Final Day and Reflection

The last day of our trip included a third and final water quality test of the Greenbrier River and a tour of a railroad museum in Clifton, Virginia.
The water testing indicated the water quality was "good" for all three locations of the Greenbrier River.  These tests were uniform in what was tested:  temperature, dissolved oxygen, turbidity, conductivity, and pH.
The tour of the C&O Railroad Museum in Clifton, Virginia was both informative and very enjoyable.  The staff were extremely helpful and even gave us a ride on a model train.

In the end, I hope this blog helps to serve us in our classroom.  The friends and experiences of the week will continue to play a role in our ongoing discussions.  Moreover, this blog was an attempt on my part to relate each of the major concept areas we cover to the experiences of the of this project.  Most physics texts cover Motion, Forces, Work and Energy, Momentum and Collisions, Impulses, Thermodynamics, Fluid Mechanics, Rotational Mechanics, Waves and Optics, Electrcity, Magnetism, and Modern Physics.  Of these, only Magnetism was not addressed through my experiences with this project and discussed in a blog entry; I alone bear the burden for not having it addressed.
I hope you have enjoyed this experience as much as I have.  I do look forward to our continued collaboration, for this good luck it's not good-bye.

The Mountains of West Virginia and Pascal's Principle

Some of the most memorable experiences of our trip were the breathtaking views at higher elevations.  We visited Bald Knob and Gaudineer Knob; both views were something to behold with respective elevations of roughly 4800 feet and 4430 feet above see level.  These views were remarkable, and the physics we can derive from them is paramount to developing a better understanding of fluid mechanics.  Specifically, we will entertain Pascal's Principle.
Pascal's Principle is usually stated as the pressure in a fluid is transmitted undiminished throughout the fluid.  Yet, this also tells us that the height or depth within the fluid also determines the absolute pressure exerted.  Quantitatively, this is written as P = «P» + pgh:  Pressure is equal to atmospheric pressure plus density of the fluid times gravity times height.  This height element is why our ears "pop" when ascending or descending heights quickly.  Our bodies are attmepting to equalize the pressure inside our body with the surroundings.  The trip up to Bald Knob was on a Shay Locomotive and took close to an hour and a half for a distance of eleven miles.  This rate of ascension was gradual and did not cause my ears to "pop, as they did when driving up to Cathedral State Park.
Here are a couple of questions to consider, each having its answer within the noted equation above:
1.  Why are there fewer air molecules with an increase in height?
2.  From the equation, why would "going down" equate to an increase in pressure?

Water Quality Testing and Archimedes Principle

Our group conducted water quality tests in the Greenbrier River today.  These tests included dissolved oxygen, conductivity, total dissolved solids and pH.  A fellow teacher made the mistake of asking why certain a rock would sink but a "larger" piece of wood would float; physics to the rescue.
Remember folks that fluid dynamics plays an important part of our daily life.  And for you AP students, fluid dynamics accounts for roughly 12% of the AP Physics B exam.  As such, let us entertain one of the key concepts of this study.
Archimedes principle simply states that an object is buoyed up by a force equal to the weight of the fluid it displaces.  Quantitatively this can be written as Fb = mgf (force buoyancy is equal to mass times gravity of displaced fluid).  However, we should remember that mass is equal to density times volume.  Thus, we can think of the buoyant force as being equal to the density of the fluid times gravity times volume.  The force the object applies downward is equal its mass times gravity (mg).  If the object floats, the buoyant force must be equal to the weight of the object (mg).  We can set theses forces equal and the density substitution and arrive at this: 
volume fluid     density of obj
___________  = ________________
volume obj       density of fluid
This equation will serve you well, as test writers routinely will as you to determine the volume of the object submerged.  It is equal to the volume of the dispaced fluid represented in this equation; I assure you this will be asked.  Let' see an example of what to expect.
A wooden cube  with a density of 650 kg/m^3 floats in fresh water.  If an edge of the cube is 200 cm, what level or height of the cube is submerged?
Wood clearly floats well due to its density.  It is no wonder most of us have seen logs travelling by way of water.  And, its nothing more than a little physics making our lives easier.

Shay 11 and Newton's 2nd Law

Our group had a wonderful experience today.  We rode a Shay Steam Locomotive to the top of Bald Knob, elevation 4730 feet.  One the more interesting physics concepts that jumped out at me was the instances when the train would begin its motion and come to a rest. 

