billion years_2023_1 (2).pptx

Mini Quizzes (online, multiple, 10%) The quizzes are intended to self-assess your understanding of the material and the readings. You will have the opportunity to take each quiz 2 times during the period of availability, with the higher attempt counting towards your final grade. Quizzes are ope...

Mini Quizzes (online, multiple, 10%) The quizzes are intended to self-assess your understanding of the material and the readings. You will have the opportunity to take each quiz 2 times during the period of availability, with the higher attempt counting towards your final grade. Quizzes are open-book and available for 3-5 days. Assignments (3, 30% total) In the assignments, you will blend mathematical calculations with some basic assumptions to gain insight into global-scale problems. You will also provide written answers on important Earth System concepts. Tackling the assignments is where much of your learning will take place and they will take several hours to complete. Ask for help early if you are confused and make note of the anticipated due dates in the table above. Assignments are open book. If you use resources other than the course material, cite your sources (any style). Assignments will be posted and submitted on Brightspace. Tests (3, 60% total) The three tests are intended to test your general understanding of the subject matter. The tests will include long & short answer questions, and some calculations. Tests are closed book. The first two tests will be written in person during regular class time. The third test will take place during the Dalhousie exam period. Do not make any final travel arrangements before the final exam schedule has been posted by the registrar’s office. Students must receive a passing grade (50%) on the final exam to pass the course. Components of the Earth System  A system is an entity composed of diverse but interrelated components (=“parts”). The components function as a complex whole. They are interdependent. Components: reservoir of matter reservoir of energy system attribute (T,P) a subsystem System Couplings and Feedback Loops • A link that allows the flow of information between components is called “coupling”. • a coupling is “positive” when a change in one component leads to a change in another component in the same direction. a coupling is “negative” when a change in one component leads to a change in another component in the opposite direction. System Couplings and Feedback Loops When couplings create a round trip -> feedback loop.  positive feedback loops amplify the effect of disturbances. negative feedback loops diminish the effect of disturbances. How to determine the sign of the loop ?  odd number of negative couplings -> negative feedback loop even number of negative couplings -> positive feedback loop The Carters had a Systems problem…. • Jimmy Carter was President of the U. S. from 1977–1981, before Ronald Reagan. • He was awarded the Nobel Peace Prize in 2002. • Despite having all of the resources of the nation at his disposal, Jimmy had a hard time maintaining a comfortable temperature at night. http:// www.georgiaencyclopedia.org/ media_content/m-953.jpg • Jimmy and Rosalynn used an electric blanket with a dual The Carters had unwittingly created a positive feedback loop. proper usage Equilibrium States: • A system is in equilibrium if it does not change unless it is disturbed. • Equilibrium states can be stable or unstable. • A system is in a stable equilibrium when its response to a modest disturbance returns the system to its initial equilibrium state. • A system is in an unstable equilibrium when its response to a disturbance moves the system to a new equilibrium state. Equilibrium States: The ball analogy  Balls will seek out low points on a wavy surface.  Low points are analogous to stable equilibria.  High points are analogous to unstable equilibria.