Subatomic Particles and The Standard Model

As the name might suggest, subatomic particles are particles that are smaller than an atom... Which is an interesting conundrum for the atom: The Greek root for the word atom, "atomon," means "that which cannot be divided." 
When atoms were first decidedly discovered, they were thought to be fundamental, a not-dividable particle that made up all elements. But as compounds and solutions were broken down into elements, and these elements became more categorical, it seemed that even individual atoms had to possess smaller building blocks.


"...experiments which "looked" into an atom using particle probes indicated that atoms had structure and were not just squishy balls. These experiments helped scientists determine that atoms have a tiny but dense, positive nucleus and a cloud of negative electrons (e^-)."(Berkeley Lab, 2011)

Picture credit: wikispace History of the Atom

Soon enough, scientists had determined that an atom is made up of three sub-atomic particles: Protons and Neutrons in the nucleus and that cloud made up of the much smaller elementary particle, the electrons. But are these three particles fundamental? Well, the electrons are. 


So electrons are (to date considered) fundamental subatomic particles. But what, then, are protons and neutrons made of? 
Protons, it turns out, are made of two "up" quarks and one "down" quark, held together with a "cloud of gluons" (R. Nave).
Neutrons are made up of two "down" quarks and one "up" quark. 


What scientists have developed to determine fundamental particles is the Standard Model Theory. This theory has been supported through experimentation in particle accelerators such as the Large Hadron Collider(LHC) at CERN. 
The Standard Model has 12 fundamental matter particles: six quarks and six leptons. The up and down quarks are just two of the quarks; there are also: charm, strange, top and bottom quarks.
Leptons include the electron as well as the following: neutrino electron, muon, tau, muon-neutrino and tau-neutrino.

picture credit: Cern, http://public.web.cern.ch/public/en/science/standardmodel-en.html

These particles are members of multiple generations, 1st, 2nd and 3rd. Up and down quarks, for example, make up the first generation of quarks. The second and third generation particles are heavy and unstable and quickly decay to the more stable first generation. This is why our protons and neutrons are made of first generation quarks, and why it is electrons that occupy the cloud surrounding the atom's nucleus.


The Standard Model Theory does include forces and carrier particles which play a role in keeping atoms together. Carrier particles are carrying three of the four forces known: strong and weak nuclear forces and electromagnetism. Note that gravity is not included which is part of the reason that this model is not considered complete enough for the science community. These forces hold together the matter particles and the carrier particles include bosons, photons and gluons. Photons carry electromagnetism, bosons carry the weak force and gluons carry the strong force. Now if gravity could be added to the Standard Model, a carrier particle called a graviton could be included, but so far, scientists have not been able to produce any results to add the force and its carrier. This is one of many goals of the LHC and it's collaborators. 












References:
Berkeley Labs. http://particleadventure.org/standard-model.html. accessed 29Dec2011

Nave, C. R. and Sheridan, John, The Microwave and Infrared Spectra and Structure of Hydrothiophosphoryl Difluoride, Journal of Molecular Structure 15, 391, 1973. (http://hyperphysics.phy-astr.gsu.edu/hbase/particles/proton.html).

CERN, European Organization for Nuclear Research http://public.web.cern.ch/public/en/science/standardmodel-en.html . 2008.

Nobel Prize 2011 Physics: Dark Energy and Accelerating Expansion of the Universe

When you throw a ball into the air, gravity will eventually cause it to stop it's upward movement and accelerate it back toward you, right? Well, what if that ball kept going up? For that matter, what if it kept going up and increasing its speed as it did so? 
We would have to assume that something, some force, is working harder then the force of gravity. This is not so hard to believe as far as the forces go...of the four known basic forces (weak and strong nuclear forces, electro-magnetic force and gravity), gravity is observably the weakest. But lets assume the ball is not fitted with a magnet headed toward a massive piece of iron and that we have not fitted it with nuclear reactor boosters...what, then, could be working against the gravity?


