It is now set at But instead of setting 0 arbitrarily at the freezing point of water, the Kelvin scale sets 0 at the coldest point possible for matter. The kelvin has been the preferred scale for scientists since , when the General Conference on Weights and Measures CGPM — an international organization that makes decisions about measurement standards — adopted the kelvin K as the base unit for thermodynamic temperature.
The CGPM set a reference point of Since then, the CGPM has set several other reference points to improve thermometer calibration. SI Redefinition. Kelvin: History. Share Facebook. Patient breathing into Santorio's thermoscope. Credit: University of Kansas Medical Center. Metrology and Metric. His interest in French mathematical and scientific methods then inspired him to travel to Paris, where he gained experience in the experimental side of physics by working in the laboratory of Henri-Victor Regnault.
When in the University of Glasgow needed to fill its chair of natural philosophy, Thomson received the appointment with the help of his father, despite being just 22 years old. He returned to Scotland from France and was content to remain associated with the University of Glasgow throughout his career, though he received offers from other academic institutes. While still a student at Cambridge, Thomson embarked on a comparative study of the distribution of electrostatic force and the distribution of heat through a solid that led him to conclude that the two are mathematically equivalent.
This work, published as "On the uniform motion of heat in homogeneous solid bodies, and its connection with the mathematical theory of electricity," was the foundation of his later work involving electric and magnetic fields. Faraday had many years before experimented with light and magnetism, but without observing any connection between the two.
By mid-September he had proven that magnetism and light are related, discovering what has come to be known as the Faraday effect. Similar to Faraday, Thomson seems to have been guided by the idea that there is unity among all types of matter and energy. Collaboration was clearly very important to Thomson, who had made many important connections in the scientific world when he was young through his father and even more when he was older due to his own initiative.
Apply market research to generate audience insights. Measure content performance. Develop and improve products. List of Partners vendors. Share Flipboard Email. Mary Bellis. Inventions Expert. Mary Bellis covered inventions and inventors for ThoughtCo for 18 years. She is known for her independent films and documentaries, including one about Alexander Graham Bell. Updated February 21, Featured Video.
Until recently, scientists thought that humans could not recreate this temperature because to become that cold, energy would have to be added to the system to cool it, meaning that the system would be warmer than absolute zero. But in , German physicists managed to push particles into paradoxical temperatures below absolute zero. To Kelvin's mind, absolute zero was where a temperature scale should begin, but for convenience, he used the markers and intervals of the widely-known Celsius scale as a base for his own.
As such, in the Kelvin scale, water freezes at A single kelvin is referred to as a unit, rather than a degree, and is equal to a single degree on the Celsius scale. The Kelvin scale is mainly used by scientists. In , the Kelvin was redefined to make it more accurate, according to a paper in the journal Metrologia , and its definition is now tethered to the Boltzmann constant.
This constant links temperature to the kinetic energy inside matter. The new definition, according to the General Conference on Weights and Measures , is: "The kelvin, symbol K, is the SI unit of thermodynamic temperature; its magnitude is set by fixing the numerical value of the Boltzmann constant to be equal to exactly 1.
J K-1 [joules per kelvin]. The best scale for measuring temperatures can vary depending on the circumstance, namely the community with whom you are sharing information. Historically, Americans use the Fahrenheit scale for daily life, including for weather and cooking, so it is best to use Fahrenheit measurements in the United States. But most countries use Celsius, so it is better to use that scale across the rest of the globe, and while communicating internationally. Ultimately, the best scale for casual use depends on convention and what people around you are using.
Rather, the precision of a measurement depends on the increments given by the thermometer being used, and the technique of the person using it.
But only the kelvin is physics-based, which means it is the most accurate scale.
0コメント