Related topics: electricity

Thermodynamic magic enables cooling without energy consumption

Physicists at the University of Zurich have developed an amazingly simple device that allows heat to flow temporarily from a cold to a warm object without an external power supply. Intriguingly, the process initially appears ...

Capturing energy flow in a plasma by measuring scattered light

Whether studying the core of our sun or the inside of a fusion reactor, scientists need to determine how energy flows in plasma. Scientists use simulations to calculate the flow. The simulations rely on the classical thermal ...

Solar evaporator offers a fresh route to fresh water

About a billion people around the world lack access to safe drinking water. Desalinating salty water into drinkable water can help to fill this dangerous gap. But traditional desalination systems are far too expensive to ...

Could climate change cause infertility?

The scientific community has long held an understanding about the effect of temperature on sperm production in mammals, but this new study sheds light on how spermatogenesis in insects is hampered at extreme temperatures.

Predicting heat waves? Look half a world away

When heavy rain falls over the Indian Ocean and Southeast Asia and the eastern Pacific Ocean, it is a good indicator that temperatures in central California will reach 100°F in four to 16 days, according to a collaborative ...

Simultaneous heatwaves caused by anthropogenic climate change

Without the climate change caused by human activity, simultaneous heatwaves would not have hit such a large area as they did last summer. This is the conclusion of researchers at ETH Zurich based on observational and model ...

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Heat

In physics and thermodynamics, heat is the process of energy transfer from one body or system to another due to a difference in temperature. In thermodynamics, the quantity TdS is used as a representative measure of the (inexact) heat differential δQ, which is the absolute temperature of an object multiplied by the differential quantity of a system's entropy measured at the boundary of the object.

A related term is thermal energy, loosely defined as the energy of a body that increases with its temperature. Heat is also loosely referred to as thermal energy, although many definitions require this thermal energy to actually be in the process of movement between one body and another to be technically called heat (otherwise, many sources prefer to continue to refer to the static quantity as "thermal energy"). Heat is also known as "Energy".

Energy transfer by heat can occur between objects by radiation, conduction and convection. Temperature is used as a measure of the internal energy or enthalpy, that is the level of elementary motion giving rise to heat transfer. Energy can only be transferred by heat between objects - or areas within an object - with different temperatures (as given by the zeroth law of thermodynamics). This transfer happens spontaneously only in the direction of the colder body (as per the second law of thermodynamics). The transfer of energy by heat from one object to another object with an equal or higher temperature can happen only with the aid of a heat pump, which does work.

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