This is the conundrum that Nobel Laureates Saul Perlmutter, Brian Schmidt and Adam Reiss faced when they discovered that the universe was expanding...at an accelerated rate. 

For a long time, scientists believed that the universe was static; this was due to a paradox that Newton was aware of after his discovery of the force of gravity. According to his law, Newton realized that if the universe were finite, that it should be collapsing due to stars attracting one another...but that did not appear to be the case and so the universe was determined to be static. 

http://www.popgive.com/2010/06/brain-twisting-paradoxes.html 
Olbers’ paradox is the argument that the darkness of the night sky conflicts with the assumption of an infinite and eternal static universe. It is one of the pieces of evidence for a non-static universe such as the current Big Bang model. 

The problem with this was that a static universe would make an infinite universe and that could not be...if the universe were infinite, our night sky would be as bright as day from all the stars shining from the endless reaches of space (whether the light came from close by or gazillions of light-years away, an infinite universe means stars "forever").
 Newton was aware of the paradox, but decidedly stuck by the static universe theory. Years later, Einstein also realized that according to his theory of General Relativity, the universe should be expanding or collapsing, but to fix that, he came up with the cosmological constant, cancelling the effect of gravity on a large scale, thus keeping a static universe as the rule (SDSS, Expanding Universe). 

Image credit: grandunificationtheory.com 

Edwin Hubble, with the assistance of "larger telescopes...being built that were able to accurately measure the spectra, or the intensity of light as a function of wavelength, of faint objects (SDSS, Expanding Universe)," then discovered the universe was indeed expanding. Through the observations of distant galaxies, Hubble discovered that the redshift of these galaxies increased the further they were from the earth. This led Einstein to call his cosmological constant his "biggest blunder." Now scientists knew that the universe was not only finite, but that because it was expanding, there was a point in time and space where the universe was incredibly small and dense; it had a beginning...a "Big Bang.


Enter Nobel Laureates, Brian Schmidt, Adam Reiss and Saul Perlmutter. From Nobelprize.org's popular information:


 "Saul Perlmutter headed one of the two research teams, the Supernova Cosmology Project, initiated a decade earlier in 1988. Brian Schmidt headed another team of scientists, which towards the end of 1994 launched a competing project, the High-z Supernova Search Team, in which Adam Riess was to play a crucial role."

Using IA supernovae (the death of white dwarf stars in a binary star system, to be specific) as basis for their measurements, the two competing teams came to the same surprising conclusion: Yes the universe is expanding, but it was not slowing down as previously believed. While trying to determine the fate of our universe, the teams had found that the supernovae were becoming much fainter then expected. This find was to be the key to the roles that the mysterious dark energy and dark matter play in the cosmos. Where a vacuum of nothing in space should be, there is something. That something must be working against? or with? gravity to accelerate expansion in a universe that is supposed to be slowing down. Dark energy and dark matter are believed to make up 95% of our universe, while we, the earth, the moon, the sun and all the stars...all other matter...only comprise the last 5%. 


With the discovery of acceleration came the true value of Einstein's cosmological constant. Without the cosmological constant, the formula for expansion would not allow for acceleration. So Einstein's blunder could turn out to be the value of that vacuum of space that contains "something."


So, as a toddler who continues to ask why with each answered question, our universe presents new unknowns with each discovery!







References:
Sloan Digital Sky Survey (SDSS). http://skyserver.sdss.org/dr1/en/astro/universe/universe.asp . viewed on 12/11/2011.

"The Nobel Prize in Physics 2011 - Popular Information". Nobelprize.org. 11 Dec 2011 
http://www.nobelprize.org/nobel_prizes/physics/laureates/2011/popular.html


Perlmutter, S. (2003) Supernovae, Dark Energy and the Accelerating Universe, Physics Today, vol. 56,no.

Galaxies!

