Health

Pain relief: When to use cold, when to use heat

(HealthDay)—Sore from a workout? You don't have to reach for pain relief medicine when ice or heat will help. But when should you go cold and when should you go warm?

Health

A cool-season comfort food without lots of calories

(HealthDay)—If you've been relegating parsnips to the stock pot (their sweetness enhances both chicken and vegetable broth) or have been skipping over them altogether, you're missing out on a hearty side-dish choice for ...

Health

Stock up on these fall superfoods

(HealthDay)—Butternut squash, Brussels sprouts and apples are all amazing fall superfoods and the perfect reason to get cooking.

Health

Get cooking with elegant, flavorful scallops

(HealthDay)—Do you love restaurant-style scallops but feel nervous about making them at home? Here's the 101 to cooking the perfect scallop every time.

Health

Health care workers unprepared for magnitude of climate change

An epidemic of chronic kidney disease that has killed tens of thousands of agricultural workers worldwide, is just one of many ailments poised to strike as a result of climate change, according to researchers at the University ...

page 1 from 23

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.

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