st. johnsbury academy: ap environmental science environmental decision making: maintaining the big...

St. Johnsbury Academy: AP Environmental Science

Environmental Decision Making: Maintaining the Big Picture Andy Friedland, Dartmouth College11 July 2012

Goals for my talk today:

Briefly describe my background, involvement with APESand teaching philosophy

Briefly introduce our new environmental science textbook Environmental Science for AP

Connect fundamental course topics in APES to “big picture” decision making that can be informed by life-cycle assessment

Define systemIllustrate how defining system boundaries has a large

influence on the acknowledged “impact” of an action

My background undergrad environmental studies/biology

graduate environmental sciencenow: professor of environmental

science in an environmental studies program

My involvement with APES

1995-1998: I chaired the committee that created APES and developed the first few exam offerings

1998: ~5,000 exams2011: ~100,000 exams2012 ~106,000 exams

2008-2009: I was a member of the College Board CDAC (Curriculum Development and Assessment Committee) which was tasked with re-evaluating APES

Environmental science (in context of APES curriculum) • study of the natural sciences and interactions with

humans

My Teaching Philosophy:

• provide breadth and depth• use quantitative reasoning when it is needed• try to be as neutral (unpoliticized) as possible• use relevant examples whenever possible

This philosophy is well represented in our book.

Our book:

-conveys a modern, synthetic approach that includes systems thinking

-integrates global change and sustainability

-uses quantitative reasoning--this ability is essential to success on the APES exam

-uses relevant examples

-is the only book built from the start for APES

Contains AP-friendly features such as:

Do The Math, Checkpoints, AP-style MCQ,

AP-style FRQ, Measuring Your Impact

Chapter title pages and edges of the chapter pages are color coded to reflect sections listed here, which are similar to the Environmental Science Course Description (Acorn Guide) topics (ES Course Topics)

Obtaining oil from tar sands is much more energy-intensive than obtaining oil from oil reserves in the ground

The statement being made by Hansen and others is: Extracting this energy will require much more energy than conventional oil and release much more CO2 than other energy sources.

Systems appear throughout our book

A System is a set of interacting components where a change in one part of the system affects many others. (Chapter 1)

Chapter 2: Environmental SystemsThe Mono Lake system (Chapter 2 opener) “The largest system that environmental

science considers is Earth.” In systems, matter and energy are

important flows to understand.

Friedland and Relyea Environmental Science for AP* page 29

We define systems by drawing boxes around things

We can create a larger system by considering the source of the fuel that powers this car

Source: Friedland and Relyea Environmental Science for AP*

(the question continues……)

We can evaluate systems

qualitatively and

quantitatively So, 80% X 50% = 40% efficiency for a fuel-cell to generate electricity.

An electric motor is about 80% efficient, so the process of powering an electric automobile from a methane-powered fuel cell is:80% X 50% X 80% = 32%

Compare to coal-generated electricity to power an electric car:36% X 80% = 28.8%

Comparing efficiencies in the home:How to boil a pot of water?

Combust natural gas, wood, animal dung heat food in pot (flame to pot transfer is 50% efficient)

Overall efficiency?OrCook with electricity:

Combust coal or oil, or sustain a nuclear reaction heat water produce steam turn turbine generate electricity to home electric coils on stove top heat food in pot (coil to pot transfer is 70% efficient)

Overall efficiency?

Two ways to power an electric carA reformer generates hydrogen at about 50%

efficiency The efficiency of transfer from hydrogen to

electricity in a fuel cell is about 80%An electric motor is about 80% efficient, so the

process of powering an electric automobile from a methane-powered fuel cell is:50% X 50% X 80% = 32%

Compare to coal-generated electricity to power an electric car:36% X 80% = 28.8%

However, the story changes if you consider natural gas powered electricity (55% X 80 % = 44%) or other sources……

The Well to Wheels Equation: Oil in the ground to the gas tank

US Dept of Energy http://www1.eere.energy.gov/vehiclesandfuels/facts/2011_fotw686.html

Fuels used forelectricity generation in the United States, 2009.

There is large regional variation in fuel mix

Chapter 12MYIpage 341


WH Freeman, 2011, Chapter 2, page 38

Is ethanol really carbon neutral. Does it contribute 0 grams of fossil carbon to

the atmosphere?

Source: Friedland and Relyea Environmental Science for AP* page 376.

Source: Friedland and Relyea Environmental Science for AP* page 376.