This is another guest post from my nine-year-old daughter, Lilian. Lilian loves astronomy and was excited to do this one! -Dorian

By Lilian Satterlee

When you look up at the night sky, you might only see tens of stars in the area of your galaxy. But all you see is not all there is! Our galaxy has not only 50 stars, but billions. We live in a galaxy called the Milky Way, a spiral galaxy with hundreds of thousands of billions of stars.

Our Milky Way Galaxy



IC 1011, largest known galaxy

 As big as it is, it is only a speck compared to this giant: IC 10-11 is the largest galaxy ever found. It is 60 times larger than our Milky Way.
M 87 is one of the oldest galaxies in the known universe.

M87

Our neighbor, Andromeda

Andromeda is our nearest neighbor. All galaxies are different, unique, big and everywhere.


How Galaxies Formed!
It takes gravity to make stars and pull them together. Early galaxies were a big mess; lumpy clumps of stars, dust and gas. Today, galaxies are neat and organized, and gravity is what makes that happen.

So remember, galaxies are made of billions of stars and there are billions of galaxies!

Nobel Prize 2011 Chemistry: Dan Schechtman

This is called a Penrose Tiling. This demonstrates the aperiodic layout of repeated tiling which gives an artistic visual of the quasicrystal.

I was first introduced to quasicrystals in physicist Lisa Randall's book, Warped Passages: Unraveling the Mysteries of the Universe's Hidden Dimensions. Randall was using them as an example of an every day item that may reflect "an ordered structure in a higher-dimensional world." She was talking about the Teflon on a pot or pan. Correction added 15OCT2011: Teflon is not what Ms Randall is describing... "non-stick" surface is more accurate...Teflon products have been around since long before the discovery of the non-stick effects of quasicrystal-reinforced surfaces. I apologize!

Dan Schechtman discovered the "impossible" crystalline structure over 20 years ago in a lab. In April of 1982, Schechtman had rapidly chilled a molten mix of aluminum and manganese expecting to observe complete disorder at the atomic level. Instead, he saw a crystal, except, it was one that did not make any sense.

It is important to note that the paradigm at the time was that crystals existed in limited numbers of rotation symmetry: 1, 2, 3, 4 & 6 fold. Not 5, and not greater then 6.

Quick vocabulary break down:
Crystals - usually, when atoms are arranged in a way which is periodic
Rotation Symmetry - When a shape or image can be rotated and it still looks the same. For 4-fold symmetry, for example, if you rotate the image four times, it looks the same each time (a square is of four fold symmetry).
Paradigm - a constant based not on theory but observation.

How the structure of an atom is observed: shine a monochromatic (or single wave-length of) xrays on a specimen. That beam is diffracted by the atoms and displays a pattern on the other side. This is where the symmetry number is revealed.

This is how an electron microscope works. What Schechtman saw was a diffraction pattern of electrons on a t.v. scanner...

What Schechtman did with his aluminum-manganese mix was observe the diffraction using an electron microscope and that diffraction pattern displayed a crystal with five-fold symmetry. It went against the paradigm which had existed since 1912! He quickly ruled out "twinned" atoms, or atoms which would have a mirror image in symmetry. What was significant about five-fold symmetry was that it produces a pattern that cannot be repeated; it takes the "periodic" out of the crystalline structure.

Schechtman was ridiculed by his peers for years, and he was even kicked out of his research group when he refused to back down on his findings.

Over the years, Schechtman's findings were slowly accepted into the scientific community and applied to modern technology, making stainless steel stronger (especially for small tools and instruments such as electric razors and surgical tools) and surfaces slicker. Quasicrystals have even been found to naturally occur in minerals found in a Russian river.

In her book, Lisa Randall explains the significance of quasicrystals to scientific theories that require extra spacial dimensions: "Quasicrystals are fascinating structures whose underlying order is revealed only with extra dimensions." As in, that periodical structure that can't be found in quasicrystals in three dimensions, may be, while not observable (by us), possible in extra dimensions of space. This would help to understand that non-stick pan coating: "The nonstick frying pans that are coated with quasicrystals exploit the structural differences between the projections of higher-dimensional crystals in the pan's coating and the more mundane structure of ordinary three-dimensional food."