With some scrutiny, you could recognize the coupling between the cars and hear a "clank, clank, clank" when starting and stopping.  This brought to my mind the essence of the great. Isaac Newton and his 2nd Law of Motion.  We are most certainly familiar with the notion that F=ma.  Yet, I think it is imporant to remind ourselves that this not exactly what Newton said in his masterpiece Principia.  More precisely he said that the sum of the impulses acting on a body is equal to the net change in the bodies momentum. We of course quantify this as F delta t = delta p.  This change in momentum for a train of course must huge, as mass is being increased with each additional car and with a change in the velocity.  The key to this is really a term we use often and is in our equation.  It begins with "t" and rhymes with "ime"; yes, it is time, time, time. 

A force applied during a greater period of time will equal a greater change in momentum and this is what is needed to start or or stop.  So, the next time you hear a train go "clank, clank, clank" I want you to think Newton and his 2nd Law of Motion.

Here is a sample. If a train with a weight of 800 tons wants to achieve a velocity of 10 km/hr, how much time must be allowed if the maximum tractive force of 16000 Newtons?  Mind your conversion and remember what weight is.

Colonial Millworks and the Physics of a Laser

Today we visited Colonial Millworks in Beverly, West Virginia.  This plant focused its energy on floor mouldings and cabinet mouldings.  Though the plant revealed many physics concepts we will encounter in class, there was one concept that caught my attention more so than the traditional mechanics applications we would typically discuss - LASER.  Yes friends, the plant incorporates lasers at various saw-stations for alignment in the process of making the most accurate cut.  But, what really is a laser?

LASER is an acronym which stands for Light Amplification by Stimulated Emmission of Radiation.  If an atom absorbs energy it will enter an excited state.  The atom, however is like most thinks in nature and desperatly wants to stay in comfortable equilibrium and so return to its natural ground state.  To do this, it will emmit light energy in the form of a photon. We should remember from chemistry that the energy of a photon is equal to Planck's Contant times the frequency of the photon:  E = hv.  A laser plays on this emmission of energy.

Stimulated emmission of a photon is the essence of what we "see" as a laser.  When an emmitted photon strikes an atom in an excited state (absorbed energy) two photons can be released to strike two more excited atoms.  This process can continue to grow and replicate itself.  It is important to note that these photons are all in phase; they have the same wavelength and frequency causing a large amplification of the light/radiation, and now we have a laser.  Since they do have the same wavelength and frequency the laser appears monochromatic or of only one color; this will usually be red or green like the lasers seen at Colonial Mills. 

A point of interest is the timing of this blog post.  I just received an email last night from a friend who pointed me to a story where at Lawrence Livermoore a new laser generated 500 terawatts which would be about 1000 times more power than the entire US would use at any given moment.  It also generated 1.85 megajoules of enegy; this is 100 times more than any previous laser. The scientist are attempting to use the laser to master clean nuclear fusion which would solve all future energy problems; it takes an enormous amount of energy to overcome the repulsive force between positive nuclei.

So, from trying to solve our dependency on fossil fuels, to making sure your cabinets line up correctly, physics is constantly changing the world in which we live.  Can you think of any other applications of a laser?  I think you will be surprised just how dependent we are on Light Amplification by Stimulated Emmission of Radiation.

Physics at Hamer Pellet Fuel

This morning we visited Hamer Pellet Fuel in Elkins, West Virginia.  This facility solely produces wood pellets common for wood pellet stoves.  This was an excellent opportunity to see several of the physics concepts we examine in application.

Let's begin by examining the blue cylinder seen in the picture section which turns and helps dry the saw dust used in the making process.  Our guide informed us the drum cylnder weighs approximately 110,000 lbs.  The estimated radius of the cylinder is 20 ft.  If the cylinder has an angular speed of 1.57 radians per second.  This speed must be maintained in order to complete the drying process.  The cylinder is rotated by four trunion wheels.  What total torque does the cylinder experience due to the rotating trunion wheels? This is an AP level question folks.  Remember to think of how we define torque.  The moment of inertia (I) for the cylinder is given by I = 1/2MR^2.

Now let us look at the dreaded incline plane. The picture section shows an incline with rollers used to move pallets loaded with bagged pellets at a weight of two thousand lbs.  With angle of the incline being rougly 15 degrees what is the final velocity of the pallet if it takes four seconds to move down the incline? The pallet is at rest initially.  The operators are using the incline, gravity, the pallets own mass and the rollers (eliminate friction) to move the pallet unassisted over a specific distance where the pallet is picked up by a forklift and deposited elsewhere. No man, no electical or computerized element are used.  Only a simple machine and physics.

