The Fascination with Convection

Heat transference is defined as the method in which heat is travels from one object to another. Heat always moves from hot to cold. During class, we concurred that energy can never be created or destroyed, but only transferred. Though we have been studying this subject for many weeks, practical uses are still something that we do not grasp completely. A very ubiquitous form of heat transference is convection. Convection is heat transfer resulted by the up and down movement of gases and liquids. Convection occurs in the presence of heat, because hot air expands and becomes less dense, thus making it rise. Though this sounds like a simple process, convection is essential for humans and the rest of the planet.

As humans learned more about convection, it helped clarify many mysteries. Convection causes convection currents, because as hot air rises, the cold air descends. This can also happen in water. A convection current in a liquid is called circulation. If water is heated above a flame, the hot water would expand and float to the top, while the cooler and dense water from the surface descends to the bottom. Understanding this enabled humans to understand different things in the environment such as marine animal migration. Some ocean-based animals change their location based on the ocean currents, which is largely affected by the heat from the sun that causes the ocean create many currents through convection.

Also, convection is thought to play an important role in the transfer of energy between the center and surface of the sun. It also is the reason for the movement of magma beneath the surface of the earth. Some other examples of convection are: wind currents, hot air balloons, and the difference of temperature through a multi-storied building. While convection is a simple process, it affects the environment in countless ways. Infatuation

Bibliography:

"Heat Transfer." ChEE & Cooking. Web. 06 Nov. 2011. .

"Heat Transfer." Web. 06 Nov. 2011. .

"Heat Transfer: Conduction, Convection, Radiation." Welcome to Wisc-Online.com. Web. 06 Nov. 2011. .

Bryan, Julia, and Joshua. "How Do Ocean Currents Affect Migration Patterns of Sea Animals? Have Currents Been Changing in Ways That Are Bad for the Animals?"Oswalt Academy. Web. 06 Nov. 2011. .

Scholorly Sources:

"Handbook of Heat Transfer Applications (2nd Edition)." SAO/NASA ADS: ADS Home Page. Web. 06 Nov. 2011. .

De Vahl Davis, G. "Natural Convection of Air in a Square Cavity: A Bench Mark Numerical Solution - De Vahl Davis - 2005 - International Journal for Numerical Methods in Fluids." Wiley Online Library. Web. 06 Nov. 2011. .

Bioluminescence is Buggin'

When one thinks about cold heat, bioluminescence is probably one of the first things that come to their mind. Bioluminescence is defined as the production and emission of light by a living organism as the result of a chemical reaction during which chemical energy is converted to light energy. It is created by a reaction between luciferin and luciferase, which are a protein and an enzyme, and oxygen. Bioluminescence is a form of cold heat because it is almost 100% efficient: converting nearly all of the energy created from the reaction into light instead of heat or sound.

This insect is bioluminescent, because it produces and emits a light for the purpose of mating. If this insect is producing enough heat to nearly burn a human, it can be assumed that it had some type of problem: inefficiency of cells. If the chemical reaction is inefficient, it means that it would not convert as much energy into light and instead release an unusual amount of heat energy. Since it is hot enough to almost burn the skin of a human, it outlines an exothermic reaction, which is also a combusting reaction in this situation. Combustion is a chemical change accompanied by the production of heat and light. In this situation, the insect is not hot enough to fully combust, but if it emitted enough heat, it would.

Bibliography:

"Bioluminescence." Science Daily: News & Articles in Science, Health, Environment & Technology. Web. 30 Oct. 2011..

"Cold Fire in the Sea - Bioluminescence." ReefQuest Centre for Shark Research Home. Web. 30 Oct. 2011. .

"Conversion Efficiency of a PV Cell." Inventors. Web. 31 Oct. 2011. .

"What Is Combustion?" Physics Help and Math Help - Physics Forums. Web. 02 Nov. 2011. .