Dan Schechtman's discovery resulted in some fantastic theory support as well as important applications. It is well deserving of a Nobel Prize. Congratulations, Prof. Schechtman!



References:

Randall, Lisa. Warped Passages Unraveling the Mysteries of the Universe's Hidden Dimensions. Harper Perennial. 2005.

"The Nobel Prize in Chemistry 2011 - Popular Information". Nobelprize.org. 10 Oct 2011 http://www.nobelprize.org/nobel_prizes/chemistry/laureates/2011/info.html

Technion Institue - Interview with Prof. Dan Shechtman.
http://www.youtube.com/watch?v=EZRTzOMHQ4s

Just Some Optical Illusions

Well, due to the start of school (for my kid, not me...) this next week and travelling for work, I have been neglecting my poor science blog! :( Have no fear...though I don't have anything of depth prepared, I'd like to take this opportunity to display some things I have stumbled across while surfing the web and for this post, some illusions I had not up to this point encountered yet. I hope you enjoy and I promise to resume my regularly scheduled programming very soon!!

Are these really spiralling? :)

I like this next one, and nope, no animation! :)

And this video is a great compilation of some good illusions...accompanied by some fun music and a silly man, lol. ;)

Thank you all! If you have any good links to illusion pics or videos, please share in the comments!

Oil Spill Series: Waves

Waves

“Although there are many processes and factors that may need to be taken into consideration to assess operational safety or the fate of spilled oil, the dominant process on shorelines is that of wave action (Owens, 1-8).”

There are two aspects of waves I want to expand on here: the origination of waves out at sea, and the behavior of the wave when it reaches the shore.

Origination of Waves

That’s easy enough: Wind. Any questions? Just kidding…Though not about the wind part. Lets travel out to the open ocean.

At first, the wind doesn’t have much to work with…the surface of a calm sea provides little roughage for the wind to push on and create movement. It is the tiny ripples that form as the wind moves over the surface that begin to travel (as oscillating waves) and GROW the more surface the crest gives for the wind to push on…make sense? Let me put it this way:

The second and third pictures here are showing the effect of “wind stress” which is what is happening as the wave allows more surface area for the wind to push…therefore, wind stress is a square function (oh, imagine that with the natural parabola formed in the wave trough! I love when math shows up in nature…) that is conversely dependant on the roughness of the sea, which depends on the wind stress. Clear as mud? Good. Lets move on.

Fetch: The distance which wind blows over water.

This is what is causing fully developed seas to become swell.

Now, in case it hasn’t been made obvious yet, the water is NOT traveling with the wave…the wave is an oscillation of energy traveling through the medium of liquid, in this case the ocean water. In fact, as you travel deeper under the surface of the water (in the deep ocean) that oscillation disappears slowly. This aspect is what changes as you near the shore…where the waves “break.”

Waves, Shallow Water and the Shoreline

As the swell travels toward the shore, it encounters shallow water. Now the energy of the wave actually causes the water in place to travel in a circular motion (this is why it does not travel fully forward with the wave). As the circular motion of the water encounters the sea-bed, it becomes elliptical. This happens when the depth of the water is half the wavelength (Bloomfield, 293).

Now we have a wave that is slowing down due to obstacle (seafloor) and bunching together. In addition to this, the height of the crest and depth of the trough (or its amplitude) increases to keep up momentum despite the slowing. Now, as all this is happening, the wave begins to refract, or bend the direction of travel, to approach the beach or shore more directly.

Now, as the crest of the wave carries forward the circular motion, the bottom encounters the shore or land and this causes the momentum to create the breaking of the wave.

Formulas:

Wind stress magnitude is calculated from wind magnitude as τ = c_a ρ_a |u|²

where ρ_a = 1.2 kg m_-3 is the density of air, c_a = 0.0015 a dimensionless drag coefficient, u the wind speed and |u| its magnitude.