Day One of Trip

Greetings folks!  Today was the first day of our excursion throughout West Virginia studying the timber and rail industries.  We spent the bulk of our time at Cathedral State Park. 

This is a remarkable sight which is in fact considered virgin timber; it has never had an ax brought against it.  Specifically, this area is predominantly composed of Hemlock.  Hemlock is an Evergreen tree that grows between 18 and 21 meters in height and makes its habitat in soils that are acidic; this is described as having a pH (Power of Hydrogen) below 7; alkaline describes a pH level above 7.  The numerical values can be determined by the equation pH = -log 10base [H+]. Qualitatively, pH canbe desribed as the molar concentration of hydrogen ions present.  The insturment typically used for this test consists of a a wire coated in silver chloride within a diluted hydrocloric acid solution surrounded by a glass membrane.  This membrane seperates the solution from what is being tested and determines the potential devoloped across the glass.  This can be shown to be proportional to the hydrogen ion concentration on the two surfaces.  Soil sample tests were conducted using a Vernier Labquest and were confirmed at a pH of roughly 4.1.

In addition to soil testing with pH confirmation, we worked in teams to determine the board feet of a tree.  Board feet is an industry term which estimates the amount of "usable" wood from a tree.  This proces includes using basic geometry and angle studies to determine the volume of a tree.  Volume is equal to area  times height.  We found the area by measuring the circumferene of the tree and used this to determine the radius.  With the radius known the area at chest level was determined.  A clinometer and the tangent function of the corresponding angle made and a distance of 66 feet from the tree were used to calculate the height.  The tree we measured was estimated at 1441 board feet.

This was a great first day.  Actually seeing a sight that had never been logged was exciting.  Yet, what struck me the most was the acid level of the soil and lack of life therein.  There really was not much living in this area aside from specific trees, mostly Hemlock, and ferns.  Cellular functions can only take within certain pH parameters and my best hypothesis is that a combination of reduced sun, a major canopy exists here, and acidic soil make this ecosystem limited in the number and types  of species it can sustain.

Take care, and I will bring you up to date on day two tomorrow.

Linear Expansion Follow -Up

Our last discussion entertained expansion of steel rails for a railroad due to the addition of heat.  So did our railroad engineer design the rail system correctly, or does this person need a refresher in physics?  Well, there was 2.5 millimeters between the rails.  Unfortunately, the linear expansion for the steel used was given at 1.2*10^-5 C^-1 and the original length of the rails were 12 meters long.  A 50 degree change in temperature could lead to linear expansion of .0072 meters or 7.2 millimeters; our engineer may have just cost his company quite a bit of money and should probably look forward to a physics refresher.

Thermodynamics, Railroading and Linear Expansion

My last post entertained briefly the First Law of Thermodynamics.  Such a concept permeates most all systems including what is often referred to as a closed system.  Within a closed system, matter can not cross a set boundary - enter or leave.  Most textbooks refer only to energy as being able to cross the set boundary within a closed system.  We demonstrated from earlier posts that work and energy were in fact synonomous, and as such, we can include work as being able to cross the set boundary of the system; this validates both th qualitative and quantitative definitions of the law: 1.  conservation of energy; 2.  delta U= Q-W - change in internal energy is equal to energy/heat added to the system minus the work done on the system.  Let's discuss why most solids expand when energy/heat is added.

As a child, I can remember my grandmother running hot water over the lids of jars to help open them.  This practice is based on the concept of linear expansion.  When energy/heat is added to most solids the molecules of the material speed up their interactions, push outward and the solid expands.  Quantitatively, and from a linear perspective, this is given by delta L = «a»L delta T - change in length is equal to the coefficient of linear expansion times the original length times the change in temperature. This «a» or coefficient of linear expansion will almost always be given in a stated problem.  For a good list of coefficients of this type you can go to www.engineeringtoolbox.com and search for coefficient of linear expansion for materials.  Here is a railroad example.

You are reviewing some specifications on a newly constructed railroad.  As you are examining the 12 meter long rails, you notice there is 2.5  millimeter gap between the rails. The coefficient of linear expansion for the steel used in the rail is 1.2*10^-5 C^-1; the units for coefficient of linear expansion are 1/C or C^-1. You check the almanac and find that the normal temperature can increase as much as 50 degrees Celsius on a hot day.  Did the chief engineer wisely design the rail system or should he retake high school physics?

