The heat or thermal energy is transmitted for two reasons:

• existence of a temperature gradient between the bodies;
• change of physical characteristics.

When a body exchanges heat because of temperature differences, it's called dry exchange and the energy transmitted is called sensitive heat, while the heat transfer involving change of state is called wet exchange and the energy transmitted is called latent heat.

Dry heat exchange (heat sensitive) constitutes forms of heat transfer that occur due to a gradient temperature and can occur by conduction, convection or radiation.

Heat transfer by conduction is the transmission of heat molecule to molecule, hence need of a material medium, occurring always from a point of greatest potential energetic (higher temperature) to a lower potential (lower temperature). Thermal conductivity characterizes if the material is a better or worse heat conductor, the thickness and opacity of the material will determine the amount of heat flux.
The flow of heat transported by conduction can be determined by Fourier's law with the following heat transfer equation:

q = k. ∆T ⇒ Q =S.k. ∆T ⇒ E = S.k. ∆T ∆t
L L L
This equation is also represented as follows:
q = ∆T or q = K t . ∆T
R₁
Heat transfer by convection is the transmission of heat that occurs between a solid body and a fluid movement, the body fluid may be liquid or gaseous. Natural convection when the fluid motion occurs only due to variations in its specific weight (density). In forced convection the motion of fluid is caused by a pump, in the case of a liquid, or a fan in the case of a gaseous fluid. It is experimentally verifiable the amount of heat flow in the process of convection is directly proportional to the temperature gradient between the solid material and the region of the fluid not "disturbed " by the displacement of fluid. The physical quantity that characterizes the convective process more or less intense is called the coefficient of heat convection exchanges (hc). This Heat transfer equation enables to establish heat transfer by convection

q = hc.(Tsi - Tar)

Heat transfer by radiation occurs when radiation emitted by bodies being in a certain positive temperature therefore, possessing atomic and molecular motion emit electromagnetic radiation. In electromagnetic theory, the quantities characterizing the radiation are its frequency and its wavelength, as shown in this heat transfer equation:

c = λ . f

The relation between mass and energy, as presented in corpuscular theory is represented by the following heat transfer equation :

E = m.c²

The heat transfer occurring by conduction is affected by the resistance or by the thermal conductance of the construction element, while the heat transfer of the air and neighboring elements is influenced by surface conductance coefficient that encompass the thermal exchanges occurring on the surface of the wall by convection and radiation.

Wet thermal exchange (latent heat) normally occurs when we transfer heat to a body increases its temperature. In terms of construction, the study of wet heat exchange is important on evaporative cooling systems and condensation problems, both superficial and internal. The processes of latent heat exchange is also important in physiological mechanisms of homeothermy maintenance through evaporation in the respiratory tract and sweating, constituting, even in warm climates, the main route of elimination of body heat. The psychrometry is the part of physics that, through a psychrometer, mesures and studies hygrothermal conditions and thermodynamic properties of mixture of atmospheric air with water vapor (humidity).

The heat transfer equation is available in many different forms. There are about four different equations according to the different heat transmitters. The thermal resistance equation, the time required to heat an object, heat loss or gain through a container and heat loss or gain through convection.

The different equations are based on different alphabet which represent different functions. As in the thermal resistance equation of the heat transfer equation is

Where;

L is the length in meters (m)
K is the Thermal Conductivity of the material in watts/meter C
A is the cross sectional area in meters squared (m²).

The measurement of heat in length and what is its thermal conductivity is an important aspect to make sure that area that is being measured is in the right context. Conduction of different experiments related to different chemicals and heat producing equipment should be worked upon carefully so as not get any damage done to your self or your surroundings. Any kind of high ratio in the heat can result in minor or big explosions which have been faced by many scientists as well so all those people who conduct experiments as a hobby or for fun sake should be very careful.

Similarly different letters represent different meanings. The heat transfer equation is usually used in some kind of an experiment specifically in the labs of different schools and universities. People who are related with the field of chemistry or physics often need to conduct such experiments that require the heat transfer equations.

It tells the difference between different containers when they are heated. The equations of the transferring of heat also refer to different laws of science specifically the physics laws of Newton.

People who have interest in science specifically in chemistry and physics know about these equations. They know what importance they have and how they can be used.

If you want to conduct any experiment related to heat and science you should take a look at all the equations to see which is the one that you require for your experiment. It would definitely help you in making your experiment easy to perform. It also lessens the risk that you might encounter if heating any thing more or less during an experiment. If anything additional or in a wrong quantity is added to any kind of experiment it can also end up in making your experiment useless.