A pocket cooling device based on a cascade mechanism

Recent technological advances have enabled the development of increasingly compact and flexible devices. This includes wearable or portable technology, such as smart watches, earphones or other smart accessories, which can ...

Energy & Green Tech

Solar power stations in space could be the answer to our energy needs

It sounds like science fiction: giant solar power stations floating in space that beam down enormous amounts of energy to Earth. And for a long time, the concept—first developed by the Russian scientist, Konstantin Tsiolkovsky, ...

Electronics & Semiconductors

More skin-like: An electronic skin that can feel

What if we didn't have skin? We would have no sense of touch, no detection of coldness or pain, leaving us unable to respond to most situations. The skin is not just a protective shell for organs, but rather a signaling system ...

Energy & Green Tech

Turning up the heat on molten salt valves

Sandia National Laboratories is partnering with Flowserve Corp. and Kairos Power LLC on a $2.5 million, three-year Department of Energy Advanced Valve Project grant to lower the cost and boost the efficiency of concentrating ...


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.

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