Next time, we will.check the answer to this and tackle some other thermodynamic issues with rail transport.

www.engineeringtoolbox.com

Clearcutting Controversy

Here is a link to an interesting article from Clemson University which discusses the controversy surrounding clearcutting.  As with most pursuits of humankind, rarely if ever can we deal in absolutes.

http://www.clemson.edu/extfor/timber_production/fortp19.htm

Tree Identification

Tree identification will be an important part our project.  I have chosen to link  to a business named Industrial Timber and Lumber.  This group has several locations.  Yet, what pulled me to them was that they have two major sawmill operations in Vinton County, Ohio only about 45 minutes from my home, and a huge kiln drying operation in Marlington, WV.  I believe this is close to Elkins, WV.  I plan on visiting the sawmills
inthe next few days and hope we can stop at the Marlington location during our trip. 

Their site offers great deal of information on various species.  This includes tree identification by leaf, charted information about relative working properties for each wood, sample grade photos, and an overview of each species.  Incidently, information about each location's production offers some good insight into the productivity of our region. 

http://www.itlcorp.com/Species.aspx

First Law of Thermodynamics and Steam Locomotives

Recently, we have discussed work and energy concepts.  Let us now build upon those concepts within a basic steam locomotive.

We know from previous posts that there is more than one way to define work.  I am going to now offer another definition.  Work equals force times distance - W=Fd, is our most common definition. We also know this is equal to a change in energy.  Yet, if we consider pressure is equal to force divided by area - P=F/A, a common concept learned at least by middle school.  An easy manipulation tells us that F=PA.  Substituting this into our equation yields work equals pressure times area times distance - W=PAd.  But, area times distance is a definition of volume.  So work is equal to pressure times a change in volume - W=PdeltaV.  This concept of changing volume at constant pressure to move a piston is precisely the mechanism behind basic steam locomotive operation and owes its origination to the 1st Law of Thermodynamics;  the change in the internal energy of a system is equal to the heat added to a system minus the work done on the system - delta U=Q- W.

Our locomotive burns coal or oil to heat water. The water eventually changes to high pressure steam which increases its volume and expands pushing a piston within a cylnder.  This explains why locomotives must take on water periodically as its water supply is constantly be turned to steam.  The piston is connected to a rod apparatus which connects to coupling rods which move the wheels.  Incidently, the steam exaust is simply released by a valve under great pressure which accounts for the "choo choo choo choo" we hear and, the piston returns to its original position ready to be pushed again by pressure and volume expansion.

We now should begin to recognize some basic relationships among work, energy, power, and force with a locomotive.

Energy Follow-Up

My good friend Steve Beckelhimer posed an interesting question as to whether I could relate a problem on the energy concept I spoke of last time to rail and timber transport.  Absolutely!  If we consider a train in motion on a track, an important engineering principle is continuous tractive force.  This is a force applied by an object pushing or pulling on another causing a change in velocity.  This tractive force is inversely proportional to the velocity of the train.  As the train speeds up, more fluid resistance
impedes the tractive force of the train.  How can we quantify this continuous tractive force?  Power is needed to propel the train.  Power is the transfer or use of our good friend energy during a rate of time.  Since energy and work are synonymous (demonstrated in the last blog entry) we arrive at the traditional definition of power=work/time -P=W/t.  But we also know work is equal to force times distance on object moves - W=Fd.  So, power is also equal to force times distance divided by time - P=Fd/t.  Distance divided by time is velocity, which was being solved for on the physics question in the last posting.  Now, we have arrived at power is equal to force times velocity - P=Fv or F=P/v.  This is the equation engineers use to calculate the continuous tractive force for a train and it is derived from the concept of energy and its partner work.

Question from Physics Final

Energy is a very robust and powerful concept.  Most early concepts in a physics deal with Newtonian Mechanics (motions, forces etc.).  However, when we start to look at the world of Quantum Mechanics, we must surrender some of our most dear and cherished  understandings that have served us so well.  Early experiments at the sub-atomic level raised some interesting questions.  One was that there seemed to be a loss of energy in some fission experiments.  Niels Bohr, the father of the atom, proposed that maybe the law of conservation of energy did not hold up at the sub-atomic level.  Wolfgang Pauli put forth that he would place his money on the conservation of energy and postulated that there was some particle that was not seen which accounted for the mass/energy.  Today, we know that Pauli was correct and the neutrino (similar to an electron without a charge) is a fascinating particle which accounted for the energy in those experiments. As such, it is important for our students to have firm understanding of the concpet of energy and for that matter its relationship to work.

