.201102640
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