New water vapor condenser takes cues from darkling beetle

Access to clean water is a huge issue across the globe. Even in areas with water resources, a lack of infrastructure or reliable energy means purifying that water is sometimes extremely difficult.


Modeling shows the true cost of heat on PV system performance

Lowering the operating temperature of solar panels by just a few degrees can dramatically increase the electricity they generate over their lifetime, KAUST researchers have shown. The hotter a panel gets, the lower its solar ...

Energy & Green Tech

Weakness is strength for this low-temperature battery

Nanoengineers at the University of California San Diego have discovered new fundamental insights for developing lithium metal batteries that perform well at ultra-low temperatures; mainly, that the weaker the electrolyte ...

Energy & Green Tech

Experts discuss what went wrong with Texas power grid

On Feb. 13, a severe winter storm swept across Texas and nearby southern states, bringing sub-zero temperatures and snowfall as far south as the border with Mexico. The polar air that descended on Texas lasted many days, ...


Attachable skin monitors that wick the sweat away

A new preparation technique fabricates thin, silicone-based patches that rapidly wick water away from the skin. The technique could reduce the redness and itching caused by wearable biosensors that trap sweat beneath them. ...


Underwater soft robot inspired by the brittle star

Soft robots are better suited to certain situations than traditional robots. When interacting with an environment, humans or other living things, the inherent softness built into the structure of a robot made of rubber, for ...

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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.

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