Revised

I actually found 8 loops. 

Delays: I think there should be a delay somewhere between Altitude and Throttle Setting because human reaction is involved.  I think it would go between Goal Descent Rate and Throttle Setting. However, this wouldn't be a huge delay because of the short period of time we're talking about with rocket launching. I think the rest of the variables feed on the others (and are machinery-based), making things instantaneous.

I believe, based on the variables the human operator would be focused on at each point of the rocket flight, the outer parts of the CLD would be the focus at the beginning of the process and the inner parts of the CLD would be the focus at the end (Descent Rate, Gravity-related variables, Air Density, Air Resistance, and Altitude).  Also, the gravity, air density, and air resistance wouldn't come as much into effect until the rocket closed in on the ground.  Remaining fuel would be closely observed for the entire flight. 

Below is the table that outlines the variables and progression of each of the loops.  As you can see, because I didn't realize what the throttle and the thrust meant (ie. increasing the throttle and the thrust actually means the rocket slows down), two of my loops should actually a different type of loop. 

Loop ID (i.e. R1, B1, etc)	Loop name	Description of the role that the loop plays in the flight of the rocket. That is, “tell the story” about each loop.
B1	Force of Air	The Altitude (decrease) has an effect on the Air Density (increase) which then impacts Air Resistance (increase) and then the Descent Rate (decrease) which leads back to Altitude (increase – it’s not really going back up in the air, but that’s the closest approximation of what it does)
B2	Gravity Pulls	The Altitude (decrease) leads to a difference in Air Density (increase) which changes the Acceleration due to Gravity (decrease) and changes the Descent Rate (decrease) and back to Altitude (increase).
R1	Close and Closer	The Altitude (decrease) leads to a difference in Force of Gravity (increase) which changes the Acceleration due to Gravity (increase) and changes the Descent Rate (increase) and back to Altitude (more decrease).
R2	Fuel Running Down	Remaining Fuel (decrease) leads to a change in the Rocket’s Mass (decrease) which then leads to a change in the effect Gravity has on the Rocket (decrease) and thereby, affecting the Acceleration due to Gravity (decrease).  This changes the Descent Rate (decrease) and the change in Descent Rate changes the Altitude (increase – really this is the rate the altitude is changing).  As the Altitude changes, the Goal Descent Rate also changes (increase) and affects the Throttle Setting (decrease) and therefore the Fuel Burn Rate (decrease) leading to a change in the Remaining Fuel (increase – actually a rate again, the fuel is not actually increasing).  SO this is actually a balancing reaction.  I didn’t understand what the engines (and therefore the throttle) were supposed to be doing until today in class.  This should really be B7, I think.
B3	Descending	As the Altitude (decrease) changes, the Goal Descent Rate also changes (decrease) and changes the Throttle Setting (increase) and the Fuel Burn Rate (increase).  As the Fuel Burn Rate changes, the Thrust (increase) and Upward Acceleration (increase) also change.  This leads to a change in Descent Rate (decrease) and a subsequent change in the Altitude (increase).
B4	Thrusters on Full	As the rocket’s fuel changes – Remaining Fuel (decrease) – the Goal Descent Rate (decrease) changes and leads to a desire to change the Throttle Setting (increase) and the Fuel Burn Rate (increase) also changes.  This leads again to a change in the Remaining Fuel (decrease).  So, this should be a reinforcing loop instead – again, my idea about the throttle was confused. R3 is what it should be called.
B5	Descent Resistance	As the Descent Rate (increase) changes, the Force of Air Resistance on the Rocket (increase) also changes.  This leads again to a change in the Descent Rate (decrease).
B6	Fuel Up Fuel Down	The Remaining Fuel decreases as the rocket continues its descent and that decreases the Rocket’s Mass.  As the mass changes, so does the Upward Acceleration but it increases.  This decreases the Descent Rate and “increases” the Altitude and the Goal Descent Rate.  As the Goal Descent Rate increases, the operator wants to decrease the Throttle Setting.  Decreasing the Throttle Setting also decreases the Fuel Burn Rate.  This “increases” the Remaining Fuel.  That progression makes this a balancing loop.

Rocket Man CLD

Here is what I have but it still doesn't really feel right.

Coastal Erosion and Jetties

Along the East Coast of the US, especially in the Outer Banks and Intracoastal Waterway areas, there are problems with coastal erosion.  The currents along this middle to southern section of the East Coast can be very strong.  The implications of this are the gradual loss of beach area in some locations and many deposits of sand onto other beach areas. 

In this commercial age, the diminishing sand and the encroaching waves would mean the loss of beachfront property and business in the tourism economy.  Business owners and property owners placed pressure on governmental organizations to find a solution to the erosion problem.  What they didn't realize is that the solutions they could think of would either cause new problems or would not permanently fix the current problem.

