PDS AP Env Sci 7th Period 2012-13

"Look out any window…"

by derrickwillard

Closed for Business-But Please Check Us Out!

If you have just stumbled upon this blog, note that our class no longer meets and will no longer be adding new content. Feel free to click around and see all that we’ve learned about environmental science this year.

Class of 2013, sorry to say the year is over. I really enjoyed our time together. Best of luck to each of you in college and beyond! -Mr. W

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by derrickwillard

Google Earth Engine: Amazing Satellite Timelapse

Too cool not to share. Amazing use of Landsat Satellite imagery to see how the Earth has changed (for the worse) over the last few decades. Click here to see timelapse imagery of urban sprawl of Las Vegas, Nevada. After that, scroll down to view many of the environmental issues we have studied this year; the drying of the Aral Sea, the deforestation of the Amazon, and the retreat of the Columbia glacier. Stunning. Depressing.

Screen shot of Google Earth Engine showing deforestation of the Amazon Rainforest


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by lindsaybrown
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Would’ve Been Helpful Before the Exam…

Okay so I was on youtube and somehow I came across this Ted talk video. I thought I’d share it because it made me think of what we learned in APES.  This kid basically summarizes a lot of our agriculture unit (CAFOs, GMOs, organic farming) in 5 minutes. It’s a very broad summary, but it may have been more helpful before the exam rather than after… I thought he had an interesting perspective of paying the organic food cost vs. paying hospital costs.


What’s Wrong With Our Food System  –> just click on the link

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by derrickwillard

Climate Change MEGA-POST

Since it is so close to the AP exam and all of you have fulfilled your scribe post obligations, I won’t start the list over. So, here is a collection of links from past classes on global climate change for those that missed class. While written a year or two ago, all the info is still correct and relevant (and a great review):

Intro to Global Climate Change

Global Climate Change

Evidence and Consequences (of the Earth’s Warming)

Solutions to the Earth’s Warming Problem
So, while your text does introduce the concept of carbon neutral it did not mention carbon offsets, which have become a hot ticket in “climate change mitigation.” There are many companies out there now marketing carbon offsets to reduce your “carbon footprint.” Terrapass is a popular one. You can offset one year’s worth of air travel (an estimated 8,000 pounds of carbon emitted) for just $50.60 as of 5/5/2011. Your money goes to support wind farms and methane capture projects-that’s how the carbon is “offset.” Some companies will even plant trees to offset carbon produced by your lifestyle.

So, does this approach really mitigate global climate change or just encourage more “bad behavior” (burning of fossil fuels)? Watch this clever parody of carbon offsetting by a couple of Brits:

*If you want to learn more, visit www.cheatneutral.com

So, what do you think?

*Try www.carbonfootprint.com to for a carbon calculator if you want to assess how much carbon dioxide results from your lifestyle.

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by danielkhordehforosh

Atmospheric problems: Acid Rain and Ozone

  1. Today’s class was divided into two parts: The first part of the period was spent discussing atmospheric problems in regards to Acid Rain and the latter part of the period was spent on discussing atmospheric problems in regards to Ozone.

 Acid Rain- Occurs in the Troposphere


  1. Initially, Sulfur Dioxides and Nitrogen oxides are emitted into the atmosphere through the burning of coal in power plants and the combustion of gasoline in automobiles.
  2. These Sulfur Dioxides and Nitrogen oxides are absorbed by water droplets in clouds and fall down back to earth in the form of rain, snow, fog or dry particles such as salt.
  3. The precipitation falling back to Earth usually has a pH of 5.6.
Formulas for Formation-
  1. NO2 + H20 yields HNO3- Nitric Acid
  2. SO3 + H20 yields H2SO4- Sulfuric Acid
These formulas which we learned at the begininning of the year show how Nitrogen oxides and sulfur dioxides combine with water vapor in the atmosphere to form Nitric and Sulfuric Acid respectively
The biggest problem associated with acid rain is that it lowers the pH levels of lakes and streams which ultimately results in the killing of many aquatic organisms
Direct Damage- Acid rain damages plant and animal tissues leading to death of these organisms
Indirect Damage- Increase in the acidity of the soil causing an increase in leaching which drains the soil of its nutrients which allow for plant growth
Of course just like any other environmental issue, prevention is the key.
-Power Plants need to burn low sulfur coal
-Add expensive scrubber technologies to coal power plants which decrease sulfur emissions
-Add lime to acidic lakes
-Cap and Trade Program- This is a system set up in order to regulate SO2 emissions. Requires use of market forces to drive down emissions by setting up a total allowance of SO2 emissions which can be bought and sold amongst different power plants
Now for the second part of class: Ozone
There are two kinds of Ozone:
Good Ozone-Ozone in the stratosphere-Absorbs and blocks 95 % of UV radiation
  • If U.V would reach us it would cause DNA damage leading to skin cancer in cataracts
 Bad Ozone- Ozone in the troposphere- Increases pollution at ground level
  • Troposheric ozone is a photo-chemical smog component
  • aids in damaging plant leaves along with causing eye and lung damage


