The main idea that I would like you to get from this set of notes is that convection currents are a swirling motion of a fluid that needs a heat source and a cold source to work. The rest of the notes will deal with supporting this idea and giving some examples of convections currents here on earth.

Once the earth collects enough material it will start to get so heavy that it compresses inward toward the center of gravity a lot. This smashing of the atoms of rock causes them to get really hot. Radioactive atoms are also giving of energy. The combination of the two heat sources made the earth so hot that it turned into a molten ball of rock. The fact that everything turned into a liquid allowed the heaviest material to sink to the center of the earth. This forces lighter material out of the way, eventually placing it on the outside edge of the earth and heaviest material on the inside of the earth. The fact that these layers have been created is actually what allows convection currents to form in the first place.

The layers cause specific material, radioactive material, to be concentrated in the center of the earth. This is important because a concentrated heat source is needed to get convection currents to work. If the heat were spread out all over the place, there would be no place for the heated magma to go. When the core gives off the heat energy from radioactive decay and compression, it excites the electrons of the magma nearby. The atoms of magma will push away from each other as the electrons jump to new energy levels. This makes the magma near the core much more spread out and lighter than the rest of the magma around it. Gravity pulls on the denser magma harder than the lighter magma. So the denser goes down towards the core and forces the lighter magma out of the way so that it goes up towards the surface of the earth. However, if the earth were not layered there wouldn't be a...

...on the bottom of the tank, and the more dense, warm water moves to the top.
The movement of warm and cold water inside the bottles (or tank) is referred to as the convectioncurrent. In our daily life, warm currents can occur in oceans, like the warm Gulf Stream moving up north along the American Eastern Seaboard. Convectioncurrents in the atmosphere are responsible for the formation of thunderstorms as the warm and cold...

...3rd Year Thermodynamics Lab Report
Mechanical Engineering Science 10
Forced Convection (in a cross flow heat exchanger)
Summary
The aim of this lab is to determine the average convective heat transfer coefficient for forced convection of a fluid (air) past a copper tube, which is used as a heat transfer model.
Introduction
The general definition for convection may be summarized to this definition "energy transfer...

...Forced Convection Heat Transfer
I. Introduction
This laboratory deals with forced convection, forced convection can be considered as a staple of heat transfer. That is to say that forced convection can be found in almost any heat transfer problem, and thus understanding its importance and how it affects a given problem is one of the more important learning objectives/outcomes of heat transfer.
When dealing with forced...

...1. Objective
The aim of this laboratory experiment is to analyse the rate of heat transfer losses through convection and radiation separately from a cylindrical glass rod suspended in a pressure vessel. The variation of the dimensionless quantities; Nusselt number, Prandtl number and Grashof Number, with Pressure are to be analysed graphically as well. The experimental graph of log10(Nu) vs log10(Gr.Pr) should be plotted and analysed against the graph of the empirical...

...Experiment 8 - Free & Forced ConvectionConvection Heat Transfer.doc
EXPERIMENT ON FREE AND FORCED CONVECTION HEAT TRANSFER 8.1 OBJECTIVES To study experimental data for heat transfer in order to evaluate the overall heat transfer coefficients and heat balances for the following cases of heat transfer in a .shell and tube heat exchanger. (a) Natural convection and (b) Forced convection. 8.2 THEORY A basic diagram of a...

...4
External Forced Convection
4.1 Introduction to Laminar Boundary Layers 4.1.1 Introduction
Chapters 1 through 3 consider conduction heat transfer in a stationary medium. Energy transport within the material of interest occurs entirely by conduction and is governed by Fourier’s law. Convection is considered only as a boundary condition for the relatively simple ordinary or partial differential equations that govern conduction problems....

...RESEARCH
JULY 2003
Impact of Mixed Convection on Ceiling Radiant Cooling Panel Capacity
Jae-Weon Jeong
Student Member ASHRAE
Stanley A. Mumma, Ph.D., P.E.
Fellow ASHRAE
The main thrust of the research described in this paper was to develop a simplified method of accurately estimating the impact of mixed convection on the cooling capacity of a ceiling radiant panel in mechanically ventilated spaces. The simplified correlation for mixed...

...FREESTUDY
HEAT TRANSFER
TUTORIAL 2
CONVECTION AND RADIATION
This is the second tutorial in the series on basic heat transfer theory plus some elements of advanced
theory. The tutorials are designed to bring the student to a level where he or she can solve problems
ranging from basic level to dealing with practical heat exchangers.
On completion of this tutorial the student should be able to do the following.
•
•
Explain the use of the surface heat transfer...

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