As Pertains to Oil Spills

There are a couple of things to remember about waves during an oil spill response. There exist what are called wave generated beach cycles.

“When waves reach the shoreline, they dissipate their energy:

• Spilling or surging breakers tend to build up a beach (accretion), and
• Plunging breakers move sediments seaward causing erosion (Owens, 1-12).”

This difference in dissipation of energy needs to be recognized so that the responder can know where to look for the oil on a particular beach.

If you are dealing with commonly spilling or surging breakers, you will be looking up the beach and digging, whereas, with plunging breakers, be aware of oil coming ashore more slowly over time.

Reference:

Bloomfield, Louis A. How Things Work. John Wiley & Sons, Inc. 2006.

Owens, Ed. Shoreline Operations and SCAT Surveys for Oil Spills on the West Coast. Polaris Applied Sciences, Inc. 2010

I Interrupt This Series to Bring You Breaking News: Quick Blurb on Hurricanes

How Hurricanes Form

What is needed:

·         Warm water (at least 80° F)

·         High humidity

·         Moist air

·         Warm surface temperatures

This is why hurricanes can be tracked for a while in advance; they typically form off the coast of Africa in the Atlantic ocean, by the equator, and travel over the open ocean. This gives the continuous evaporation and condensation cycle that is necessary to the tropical storm to get stronger. As the water condenses, it gives off latent heat and this decreases surface pressure.

Now the air begins to rotate around the low pressure area, continuing the evaporation and condensation cycle.

Irene in particular is encountering an area of dry air, which will help to weaken her. However, the risk of storm surges (which are usually what cause the most significant damage when a hurricane is due to make landfall) is still high and extremely likely.

Storm Surges

These are exactly what they sound like. Surges of the coastal waters being pushed by the wind and low pressure (this is responsible for about 5% of the surge). With Irene pushing on toward densely populated parts of the North Eastern United States, this is a huge issue regardless of her category being downgraded; between high sea-level populations and underground transit systems, the damage is estimated to be in the multibillion dollar range (Associated Press, 26AUG11).

Oil Spill Series: Tides

The physics of the ocean is essential to understanding the science of an oil spill. Besides the actual content of the oil and its effect on the environment, it is important to understand how the water behaves. This leads to processes which can determine the behavior or weathering of the oil. It plays a role in a responder’s ability to conduct clean-up.

When oil hits the water, earth’s forces immediately begin to go to work on it, both from above and below. For this segment, we look at how the tides work.

Tides

One of the cool things about the tides is that despite the constantly varying heights, they are completely predictable. We have predicted tides for a hundred years and more in the future (when I say “we” I don’t mean me…sounds like a completely tedious task, but I am glad someone out there enjoyed it enough to do it).

The tides are being influenced by three things: Gravity of the moon, the Earth’s rotation, and even a bit by the Sun’s gravitational pull. Each day, as the earth rotates, the gravitational pull of the moon creates a “bulge” on the earth and this causes a tidal change from low to high and high to low every 6 and a half hours.

Twice a month, the sun and moon are aligned (Full Moon and New Moon). When this occurs, the gravitational pull is even stronger and creates what are called Spring Tides. When the moon is at a right angle to the sun (half moon), the tidal change is less significant and is called a Neap Tide. The spring tide during the equinoxes have the highest tidal range (Owens, 1-17).

Equinox: the time when the sun crosses the plane of the earth's equator, making night and day of approximately equal length all over the earth and occurring about March 21 (vernal equinox or  spring equinox) and September 22 (autumnal equinox).

With these parameters laid out for us, the rule of thumb is that the tides at the equator (where the bulge is) are typically larger than those to the north or south. That is, until you take into account the geography.

Where your normal equatorial tide change is typically right around 2 meters, an example of a large tidal change due to tidal resonances is the Bay of Fundy (located between New Brunswick and Nova Scotia). The geography of this estuary supports a 15 meter tidal change (Bloomfield, 288)!