Sunlight

Heat transfer is a principal of thermal engineering (the heating or cooling of a process) that is specialized in the exchange of thermal energy (heat energy) from one physical system to another. There are many instances where we can see heat transfer. Some of these mechanisms includes heat conduction, convection, thermal radiation, and phase change transfer. In all these cases, energy in the form of heat is being transferred from a warmer object to one that is cooler. Since this energy transfer follows the law of conservation of momentum which says that energy cannot be created nor destroyed, we know that if one object is gaining heat energy, the other object is losing it.

The specific instance I’m using is thermal radiation. As we know from earlier classes and other research we have done, thermal radiation is heat generated by matter because of the charged particles in that matter, object with fast moving particles have more heat. Sunlight is an example of when heat transfer occurs. The electromagnetic waves (energy traveling through space) also known as radiation encounter an object. The waves will then transfer the heat to that object. A specific example of this is when sunlight comes in contact with a house. When the electromagnetic waves come in contact with the house the temperature inside that house goes up. The energy coming from the heat waves is converted in to kinetic energy (the energy something has because of its motion) in the particles of the object it is heating. This is why when you leave something out in the sun for too long, its internal temperature will go up. One way that the heat energy from the sun affects our ecological economy is that plants need heat energy to grow and survive. Though they do not need as much heat energy as light energy, the heat energy is still important to make the enzymes work.

Scholarly articles

Mark Bishop (Lead Author);Tom Lawrence (Topic Editor) "Heat transfer". In: Encyclopedia of Earth. Eds. Cutler J. Cleveland (Washington, D.C.: Environmental Information Coalition, National Council for Science and the Environment). [First published in the Encyclopedia of Earth June 24, 2008; Last revised Date June 24, 2008; Retrieved November 6, 2011 <http://www.eoearth.org/article/Heat_transfer>

Luebbers, Ralph H. "Heat Transfer." Encyclopedia of Earth. ©McGraw-Hill Companies, 2008. Web. 06 Nov. 2011. .

Heat Transfer

Heat transference is the exchange of thermal energy, or heat, between two substances. Anytime an object is heated, it is because of heat transfer since, due to the laws of conservation of energy, energy can neither be created nor destroyed; high concentrations of heat want to move to low concentrations of heat and visa-versa. Therefore, heat transference is what causes everything to heat up or cool down. On a chemical scale, quickly moving and hot molecules interact with slower moving and cooler molecules and transfer some of their energy (which in this case is in the form of heat) to them until the two substances reach equilibrium.

A good every-day example of heat transfer is when a person makes a snowball with bare hands. The person transfers energy to the snow in an effort to achieve equilibrium. The person’s hands will get colder as energy in the form of heat is transferred to the snowball. In contrast, the snowball will begin to melt as it absorbs some of the energy from the person’s hands. This is an excellent example of heat transfer because it occurs very often and is a simple representation of heat transfer.

Scholarly articles:

“The physiological equivalent temperature – a universal index for the biometeorological assessment of the thermal environment” by P. Höppe. International Journal of Biometeorology. May 26, 1999. http://www.springerlink.com/content/pu50qardua56k6em/

“Journal of Fluid Mechanics” by PR Owen and WR Thomson. Journal of Fluid Mechanics. March 28, 2006. http://journals.cambridge.org/action/displayAbstract?fromPage=online&aid=369150

Thermal Radiation as Heat Transference

Heat transference is the process by which heat moves between one substance and another. As we know from our study of the property of ‘q,’ energy is never created nor destroyed; rather it is just transferred through the release or gaining of heat between reactions between substances. radiation is one of the most common forms of heat transference that we encounter in our everyday lives. It is the process by which electromagnetic waves travel through space and when those waves come in contact with an object they emit heat. There are many different kinds of radiation and each has varying levels of harmfulness. Gamma rays for example, can be extremely detrimental to our health if one is overexposed to them, while microwaves have a much lower frequency, and therefore are much less harmful to us.

