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Is it true that convection is the flow of heat energy by direct contact?
Wiki User
∙ 7y ago
Convection needs a fluid. More specifically, convection is the motion of a fluid that is caused by the effects of non-uniform density. In all real examples of convection, the non-uniform density is caused by non-uniform temperature.
If you accept the relationship between temperature and density as a given physical law, then you do not need to talk about molecules in order to explain convection; but if you want also to explain why the density changes with temperature, then you probably will need to talk about the molecular nature of the fluid.
Wiki User
∙ 14y ago
Wiki User
∙ 10y agoSimple Answer:
Heat transfer by convection requires a fluid, heat source and gravity. In a fluid, the molecules are "in contact" if it is a liquid and "have collisions" if it is a gas, but the process of convective heat transfer is different than conduction of heat.
Natural heat transfer by convection requires there to be a heat source causing nonuniform temperature in the fluid so that buoyancy of the warmer fluid causes it to rise. Convective heat transfer is the physical movement of material along with the internal energy (or heat energy or thermal energy if you want to call it that) it contains.
Explanation:
When we say heat is transferred by convection, we mean the thermal energy (heat) is actually carried by the material to distinguish from heat conduction through a material.
Convection requires the presence of matter that can move, e.g. liquid or gases exhibit convective heat flow but solids do not.
Normally, convection is driven by buoyancy, so one also needs to have the liquid (or gas) change density with temperature.
Aside: Convection is why we say "heat rises." And, an interesting side observation is that when water cools near the freezing point, it actually gets lighter as the temperature drops from 4 C to 0 C, hence causing the cooler water in that range to be less dense and more buoyant.
Aside: There is also something called forced convection where fluid is moved by artificial means such as air pushed by a fan. Most home heating occurs with "forced convection" but years ago natural convection resulting from bouyancy of hat air was the cause for air circulation.
Wiki User
∙ 13y agoConvection like conduction involves atoms and molecules. This is in contrast to radiation in which heat energy is transferred through photons (light particles).
Wiki User
∙ 7y agoYes, that is true.
BATOUL ALKHATTAB
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When Flow of heat by direct contact is known as?
False... The flow of heat through direct contact is conduction.
The flow that transfers heat within a fluid?
Convection
How does heat flow in solids and fluids?
Either by conduction or convection?
The transfer of heat between two objects touching is called?
When a cold object and a hot object are in direct contact (touching) heat will be transferred through thermal conduction. Normally, heat transfer processes are categorized as thermal conduction, radiative transfer or convection. Heat transfer through thermal conduction is the direct transfer of kinetic energy from one molecule to the nearby molecules. Because temperature is directly proportional to kinetic energy, interactions between neighboring particles exchange energy and that exchange energy gradually works it way from the higher temperature regions to the lower temperature regions. The process of the temperature becoming the same is called thermal equilibration. Convective heat transfer occurs in fluids. If a gas, liquid, or other fluid, changes in fluid density change the buoyancy and will cause fluid to flow (a process called convection) and the heat contained in the warmer fluid is transferred to a new location by the physical movement of the fluid. Radiative transfer occurs when a hot object radiates electromagnetic energy. While the sun is an obvious source of electromagnetic energy, it is also generated in smaller amounts by any object. The hotter objects radiate more electromagnetic energy and the cooler objects absorb it. This radiative transfer is important but not as noticeable usually as the other two. It does occur between objects whether they are in direct contact or not, but is usually so small as not to be important of the objects are touching.
What is an example of energy flow?
Tide = Flow of kinetic energy from higher ground to lower ground Wind = Flow of kinetic energy from higher pressure to lower pressure Electricity = Flow of electrical energy (transfer of kinetic energy) from higher voltage to ground or low voltage.
Is the flow of heat energy by direct contact between molcules?
No.
What is the difference between conduction and convection?
Conduction transfers heat by direct contact. Convection, is the transfer of heat by movement of the medium, due to difference of density caused by changes in temperature.
Is the flow of heat energy by direct contact between molecules?
conduction
How does energy transfer to another object?
By contact (conduction), by gas or liquid fluid flow (convection), by wave (radiation).
When Flow of heat by direct contact is known as?
False... The flow of heat through direct contact is conduction.
What is convection and conduction and what is the difference?
Convection is heat flow by means of moving matter. It only works in fluids (i.e. liquids and gases). Conduction is heat flow by means of direct physical contact. Radiation is heat flow by means of electromagnetic waves. It can work through a vacuum. Heat always naturally flows from something "hot" to something "cold". This is a form of entropy.
What is the flow of thermal energy through a liquid or gas?
Some three types of heat transfers are convection, radiation and conduction.
What h is a way of transferring energy when things are different temperatures?
In that case, energy will flow quite naturally, as a heat flow. Heat can flow through three methods: conduction, convection, radiation.
What happens to particles during the process of convection?
The particles move around from one place to another through the flow of thermal energy during convection.
Is it true or false that energy is transferred to the surface of the sun by the processes of radiation and conduction?
It's false because the transfer of energy through matter by direct contact of its particles is conduction.Have a nice day :)
What is the difference between convection and convection currents?
Convection is the mode of heat transfer, referring to the transfer of heat energy due to bulk motion of a fluid."Convection current" is the name of that bulk motion of the fluid, the transfer of MASS. I prefer to call it buoyantly driven flow. It doesn't flow due to convection, convection is due to if flowing. It flows due to buoyancy in the case of free convection.Peyton
Is convection current kinetic energy before transferring?
In a convection current the kinetic energy will most likely be a small part of the total as the rate of flow won't be very high. Most heat transfer in convection will be simply thermal energy transfer, ie from a warmer place to a cooler one.