Resonance: is the tendency of a system to oscillate at a greater amplitude at some frequencies than at others

Resonance is a fascinating topic for another post, but note: due to the design of the landscape which the wave is traveling through, this tidal resonance occurs and causes phenomena such as the Bay of Fundy, the Cook Inlet in Alaska, and a handful of others.

Now, keeping in mind that this massive tidal change must still take place within the span of 6.5 hours, you can imagine the speed at which the ocean must move. Don’t get caught out there! This is a good concern to keep in mind when an oil spill response occurs in these areas…

 

The tank vessel EXXON VALDEZ struck Bligh Reef on March 24^th, 1989. What is the significance of this date? Remember the effect that the equinox has on tides and when the equinox occurs? Also, what is the average tidal change for an area like Prince William Sound? These tidal effects all played a part in the behavior of the spill and the direction of the response to it.

 

Reference:

Bloomfield, Louis A. How Things Work. John Wiley & Sons, Inc. 2006.

Owens, Ed. Shoreline Operations and SCAT Surveys for Oil Spills on the West Coast. Polaris Applied Sciences, Inc. 2010

Series: Oil Spills

For the next few posts, I will be talking about subjects that I have become familiar with in my job: Oil Spills. Where they go, what happens to the ecosystem, the science behind response and response equipment, etcetera.

Keep in mind throughout the series that all the elements of oil spills are complex and variable; like fingerprints, no two oil spills are alike, even if they are in the exact same location. As I write and publish each of these posts, I will update this post with links to the posts that are part of the series. As an introduction, here are some pictures:

"This is a radar image of an offshore drilling field about 150 km (93 miles) west of Bombay, India, in the Arabian Sea. The dark streaks are extensive oil slicks surrounding many of the drilling platforms, which appear as bright white spots."

 Source: http://www.jpl.nasa.gov/radar/sircxsar//oilsk.html

The EXXON VALDEZ and the oil spill caused by the vessel's collision with Bligh Reef in1989.

Clean-up during the Exxon Valdez spill...this technique was not always better then leaving the oil in place, which I will address when I post about mechanical clean-up techniques.

This is a sattelite image of the Deepwater Horizon oil spill in the Gulf of Mexico, taken days after the intial oil-rig explosion in April, 2010. This turned into the worst environmental disaster in U.S. history. Photo from The Global Herald

Disclaimer: Any views and/or opinions expressed in The Masqerading Scientist are solely those of the author and not of the U.S. Coast Guard or any other U.S. federal agency. Thank you!

Plan to Save the Whales

This is a guest blog post written and illustrated by my daughter, Lily. She is 9 years old and has a passion for these wonderful creatures. These views are not all necessarily the views of anyone BUT a wonderful and curious little girl, so please, Enjoy!

Plan to Save the Whales

You know, lots of people love whales and they love to see whales; but the whales are endangered. To keep up the fun of whale watching, we need to do something before they are extinct.
Easy Home ways to save the whales:

• Cool down the earth by biking or walking to places that aren't far away
• Turn off electronics when not in use
• When you go to the bathroom, don't use a lot of toilet paper, because everything that goes down the toilet or drain ends up in the ocean
• Take short showers and don't make them that hot.

Whales sometimes get beached. So here is how you can save them if they do. If the whale is light enough, put wet blankets over it and wait for a helicopter to pick up the whale and move it back to the ocean. If the wale is like a Sperm Whale or a Blue Whale, put wet blankets on it and wait for the tide to come in and quickly pull off the blankets.

So keep your ocean clean and don't allow whaling!

References:
Mom & Dad propaganda

Briarcrest Elementary 3rd Grade Class

Transfer of Heat: The Second Law of Thermodynamics

      Sometimes, it is counterintuitive to think that science does not allow “cold” to transfer. When you hold an ice-cube in your hand, it is most definitely, noticeably, making your hand cold! Yet, you have to wonder what is actually happening as the temperatures in both your hand and the ice-cube change.

