Heat Concept In Physics

Heat or heat energy Heat is the transfer of energy between different bodies or different areas of the same body that are at different temperatures.

Summary

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  • 1 Features
  • 2 Introduction
  • 3 Transfer or transmission
  • 4 Measurement
  • 5 Uses of heat for life
  • 6 Causes and effects
  • 7 Studios
  • 8 Sources
  • 9 External links
  • 10 Related Links

characteristics

This flow always occurs from the highest temperature body to the lowest temperature body, with heat transfer occurring until both bodies are in thermal equilibrium. Energy can be transferred by different mechanisms, including radiation , conduction and convection , although in most real processes they are all present to a greater or lesser degree.

The energy that a body can exchange with its environment depends on the type of transformation that is carried out on that body and therefore depends on the path. The bodies have no heat, but internal energy. Heat is part of this internal energy (heat energy) transferred from one system to another, which happens with the condition that they are at different temperatures. Energy exists in various forms. In this case we focus on heat, which is the form of energy that can be transferred from one system to another as a result of the temperature difference.

Introduction

The existence of life on earth is conditioned by the emergence of energy and heat as a form of it; The Universe is made of matter and energy. Matter is made up of atoms and molecules (which are groups of atoms) and energy causes atoms and molecules to be in constant motion – rotating around themselves, vibrating or colliding with each other. The movement of atoms and molecules creates a form of energy called heat or thermal energy, which is present in all kinds of matter. Even in the coldest voids of space there is matter that has heat, very small but measurable.

Transfer or transmission

Heat transfer always occurs from the hottest to the coldest body. It can occur through three mechanisms: conduction, convection and radiation.

  • Conduction: The process by which heat is transmitted from one point to another of a solid.

Thermal energy is transmitted in conduction, but not matter. Atoms at the heated end begin to move faster and collide with neighboring atoms, transmitting heat energy. The substances have different thermal conductivity, with thermal conductive and thermal insulating materials. Thermal conductors: They are those substances that quickly transmit thermal energy from one point to another. For example, metals. Thermal insulators: They are those substances that slowly transmit thermal energy from one point to another. Examples: Glass , ice , red brick, wood , cork, etc. They are usually porous or fibrous materials that contain air inside.

  • Convection: Convection is the process by which thermal energy is transferred from one point to another of a fluid (liquid or gas) by the movement of the fluid itself.

When heating, for example, water in a container, the bottom part heats up earlier, it becomes less dense and rises, lowering the water from the cooler surface and thus a cyclical process is generated. In convection thermal energy is transmitted through the transport of matter. The existence of other energy transformations that generate heat has been studied.

  • The electromagnetic energy (light of the Sun) heats the Earth . This is the first source of all the energy that reaches Earth and is then transformed into other types of energy.
  • Bodies: emit heat energy in the form of radiation in the infrared.
  • The chemical reactions: combustion give off heat (exothermic), others absorb it (endothermic).
  • Electricity: circulating through a resistance heats it.
  • A ball: when it hits the ground, it transforms its mechanical energy into heat when it deforms.
  • In the human body and that of warm-blooded animals, they transform the chemical energy of food into heat: to live we need 2,100,000 calories a day.
  • Nuclear reactions: generate heat when the mass disappears.
  • By making a sound : we vibrate the air particles and this energy is transmitted in the air: the waves carry energy.

Measurement

  • Measurement. Temperature is the measure of the thermal energy of a substance. It is measured with a thermometer. The most widely used scales to measure this magnitude are the Celsius Scale (or centigrade) and the Kelvin Scale. 1ºC is the same as 1 K, the only difference is that 0 on the Kelvin scale is at – 273 ºC.

On the Celsius scale, the value 0 (0 ºC) is assigned to the freezing temperature of water and the value 100 (100 ºC) to the boiling temperature of water. The interval between these two temperatures is divided into 100 equal parts, each of which corresponds to 1 degree. On the Kelvin scale, 0 was assigned to that temperature at which the particles do not move (lowest possible temperature). This temperature is equivalent to -273 ºC on the Celsius scale. To convert both temperatures, we have to take into account that: T (K) = t (ºC) + 273

  • Use of thermometer and calorimeter. It is necessary to start measuring from a smaller scale at room temperature, and establish one or more measurements to obtain correct data. In humans, the temperature due to fever or colds is measured, which gives the sensation of heat release.

Uses of heat for life

Living beings transform food into energy and, in its view, this energy is a source of heat that warms their blood. Plants receive sunlight that allow the process called photosynthesis (Energy is Life), if there were no heat sources you could not live, that is, we would die from freezing although there are species of the animal kingdom that survive under freezing. With technological advances, the desire for profit, the accumulation of some countries and certain natural processes, a noticeable warming of the terrestrial globe is observed, that is, heat indicators above the tolerable, in some regions more than others, causing perceptible changes in the climate .

Causes and effects

The heat is generated by the collision of the atoms of the molecules which releases certain energy which can be measured. Heat is measured in units of energy. Therefore, in the International System its unit is July (J). However, the traditional unit for measuring heat is the calorie (cal). The equivalence is: 1 cal = 4.184 J or 1 J = 0.24 cal. Evaluating heat in this way demonstrates your ability to do a job. The negative point of heat is its effect on exceeding the limit values ​​for the development of life on the planet, in the absence of heat it is difficult to live and in excess cataclysmic climatic changes are generated. An example of this is the greenhouse effect by altering the protective layers that are part of the Earth’s atmosphere.

Studies

The most advanced studies on energy and heat are based on Nuclear Physics, quantum mechanics , Inorganic Chemistry and Biochemistry and other areas of knowledge, highlighting the studies of Newton, Joul Lemz. Benjamin Thomson – Earl Rumford , JP Joule, Albert Einstein and others.

 

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