3,036,000 kJ

Fossil fuel energy must be used to grow corn

Fossil fuel energy is used to:

power farm equipment produce chemicals, irrigatedry grain, and more…..

8,545,000 kJ are used on the farm to grow one acre of corn

…and to produce the ethanol

Energy is used to:Transport corn &

ethanolHydrolyze starchDistill alcohol

21,636,000 kJ are used to convert corn into ethanol and distribute the final product

Coal

The energy contained in ethanol is just a little more than that of the inputs

Ethanol is usually mixed with gasoline to produce a fuel for vehicles

1 acre of corn produces 375 gallons of ethanol, which contains 33,217,000 kJ of energy (a surplus of 3,036,000 kJ).

And useful side-products are made

Side-products include:Distiller’s grainCorn oilCorn gluten

To produce these products from scratch would take 5,390,000 kJ, so credit is given for these

Sample Qualitative exam question Fall, 2011:

a. My environmental friends tell me that drinking bottled water is bad for the environment. I don't understand: I know that bottled water is clean so it must be good for me, right? And I always recycle my plastic water bottles. So what's the problem? [identify two different problems] 1) It takes energy (mostly oil) to manufacture a plastic bottle, fill it with

water and then it takes a great deal of energy to transport bottled water to stores and consumers, especially when you compare this quantity of energy to the minimal amounts needed to obtain the same volume of water from the faucet. [this answer assumes that the water from your faucet is clean and safe to drink; there is no guarantee that bottled water is any cleaner than your tap water].

2) Plastic bottles, used once, can become a solid waste problem if disposed of in landfills, they can become a plastic pollution problem, potentially endangering wildlife if not disposed of properly, and even if recycled, they require energy to transport and recycle, and they are typically not part of a closed-loop recycling process. So they may become carpeting or polar fleece but will not be recycled into a new plastic bottle.

Sample calculation problem Fall, 2011

Problem: Bottled water sales in all of the Dartmouth Dining Service cafeterias last year were approximately 600,000 units. Assume that these were all 1-liter plastic bottles, which when full weigh 1 kg. Also assume that these water bottles were brought by truck an average distance of 100 miles from a bottling plant to Dartmouth. Fuel energy needed to move 1 metric ton (=1,000 kg) of freight 1 mile. Source: US Department of Energy (converted from Btus) Truck 4.3 X 106 Joules (4,300,000 Joules)Rail 3.5 X 105 Joules (350,000 Joules)Cargo ship 6.0 X 105 Joules (600,000 Joules) (a) (2 points) How much energy in Joules was needed to move water bottles to

Dartmouth Dining Service last year?(b) (2 points) The energy content of 1 liter of diesel fuel = 3.6 X 107 Joules (36.4 million Joules). How many liters of diesel fuel were used to move the water bottles to Dartmouth Dining Service?(c) (1 point) How many one-liter bottles of water can be moved from the bottling plant to Dartmouth with one liter of fuel?

Food miles/carbon miles

(a) (2 points) How much energy in Joules was needed to move water bottles to Dartmouth

Dining Service last year?(b) (2 points) The energy content of 1 liter of diesel fuel = 3.6 X 107 Joules (36.4 million Joules). How many liters of diesel fuel were used to move the water bottles to Dartmouth Dining Service?(c) (1 point) How many one-liter bottles of water can be moved from the bottling plant to Dartmouth with one liter of fuel?

a) If the bottles are all 1 kg, and if moving 1000 kg 1 mile by truck takes 4.3 x 10^6 J, and if 600,000 bottles are moved 100 miles, then

4.3 x 10^6 J /1,000 kg-mile X 600,000 bottles X 1 kg/bottle X 100 miles then = 2.6 x 10^11 J

b) Since there are 3.6 x 10^7 J in one liter of diesel fuel,

2.6 x 10^11 J divided by 3.6 x 10^7 J/L = 7200 L

c) Since it takes 7200 L to move 600,000 bottles, the number of bottles that can be moved with one liter of fuel is 600,000 bottles divided by 7200 L, or 83 bottles per liter.

“Last year my class pass rate was below the national average and I felt I had let my students down.

I was lucky enough to be able to adopt your new text this year and I used it with one class. I taught it cover to cover. I appreciated the parallel structure with the Acorn objectives provided by College Board. Thank you for a wonderful textbook!

My kids completed every Multiple Choice question at the end of each chapter….. The students told me these were helpful.

My students also completed every “Measure Your Impact.” I appreciated the applied calculation practice in every chapter…….” Source: a teacher

Questions or Comments?

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