Through the addition of CFC’s for use as nonflammable refrigerants our ozone is being destroyed

  • CFC’s breakdown ozone in the presence of U.V light causing thinning of our stratospheric ozone
  • U.V light cleaves the Cl molecule of CFC taking apart our good ozone

Formula for Destruction of Ozone-

  1. Cl+O3 Yields ClO+O2


In order to address the issue of CFC’s thinning out our good ozone, the Montreal Protocol of 1987 was created

  • International treaty designed to protect our ozone layer
  • Goal was to cut the use of CFC’s



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by danielstack
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Automobile Emissions Lab Discussion


From the background notes as well as our discussion many things were discussed on car emissions, pollution in general, and their monitoring.

One emission that is not regulated is N2 Nitrogen Gas because it is consider relatively benign and makes up 78% of our air.

From the data collected, we can see that the newer, more efficient fuel burning cars have the highest CO2 levels given that it is given off with complete combustion.CO2 is currently not regulated but may be in the future given that it is a Greenhouse Gas.

But as it’s opposite, CO will be highest with older cars that release more unbruned fuel make into the atmosphere in the form of this colorless and odorless poisonous gas. As the engine gets warmer form running over time, the better the car will be at burning its fuel efficiently  resulting in higher CO2 levels and lower CO levels.

Hydrocarbons are made up of hydrogen and carbon. In the lab, we tested for butane and propane. These compounds help to contribute to the formation of ground level ozone–a major component of photochemical smog.

Nitrogen oxides (NOx) are very bad and are regualted because they aggravate respiratory problems and contribute to the formation of ozone and photochemical smog. Nitrogen dioxide can also combine with water to form nitric acid (HNO3)–a form of acid rain. Cars dont release ozone so we tested for NO2 (NO2 splits into in NO and O. The lone O combines with O2 forming O3 aka ozone).Catalytic Converters are used as “two-way” converters which combine carbon monoxide (CO) and unburned hydrocarbons (HC) to produce carbon dioxide (CO2) and water (H2O). In our pH test we found that all engines produced a pH between 4-6. The reason that the pH is acidic is because of SOx and NOx. The governemnet has heavily regualted and taken much of the sulfur out of gasoline.

Look at The Know Your Formula sheet to see how all of these pollutants contribute to acid rain, ozone, and the air quality.

Also, we began to discuss how these pollutants are regualted:

The Clean Air Act empowers the EPA to set air quality standards and is the reason that you have to get your car inspected. The Clean Air Act led to the creation of The National Ambient Air Quality Standards (NAAQS) for the following pollutants: NO2, O3, SO2, CO, Lead, and Particulate Matter. Monitor these to provide the public with an air quality forecast and warn those with asthema, emphysema, and bronchitis.

For a good description on why and how catalytic converters are used visit here.

The 6 Criteria Pollutants established by the Clean Air Act that the government monitors (click on each to learn sources and effects): Website here

Air Quality Index (website here)

Photo sources:

The Greenhouse Effect

Photochemical Smog

Car Emmisions Ozone





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by devinredmond

Scribe Post: Air Pollution and Car Emissions

In class today, we started to learn about air pollution and car emissions for Unit 15.

There are two types of air pollution that occur in the troposphere: Indoor pollution (worse) and outdoor pollution(ambient air), but we only touched on outdoor pollution today in class. For outdoor air pollution, we specifically talked about smog–Photochemical and Industrial Smog.

  • Photochemical Smog: Dominated by oxidants such as ozone. Nitrogen based (plus ozone), there is a brownish color to the smog(also known as Los Angeles type), and the source of photochemical smog is mostly from Autos(cars, buses, etc.) from the burning of refined oils.
  • Equation for Photochemical Smog: Hydrocarbons+Sunlight+O2+ CO+ NOx–> O3+ NOx+Organic Compounds+CO2+H2O
  • Industrial Smog: Dominated by sulfur dioxide and sulfate compounds. Sulfur Based (plus particulates), there is a grayish color to the smog(also known as London type), and the source of industrial smog is mostly from industries and power plants from burning coal.
  • Equation for Industrial Smog: SO2+Ca(OH)2–>CaSO3+H2O

After air pollution, we talked about the car emissions that contributes to photochemical smog. From our “Mixture of Normal Air,” 78% N2 and 21% O2 goes into the ICE of the car (Internal Combustion Engine), as well as gasoline. From that, exhaust is created that the government regulates and doesn’t regulate. Together, these make up Primary Pollutants. 

