- published: 05 Jan 2014
- views: 62594
Convection is the concerted, collective movement of groups or aggregates of molecules within fluids (e.g., liquids, gases) and rheids, through advection or through diffusion or as a combination of both of them. Convection of mass cannot take place in solids, since neither bulk current flows nor significant diffusion can take place in solids. Diffusion of heat can take place in solids, but that is called heat conduction. Convection can be demonstrated by placing a heat source (e.g. a Bunsen burner) at the side of a glass full of a liquid, and observing the changes in temperature in the glass caused by the warmer ghost fluid moving into cooler areas.
Convective heat transfer is one of the major types of heat transfer, and convection is also a major mode of mass transfer in fluids. Convective heat and mass transfer take place both by diffusion – the random Brownian motion of individual particles in the fluid – and by advection, in which matter or heat is transported by the larger-scale motion of currents in the fluid. In the context of heat and mass transfer, the term "convection" is used to refer to the sum of advective and diffusive transfer. In common use the term "convection" may refer loosely to heat transfer by convection, as opposed to mass transfer by convection, or the convection process in general. Sometimes "convection" is even used to refer specifically to "free heat convection" (natural heat convection) as opposed to forced heat convection. However, in mechanics the correct use of the word is the general sense, and different types of convection should be qualified for clarity.
A Physics revision video explaining the process of heat transfer by Convection.
A simple demonstration of convection. Come see the rest of my videos at www.anglesandacid.com
Convection appears in many systems in the universe. A heated fluid will expand, increasing the volume, and decreasing the density so the heated fluid floats in its surroundings. When cooled the fluid will sink in its surroundings. This movie highlights 2 demonstrations used in science class. Demo #1 is the Chimney Demo (a.k.a the RED SMOKER) while Demo #2 highlights special convection fluid being heated. We find convection in earth's mantle and believe it drives earth's plates. Ocean currents are driven by convection. Our winds are driven by temperature differences that cause convection and thus air movement. Finally we believe that convection plays a role at the surface of the sun where its evidence is found in the granulation we see. This Video was originally posted 1 year ago ...
Descriptions and pictures. Middle School level.
Convection! Who cares? You should! Discover how heat is transferred in liquids and gases! How convection effects us through wind, earthquakes and its implications in the home! How do sea breezers occur? Ocean currents? How does it heat rooms? It's all explained here, whether you like it or not!
Lecture Series on Heat and Mass Transfer by Prof. S.P.Sukhatme and Prof. U.N.Gaitonde, Department of Mechanical Engineering, IIT Bombay. For more details on NPTEL visit http://nptel.iitm.ac.in
A short video explaining how convection works. This is for GCSE science and applies to various exam boards. Check the website for a complete video list that covers Core (all unit 1s), Additional (all unit 2s) and Separate Science (all unit 3s). www.my-GCSEscience.com
Using a small fish tank filled with water placed over a bowl of hot water and a bowl of ice, the convection currents can be seen using red and blue food dye. A great demo for school science.
In this lecture an introduction is given on the fundamentals of convection. The following is discussed: physical mechanism of convection, forced convection, natural convection, heat transfer coefficient, the velocity boundary layer, no-slip velocity on surface, calculation of heat transfer from the temperature gradient at a surface, Nusselt number, and physical significance of Nusselt number. The lecture was presented as part of a heat transfer class to the fourth year students of the Department of Mechanical and Aeronautical Engineering by Prof Josua Meyer, Head of the Department of Mechanical and Aeronautical Engineering of the University of Pretoria, South Africa. Lecture was presented on 19 March 2014.
A day of death upon the cross of deceit
impure with pleasure to bare witness to he
death calling you to christ, human sacrifice, conviction
down the unseen, your belief, absent god, don't exist
go unto thou, from the dead, walk with him, he ain't there
love in retreat, uncompelled, feel no pain, pray unfelt
hate run in place, holy grace, contemplate, there's no god
the work of jesus was the devil in fact
his miracles were nothing more than a trap
lies pinned upon the cross, crucify his false religion
conviction, choking on the crucifix in his blood
conviction, take the bullet for the love of a son
conviction, from the cross into his kingdom you go
conviction, no more bullshit from the likes of the lord
satanic visions bring the lord to his death
their own disenchantment of perversions confessed
caught, harrow in disgust, revel in your lost religion
conviction, choking on the crucifix in his blood
conviction, take the bullet for the love of a son
conviction, from the cross into his kingdom you go