In simple words, heat can be explained by the working of molecules and the energy emitted by them creates heat or the emitted energy is converted into heat.
For example, when a person does exercise or any other activity, their body gets heated up and sweat is produced. Or during cooking when food gets warm or heated, it is simply the transfer of heat, through conduction or convection.
The reason behind the transfer of heat is scientific, it might seem easy and cliche to warm food but it has scientific reasons behind it.
The process of transfer of heat can be direct or indirect, there are several materials as well in which heat can be transferred and in some, it cannot be transferred for example not all types of plastic cannot handle the heat.
Key Takeaways
Conduction vs. Convection:
- Conduction is the transfer of heat through direct contact between materials, whereas convection involves the movement of heat through fluids (liquids and gases).
- In conduction, heat moves through a solid without the material itself moving; in convection, heated fluid moves and carries thermal energy.
- Conduction
Conduction vs Convection
The difference between conduction and convection is that in conduction heat is transferred directly whereas convection heat is transferred through the fluid. Both of them lead to the emission of heat but there are differences in method.
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Comparison Table
| Parameters of Comparison | Conduction | Convection |
|---|---|---|
| Definition | Transfer of heat between two objects through direct contact. | Transfer of heat within the fluid. |
| State of matter | Solid | Liquid or gas |
| Transfer of electric current | Allows | Does not allow |
| Density of particles | High density | Low density |
| Rate of transfer of heat | Slow | Faster |
What is Conduction?
Conduction is the process of transfer of heat or current. Conduction is the transfer of energy in the form of heat and current from one atom to another through direct contact.
The best transfer can occur in the solid-state because the atoms are tightly packed which enables the faster rate of transfer of, the density of molecules affects the rate of transfer of heat, on contrary liquid and gases are less efficient in the transfer of heat due to low density of molecules.
There are two types of conduction, those are conduction of heat and conduction of electricity.
Conduction of heat- when the temperature is increased in molecules a vibration is produced and this causes heat in molecules and then the transfer of heat is caused within the tightly packed molecules.
Conduction of electricity- it happens due to the movement of charged particles through any medium. This movement of charged particles causes a current which is carried by ions or charged electrons.
There are several factors which affect the conduction, those factors are; the difference in temperature, length, cross-sectional area, and the material.
The conduction can be calculated through formula in theory by several methods for example by Ohm’s law or by Fourier’s law.
What is Convection?
Convection is the process of transfer of heat through the bulk movement of molecules in any fluid. The initial transfer of heat between the object and fluid takes place due to conduction but afterwards, the bulk movement in particles of fluid creates convection.
The process of convection involves thermal expansion that is when a fluid is heated from below the surface the lower layer of liquid gets heated which gets thermally expanded the density of the molecule is more as compared to the liquid on the upper surface.
There are two types of convection, those are; natural convection and forced convection.
Natural convection- Type of convection in which difference in temperature causes a difference in densities, that is where buoyant force plays a major role. for example, oceanic winds.
Forced convection- a type of convection in which External forces induce convection for example fans, Water heaters, geyser, etc..
Factors that affect convection are; medium ( liquid or gas), temperature, a source which causes heat. One of the differences between conduction and convection is that convection does not support electric current.
Natural convection cannot be calculated easily but the forced Convection can be calculated theoretically through formula given by Newton’s law of cooling. The formula is:-
| P =dQ /dt =hA(T−T0) |
- P= dQ /dt- the rate at which heat is transferred
- h – convection heat-transfer coefficient
- A – exposed surface area
- T – the temperature of the immersed object
- T0 – the temperature of the fluid which is under convection
Main Differences Between Conduction and Convection
- The heat transfer in conduction is slow on the other hand the heat transfer in convection is fast.
- Conduction supports electric conduction as well but convection does not support electricity.
- https://www.sciencedirect.com/science/article/pii/S0375960106013247
- https://www.sciencedirect.com/science/article/pii/S0017931009000271
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Piyush Yadav has spent the past 25 years working as a physicist in the local community. He is a physicist passionate about making science more accessible to our readers. He holds a BSc in Natural Sciences and Post Graduate Diploma in Environmental Science. You can read more about him on his bio page.