  • Regulated: CO=very toxic. HC= hydrocarbons(VOCs: organic compounds that become vapors at typical atmospheric temps). NOx=nitrogen oxides which reacts with the sunlight to form NO2, NO, and O3(not accounted for). PM=Particulate matter(soot).
  • Non-regulated: N2=inert. H2O=benign. CO2=warming gas+toxins (which is now in debate on regulating).

We briefly touched on All Major Pollutants, but didn’t talk about it. This link is helpful for an overview: http://www.youtube.com/watch?v=qoYYbluZ8tw and these pictures should help you out:


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by derrickwillard

Green Week?! What?

You guys were out of school on April 22nd, so (BELATED) HAPPY EARTH DAY!

If you did notice lately, it is very “hip” to “green.” I’m watching my favorite NBC comedy shows, and seeing all these public service announcements for “green week.” Heck, even the NBC peacock logo is green this week! Check out NBC’s slick website: http://www.nbc.com/Green/

And, FOX is getting in on the act too. Sue got kicked off Glee, but she’s doing public service announcements?! Check out their slick website: http://www.fox.com/greenitmeanit/

This type of public relations stuff is called “greenwashing.” Here’s a definition (can’t find or recall the source):

Greenwashing is the unjustified appropriation of environmental virtue by a company, an industry, a government, a politician or even a non-government organization to create a pro-environmental image, sell a product or a policy, or to try and rehabilitate their standing with the public and decision makers after being embroiled in controversy.

So, why is what NBC or Fox doing this week considered sorta sly? Well…do you think the network executives are doing it for the network or us (or both)? You decide.

If you want to know more, here are a few “watchdog” sites that monitor greenwashing:







So, be a smart consumer, not all that is green is good. ANY group can claim to be green-there is no government standard! Love to discuss any of this with any of you here or in class one day…can you think of other examples you’ve seen?

Oh….here are some headlines about issues we have been studying…weird how reading/watching the news is studying for this exam:

Planet Ark: Fuel Rod Cooling Halted by Rates at Crippled Japanese Nuclear Plant

NPR News: Arkansas Oil Spill Sheds Light On Aging Pipeline System

USA Today: Invasive Pests Cost Americans Millions

Planet Ark: Dead pigs in China river spotlight heedless industry


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by jennacomisar
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2 questions for test

Hey guys,

I have 2 questions for tomorrow’s test.

1) I am confused with how oil sands are extracted and refined.

2) This was one of the questions on the review guide and maybe i just overlooked it in the text, but:

What issues are involved with mining and refining uranium (enrichment)?




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by derrickwillard

Energy Math

*Since I did not name a scribe so close to Prom, here is a guest post by ClayF from last year on energy conservation AND energy math problem types on the AP Exam…

For the first part of Monday’s class, we discussed various ways to conserve energy in our homes, in transportation, and in energy generation.

At home:

  • Energy Star Appliances
  • Check insulation/Fix leaks
  • Turn the thermostat up in the summer and down in the winter
  • Use power strips to reduce vampire load aka phantom load
  • BULB CHOICE-Even though many CFL (compact flourescent) bulbs may seem more expensive at the store, they actually save you more money in the long run.
  • We would like a high EROEI (Energy Returned on Energy Invested) value
For the second part of class, we discussed a number of ways to calculate energy problems.
The first equation is about energy and power:
We must remember that one watt is a very small unit, and it is much more common to see homes and factories using kilowatts or megawatts.
1W= watt 1KW=Kilowatt=1,000 watts 1MW=Megawatt=1,000,000 watts
The second equation is about heat transfer:
There are two different versions of this equation, the Metric version and the English (industry standard) version. They are the exact same equation, except for the units. We must also remember that the specific heat of water (the energy required to change the temperature of water by one degree celsius) is always 1. This is important because many home appliances and power plants heat water for various reasons.
The third equation is cost:
This is just a simple equation used to determine the total price paid for more than one product.
The fourth and final equation is efficiency:
This equation tells us how efficient a type of technology (light bulb, wind turbine, etc.) is. A higher level of efficiency is obviously the more desired amount.
Big W for the pictures
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