      The second law of thermodynamics can be stated several ways and can even apply to more than just heat. We are going to stick with heat (thermal energy) because it makes me happy to stay consistent with “Thermo(heat) Dynamics(flow).”

      Before I jump into the definition of the second law, let me briefly explain the first law of thermodynamics: Energy can change form and travel but the quantity of energy is always the same. This is a brief explanation and is considered the happiest of the laws; should this be the only thermodynamic law, all the world’s energy problems would be solved! We would never have to re-fill our gas tanks, or pay for electricity...but this is for another post and I will bring you down a notch with the second law anyway.

      So, what is the Second Law of Thermodynamics already?! Well, simply put:

“A transformation whose only final result is to transfer heat from a body at a given termperature to a body at a higher temperature is impossible. (Postulate of Clausius)” (Fermi, 30)

      Ahem. Come again? Well, in the genius words of Flanders and Swann (musical duet from before my time):

Heat won't pass from a cooler to a hotter

You can try it if you like but you far better notter

'Cos the cold in the cooler will get hotter as a ruler

'Cos the hotter body's heat will pass to the cooler

Just Listen:

      

AHEM. Okay okay: Heat cannot spontaneously flow from a colder location to a hotter location.

      Thus, the ice-cube (you remember the ice-cube in the first paragraph?) is receiving the heat from your hand, not transferring “cold” to it... And your hand will continue to transfer this heat energy until it and the ice-cube are in “thermal equilibrium.” Which will either be when the ice has melted (in most cases) or when your hand has turned to ice.

      Hey, let’s talk about that second scenario real quick! Also known as frostbite, why on earth would the heat from your hand not melt the ice-cube before all of its thermal energy has been transferred? Well, in most cases, it is due to the speed of transfer. If the ice is so cold (due to size, or make-up, i.e., dry ice or liquid nitrogen) that there is a rush of transfer from your hand too fast to allow your body temperature to catch-up with the transfer, then you end up frostbitten. If that temperature is not raised in time to save the tissue, it causes permanent damage.

      Now, back on topic. There are three ways in which this transfer can take place: Conduction, Convection and Radiation.(Bloomfield, 211)

Conduction: Heat-flow through a stationary material. The atoms and molecules of the material are not “flowing” but the heat is... through vibrations of said atoms.

Convection: This is when heat is transferred through fluid. For instance, fluid air (moving air) can  carry heat from a hotter object to a cooler object.

Radiation: The transfer of heat through electro-magnetic waves (see previous blog post on microwave ovens).

      To imagine these transfers on a molecular and atomic level:

Conduction is a bucket-brigade where the atoms are the brigade and the material in the buckets is heat.

Convection occurs when this bucket brigade is riding on a “train” of fluid.

Radiation is the individuals of the brigade, and their buckets of heat, being carried in photons. J

I know, that last one was pretty much a cop-out analogy, but I might just have to do a completely separate post on radiation...Just know that the sun transfers heat through Radiation.

Now, this is a pretty simplified explanation of the second law. To go deeper, I would get into explanations of friction and other “work into heat” ideas and calories. I would particularly like to dedicate a separate post to calories...note to self...For now, I will leave the second law at this, and remember, “Heat won’t pass from a cooler to a hotter!”

Experiment to be done with adult supervision:

Take two bowls and put a scoop (or two) of ice-cream in each. Have a spoon ready to tasteJ. Pour milk (enough to coat, not so much that it is sopping) onto one of the servings, leave the other alone. Now taste. Pay attention to the temperature of each. What is the difference, if any? Why?

References:

http://en.wikipedia.org/wiki/Convection viewed on 08/6/2011. p. 5.

Bloomfield, Louis A. How Things Work. John Wiley & Sons, Inc. 2006.

Fermi, Enrico. Thermodynamics. Dover Publications, Inc. 1936.