There are an infinite number of benefits to humans having harnessed the power of thermal radiation. All matter with a temperature greater than zero emits thermal radiation. Without it we wouldn’t be able to create hearths for our homes, have hot water, have light bulbs, use microwaves, having thriving nature, or cook over a stove.  Sunlight is a form of thermal radiation emitted from the sun, obviously. Sunlight is an essential agent in the process of photosynthesis which allows plants to grow and create fruits and vegetation from which we eat. Besides its domestic uses, sunlight also contributes to the sustaining of natural habitats which are essential to our ecosystem for numerous reason among which include contributing to photosynthesis to allow plants to thrive meaning with plants we can receive more oxygen and create habitats for creatures living there. Trees can also be cut down to sustain parts of our economy, to build homes, etc.

But for every benefit that heat transference brings to the environment, there is an equal and opposite negative toll it takes.  One of the most harmful effects of thermal radiation is the fact that by nature, thermal radiation has the capability to ignite matter. And while yes, this can often be a benefit to our environment, in many cases this can create grave danger; for example in dry areas like around Californian forests, these trees are susceptible to their ecological infrastructure igniting and having a forest fire occur. Additionally, heat transference is a contributing factor to Global Warming. Although the atmosphere is for the most part opaque and thermal radiation from Earth's surface is absorbed by the atmosphere, radiation still escapes into space. It is then subsequently absorbed and emitted back by atmosphere gases. This is what evidently contributes to Global Warming.

Bibliography:

1.       Huebsch, Russell. "Thermal Radiation Effects | EHow.com." EHow. Web. 02 Nov. 2011. <http://www.ehow.com/about_5544786_thermal-radiation-effects.html>.

2.       "Solar Radiation and the Earth's Energy Balance." Columbia University | Earth and Environmental Sciences. Web. 02 Nov. 2011. <http://eesc.columbia.edu/courses/ees/climate/lectures/radiation/>.

Scholarly articles:

1.      Höppe, P. "The Physiological Equivalent Temperature – a Universal Index for the Biometeorological Assessment of the Thermal Environment." Springer. International Journal of Biometeorology. Web. 2 Nov. 2011. <http://www.springerlink.com/content/pu50qardua56k6em/>.

2.      Howell, John R., and Robert Siegel. "Thermal Radiation Heat Transfer, Vol. 1." Taylor & Francis Publishing. Web. 02 Nov. 2011. <http://books.google.com/books?hl=en>.

3.      Wong, Nyuk Hien. "Investigation of Thermal Benefits of Rooftop Garden in the Tropical Environment." Science Direct. Elsevier Science Ltd. Web. 02 Nov. 2011. http://www.sciencedirect.com/science/article/pii/S0360132302000665.

Bioluminescence

Bioluminescence is the production and emission of light by a living organism (such as fireflies!) The animals that have bioluminescence contain two chemicals called luciferin, which is a pigment, and luciferase which is an enzyme. When luciferin reacts with oxygen it creates light, and the luciferase acts as a catalyst to speed up the reaction. The chemical reaction within the bug causes the heat that we fill when touching an animal with bioluminescence. For something to combust it must reach a temperature of 175 degrees Celsius. In this case, animals/insects with bioluminescence only reach around 100 degrees Celsius, which will certainly burn skins when contact is made, but will not cause the animal or insect to burst into flame and die. The reason why it does not reach temperatures as high as 175 degrees Celsius is because in order for combustion to occur, oxygen, a fuel, and energy. Within a bug or animal that has bioluminescence, there is not enough oxygen for the species to combust, but enough to produce heat.

Bugs makin' art

Biolumiescence is the emission of energy that is caused by living, ecological things. The most common living creature that is able to emit energy is insects and they do this in the form of light. Insects such as fireflies emit light in the form of bioluminescence. Bioluminescence is the reaction that occurs when the pigment luciferin, oxygen, and the enzyme luciferase come together. Usually the reaction occurs once the luciferin and the oxygen react with each other to produce light either inside of the cell or outside of the cell of the insect. The enzyme, luciferase, like most enzymes, is helpful in speeding up the chemical reaction that occurs between the pigment and the oxygen. This is why the pigment and the oxygen are necessary for insects to glow, without each of these the insect would not have any glowing capability.

Bioluminescent Insects Glowing in the Darkness, Karl Fabricius