Here is a question I offered my seniors on their final to asses their consolidation of energy and work:  A freight train with a mass of 4*10^7 kg experiences a net force of  6.8*10^7 N and moves a distance of 110 meters.  If its initial velocity is 5.5 m/s, what is its final velocity?  How we define work and energy solves this problem.  W=Fd, F=ma and d=vt this is average velocity vf +vi/2.  Now remember that acceleration is change in velocity divided by change in time.  This together gives us W=m (vf-vi/t )*(vf+vi)t/2. The t's cancel and dividing by 2 is like multiplying by 1/2.  This yields W=1/2mvf^2 - 1/2mvi^2. 1/2mv^2 is the definition of kinetic energy.  Thus, work is the change in kinetic energy.

Clear Cutting?

Greetings!  I was wondering if any of my fellow bloggers could tell if these pictures offer an example of clear cutting?  I must admit the pictures are not from WV, but from Ohio.  I was driving north on Route 7 in Gallia County when I came upon this site.  Lushes and green and then boom, nothing.  It looks like the area which goes way back over the hill has been carpet bombed.  Is this a common practice?  I suppose if you wanted a biologic which needed massive amounts of sunlight to grow in abundance this might be viable.  I just don't know.  If you have any ideas, post back.  I will try to get some more photos today.

K and M Current Photos

Here are some current photos of the railbridge near Pt. Pleasant.  There are several factors that go into bridge design and have a direct relationship with physical science.  Students should remember that Newton's 2nd and 3rd Laws must always be accounted for together when analyzing a situation.  Consider a train moving over the railbridge.  The train exerts a force on the bridge, its weight: F=ma (acceleration is gravity).  The bridge is in equilibrium, it is not falling or accelerating down.  Newton's 3rd Law helps to explain that the bridge must be appyling a force equal to and opposite in direction of the force the train applies and, their net force must be 0 so we say - Fnet = Ftr +Fbr = 0.  The acceleration due to gravity should have a negative sign for indication of direction.  This would be very appropriate for 9th graders.  11th and 12th graders could up the game by incorporating Hooke' Law: F = -kx and Young's Modulus: E = Stress/Strain.  I will discuss those on my next blog posting.

K and M Railroad

I had an interesting day in the Gallipolis/Point Pleasant area.  I visited a railroad bridge connecting Ohio and West Virginia that was part of the K and M Railroad.  The Kanawha and Michigan Railroad ended up running into Fayette County, and it connected the Great Lakes with West Virginia.  Interestingly, located in very close proximity to this was the original Silver Bridge which collapsed in 1967 killing 46 people; a replacement, the Silver Memorial Bridge, was completed in 1969 at distance of roughly 1.5 kilometers down river.  Many of us are familiar with the Mothman tales related to the bridge.  Yet, for me, I still remember my father telling the story of how he and my mother were at the original Bob Evans eating when it happened.  They were going to go dancing at club in Point Pleasant, but dad wanted a Dutch Boy sandwhich from Bob Evans; a Dutch Boy was a cheeseburger he was fond of.  While they were eating, my Uncle Francis arrived saying grandma had sent him to look for dad because that !!??!!?? Silver Bridge had fallen. 

Here are the two bridgs next to one another.  I find it intersting that they were so close to one another.

THE BEGINNING

Greetings my friends!

This summer, I will be lucky enough to participate in a project in which myself and several other teachers from Cabell County Schools study the influences of railway transportation and forestry in the state of West Virginia.  This the first of several posts to my blog which will follow our group through the process.

Many of my friends from the project of last year have returned for a new adventure.  Yet, I would be remiss if I did not mention the addition of one Brian Mcneel to our group.  With the departure of Robert St. Clair, former chemistry teacher at Huntington High School, this old viking would have been on the prowl for new prey on which to play my many practical jokes. Fortunately, it did not take any time at all to realize how Brian would cleary be able to fill such an imperative role.

We have had three training sessions so far, with the intent of bringing us up to speed about the science behind timber harvesting in the state.  Moreover, one of our esteemed leaders, Steve Beckelheimer (the same hairy legged creature from last year), has spent much time explaining the biological perspectives of timber.

We have had two guest speakers so far.  Each gave us perspectives on railway transportation with link to Cabel County.  Tonight, we will be having class and an update will follow.  I just hope Brian Mcneel decides to finally comb his hair.

William