Microwave Ovens

Have you ever wondered how your microwave warms up your food, or worried that this mysterious process might be mutating what you ingest or even that those microwaves are escaping the box and penetrating your insides? Well, hopefully I can shed at least a little light on this magic hotbox and allay, well, some of your fears anyway.

Speaking of light, let me start with explaining what a microwave is. As in the actual, electromagnetic wave. You may have heard that light travels in waves, and that each color has a different wavelength. The rainbow shows the spectrum, and these colors are always in the same order...based on their wavelengths and frequencies. These visible waves are only a fraction of the spectrum. Other electromagnetic waves include radio waves, infra-red, x-rays, etc. (see spectrum below definitions).

Wavelength: Physics . the distance, measured in the direction of propagation of a wave, between two successive points in the wave that are characterized by the same phase of oscillation. Or:

Frequency: the number of cycles or completed alternations per unit time of a wave or oscillation. Symbol:  F; Abbreviation:  freq. Or:

1 Hz means that an event repeats once per second.

To demonstrate where your everyday waves fall on a spectrum, including the microwaves we are preparing to discuss, here is a helpful little picture:

Fantastic. Now we realize that the force we are working with in a Microwave Oven is electromagnetic, and have a basic understanding of the spectrum.

      The most important part of your microwave oven is the Magnetron. This nifty device is what is actually creating the microwaves and sending them into the box. When power is supplied electronically (i.e., plug it in and turn it on), the magnetron produces simultaneous electric and magnetic fields that oscillate at the right frequency to create microwaves. These microwaves emit from the magnetron, and are reflected off metal surfaces: A metal fan sends waves into the oven segment, the metal lined walls of the microwave oven reflect the waves throughout and back and forth.

      So now you have microwaves being reflected around the oven. What happens when you add food? First, let’s look at the make-up of the food you eat. Do you know what is common in almost everything you ingest? It’s water molecules. It is these molecules of H2O that are the key to microwaves increasing the temperature of the object inside the oven. This is due to the fact that these molecules are polarized.

      When the Oxygen (O) atom combines with the two Hydrogen (H2) atoms, it pulls the electrons partly from the Hydrogen…creating a negative charge on the Oxygen end of the molecule. This in turn creates a positive charge on the H2 end of the molecule, and there you have your polarization.

      As the fluctuating electric field of a microwave passes by these water molecules, it causes the polarized water to in turn fluctuate…and at the speeds that they begin to fluctuate, heat is in turn created! The excited water is turning the work energy into heat and that is a thermodynamics lesson for another post.

http://radiographics.rsna.org/content/25/suppl_1/S69/F1.expansion.html

This leaves us with a couple of questions still from the introduction.

Are these microwaves escaping and cooking your insides? The answer is no. Take a look at your microwave oven. All the walls, save the door, are all-metal surfaces. The door is a mesh design of metal and amazingly, those holes in the mesh are TOO SMALL to allow the escape of the microwaves. Fabulous, right?

Are these microwaves mutating your food? Pure water molecules are not going to be changed by the effects of microwaves. That being said, the complex carbon chains that make up the rest of most foods may be affected by the microwaves, but to what extent, I don’t know. If you know, please feel free to post a response, I would love to hear what others have to say!

Experiment:

Try (with adult supervision, if you are a minor) microwaving an ice-cube or ice-cubes. What happens? Can you explain why?

Formula (for the math-happy science geeks):

C = λ(ν) or speed of light = wavelength times frequency

Electromagnetic waves always travel at the speed of light, and therefore, the higher the frequency, the shorter the wavelength.

References:

Bloomfield, Louis A. How Things Work. John Wiley & Sons, Inc. 2006. p 432.

 Fischetti, Mark. How the Microwave Works. Scientific American. Oct 30, 2008.
http://www.scientificamerican.com/article.cfm?id=how-the-microwave-works
viewed at link on Jul 30 2011.

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