Electronics & Semiconductors

Radiative cooler that cools down even under sunlight

Now that autumn is upon us, there is a large temperature gap between day and night. This is due to the temperature inversion caused by radiative cooling on the Earth's surface. Heat from the sun during the day causes its ...

Energy & Green Tech

Offshore wind research buoys float into California's waters

Two offshore wind research buoys managed by the U.S. Department of Energy's (DOE's) Pacific Northwest National Laboratory (PNNL) were deployed recently off the coast of California. This marks the first time the buoys have ...


Engineers print wearable sensors directly on skin without heat

Wearable sensors are evolving from watches and electrodes to bendable devices that provide far more precise biometric measurements and comfort for users. Now, an international team of researchers has taken the evolution one ...

Electronics & Semiconductors

Smart suit wirelessly powered by a smartphone

Athletes are always on the lookout for new ways to push the limits of human performance and one needs to first pinpoint their current limits objectively if they seek to overcome them. A team of researchers from the National ...

Electronics & Semiconductors

Tandem devices feel the heat

Understanding how solar cell operation changes as it moves from the lab into the real world is essential for optimizing their design prior to mass production. KAUST researchers show how perovskite/silicon tandem solar cells ...


Robot takes contact-free measurements of patients' vital signs

During the current coronavirus pandemic, one of the riskiest parts of a health care worker's job is assessing people who have symptoms of COVID-19. Researchers from MIT and Brigham and Women's Hospital hope to reduce that ...

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In physics, temperature is a physical property of a system that underlies the common notions of hot and cold; something that feels hotter generally has the higher temperature. Temperature is one of the principal parameters of thermodynamics. If no heat flow occurs between two objects, the objects have the same temperature; otherwise heat flows from the hotter object to the colder object. This is the content of the zeroth law of thermodynamics. On the microscopic scale, temperature can be defined as the average energy in each degree of freedom in the particles in a system. Because temperature is a statistical property, a system must contain a few particles for the question as to its temperature to make any sense. For a solid, this energy is found in the vibrations of its atoms about their equilibrium positions. In an ideal monatomic gas, energy is found in the translational motions of the particles; with molecular gases, vibrational and rotational motions also provide thermodynamic degrees of freedom.

Temperature is measured with thermometers that may be calibrated to a variety of temperature scales. In most of the world (except for Belize, Myanmar, Liberia and the United States), the Celsius scale is used for most temperature measuring purposes. The entire scientific world (these countries included) measures temperature using the Celsius scale and thermodynamic temperature using the Kelvin scale, which is just the Celsius scale shifted downwards so that 0 K= −273.15 °C, or absolute zero. Many engineering fields in the U.S., notably high-tech and US federal specifications (civil and military), also use the kelvin and degrees Celsius scales. Other engineering fields in the U.S. also rely upon the Rankine scale (a shifted Fahrenheit scale) when working in thermodynamic-related disciplines such as combustion.

This text uses material from Wikipedia, licensed under CC BY-SA