One of the ideas the government had was to relocate the already relocated sand.  By dredging up sand that was deposited on some beaches and taking it back to the eroded beaches, governmental organizations figured this would at least help the problem.  This process is expensive and has to be repeated often.  However, that's not the main focus here.

Officials decided to build jetties.  The purpose of the jetties, and the assumption behind them, was to block the erosion of the sand.  The whole premise is that even if the sand is eroded down current, it will be stopped by the man made jetty jutting out into the current.  This does make beaches an interesting shape because it is not actually stopping erosion in the first place, it is merely preventing the sand on the beach from getting very far. 

What individuals failed to realize (or didn't put much store in) was that by altering the shape of the coastline, they were also altering the flow of the coastal currents.  The currents are not going to stop just because something is in their way.  Instead, the currents then flow around the jetty, and more sand is eroded from the opposite (down current) side of the jetty.  As a result, a new jetty had to be built to prevent the erosion of the down current beach.  This, as is probably obvious, is a continuing cycle of erosion and erosion prevention. 

The mental model of the officials and others in the community was that by placing something in the flow of the current, the erosion from the beaches would be stopped.  This mental model was insufficient because it failed to take into account where the currents would go after they "ran" into the jetties.  Because nature doesn't necessarily move tremendously fast, the new coastal erosion was probably a delay in the real world model.  As a result, for awhile the mental model of these individuals was confirmed when the sand from the beaches was stopped at the jetties.  By the time the deficiency in their thinking was realized, it would have been too late to change the plan.  Thus, more and more jetties built.

 

I had this idea from multiple classes in undergraduate work.  I wasn't sure where to cite sources as a result.  It's all what I remember from class.  I can thank the James Madison University Department of Geology and Environmental Science.
 

Here are some graphs I found on air and stream pollution:

Air pollution in America over time:



http://english.people.com.cn/mediafile/200912/02/P200912021515392118984617.png

Ocean pollution:



http://waterstse.files.wordpress.com/2011/04/graph_ocean-pollutants1.jpg

Here is a chart that has all the tasks we use water for in our homes - many ways for pollutants to enter the water just from our usage:



http://academic.evergreen.edu/g/grossmaz/ABRASHNM/IMAGES/piegraphs_files/conservation_graphs_files/with.gif

It was hard to find a line graph for water pollution.  I found the following graph pertaining to London's water quality for 1990 through 2008.



http://www.environment-agency.gov.uk/static/images/Research/Figure-3-water-quality.jpg

Human Impacts on Forests

One problem that interests me at this point is the issue of deforestation and the effects it has on the environment.  With greater increases in population, cities grow and the formerly forest environments are no more.  With the decrease in tree populations and overall vegetation, air pollution has the ability to increase even more.  The low amount of concern society seems to have about this issue is alarming.  It is well established that trees and other plants help animals get the oxygen they need.  This includes us, as humans.  The interesting thing is that humans are both the only animals who can understand and observe this fact and the only animals that have a direct influence on the destruction of these resources.  Tree planting programs are starting to be instituted in more places, but cities are also growing and encroaching on as yet unblemished forests.  A variable that would be interesting to observe but would probably be very difficult to quantify accurately is human impacts on forests.  Over time, this has evolved from simply cutting down forests to dumping trash and releasing toxins into the air as well as water sources.  Even the forests that have not been touched by human consumption are affected by the second-hand touch of humanity: polluted streams and air. 

I guess a good variable would be pollution growth - since most of this comes from human interactions with the environment.  The graphs for this sort of thing would probably show an exponentially increasing curve.  (Okay, I'm not sure about exponentially because those curves tend to approach zero, but it would likely look something like that.  The pollution in our air and water is continually increasing because of the waste we create and the exhaust and smoke we release into the air.  I think there would be a steadily increasing trend even into the future, because while more and more people are becoming concerned with the state of the environment, it is difficult to get the entire world onto the same page with reforms that would most likely limit the convenience of day-to-day life.  Today's society is reliant on instant gratification; instituting new transportation and waste management policies would have huge political and societal ramifications.  The beginning of the increase in pollution would be seen around the time of the Industrial Revolution and as more and more advancements are made in industry and technology, those pollution numbers just keep going up.

The parts of the system would include acres of forests and volume of streams (are there kiloliters? I'm not sure how to measure the streams) that are intact and unpolluted; emissions by vehicles and industry; the average waste produced by humans per year; how much clean-up is done every year (so that would be an opposite relationship probably); public opinion for conservation; new policies; and new policies would probably lead to more creative ways of creating pollution.  I think I might be missing some parts, but those were the ones I could readily describe.  Are we going to draw causal loops of our systems?  In this system, as the emissions increase, the areas of unpolluted forests and streams would decrease.  There would also be an opposite relationship between unpolluted area and waste.  As emissions and waste increase, so would public opinion for conservation increase - leading to new policies.  Then would come in the evasion of the new laws and policies.