PDS AP Environmental Science 8th Period 2011-12

This article shows the future of solar energy in Africa by providing cleaner and more accessible energy to the impoverished communities.
The article mentions that the only current source of energy and heat is burning wood and coal which can cause tuberculosis and asthma. The transition utilizes solar powered hot water heaters and clean-burning cooking stoves which are types of active solar energy. This is a unique example of how solar energy can improve the health of less fortunate societies through Active Solar Energy. The other main method of solar energy is Passive Solar Heating. The major difference between the two types of solar energy is that passive solar heating doesn’t require the use of mechanical and electrical devices like active solar energy does.

Passive Solar Heating is used to collect, store, and distribute solar energy in the form of heat in the winter while also to reject solar heat in the summer. This technique takes advantage of the building design, but the designing must be done during the construction of the house or building. Examples of the building designs are things like positioning windows on the south-facing walls to let sunlight and heat in, covering roofs with dark material to maximize heat absorption, and having overhangs to block sunlight in the winter.

Here is a visual to passive solar heating:

This is a video that better explains how window positioning helps passive solar heating.

*While you don’t have to spend extra money on equipment, construction costs can run high but usually pay themselves off within a few years.

Active Solar Energy is used to convert solar energy into a more useful form of energy, such as heat or electrical energy. Examples of active solar energy are things like a small scale water heating system, photovoltaic solar cells, and large concentrating solar thermal systems. Water Heating Systems can be used for household water, public swimming pools, or businesses and is generally driven by a pump that is powered by the sun. A Photovoltaic Solar Cell is an electrical device that converts the energy of light directly into electricity. Many of the solar cells are paired together to make the solar panels that are seen on houses and buildings. Concentrating Solar Thermal Systems use mirrors or lenses to concentrate a large area of sunlight, aka solar thermal energy, onto a small area which then converts the light to heat. This drives the turbine that is responsible for generating the power.

*Active solar energy can generate hot water or electricity without polluting the air or water as it doesn’t produce CO2, but the installation of these technologies can be expensive.

Tags: energy, renewables, solar

Does anyone know what US legislation/agencies we need to know? Also, on the study guide Mr. Willard mentions something about the efficiency of feed to meat conversion, can anyone explain what the answer might be to that?

Today in class 2/21, we began the next unit on food production and soils. We began class by looking at The Hungry Planet: What the World Eats and comparing pictures of what families (around 5 people) ate over a week period. We compared what the families ate and the US dollars that would be spent on each week — for a typical family from Chad the costs was about $1.23 and for a typical American family the costs was about $350. We then related that information the the demographic transition — the wealthier a country is the more money they can spend on food and other items that might not be as necessary, things like processed foods and soda.  Here are two links to the pictures that we looked at in class:

http://www.time.com/time/photogallery/0,29307,1626519,00.html

http://www.time.com/time/photogallery/0,29307,1645016,00.html

For additional reading, here is a link to a New York Times article that may help those of you who missed class. This article talks about new research that can explain better approaches to dieting and how to curb your appetite.

http://www.time.com/time/specials/2007/article/0,28804,1626795_1627112_1626671,00.html

After the introduction, we began talking about Food Systems. The earth is made up of 25% land and 75% water. Of that land, we use about 38%  of that for food production which is responsible for 93% of the calories that we take in from things like croplands for crops and rangelands for meats. The water on the other hand is responsible for 7% of the calories that we take in from things like fisheries and aquaculture.

For the more visual individuals, here is a picture of Mr. Willard’s organized notes:

After the introduction to Food Systems, we covered Farming. The two types of farming that we talked about were Industrialized and Traditional.

Industrialized Farming (aka conventional farming)

• makes up about 80% of farming
• has a high input of resources
• high crop yield, meaning the land is very productive
• typically monoculture, meaning only one type of crop is grown and harvested
• Also has very many negative environmental impacts (which we will cover later)

Traditional Farming (aka subsistence farming )

• makes up about 20% of farming
• typically polyculture, meaning a variety of crops are grown and harvested
• used by individuals who typically produce just enough for their family to get by

Again, here is a picture of the organized notes:

Tags: agriculture

I missed friday, so I am still a little confused with the ecoindustrial revolution.  I read the scribe post and watched the short film. I got that the goal is cradle to cradle and that two more R’s were incorporated but I’m still confused on this topic.  Is it the two extra R’s that make it cradle to cradle? If someone could clarify/explain in a simpler way that would be awesome, thanks!

In class, it was said that if a toxin is able to be dissolved  in oil then it will persist in the fat of the organism which then leads to bioaccumulation/magnification. So does this mean that if a toxin is water soluble that it will never bioaccumulate?

The students at PDS, with the help of their teacher, started this blog in order to help out everyone interested in or taking a class on environmental science. Having a class blog is something that not only benefits the students who “run” it, but also helps out around the world for curious individuals seeking some extra help about Environmental Science.

Overall, this blog is a very handy tool as it is a place that you can ask questions, summarize a day’s notes for students who have missed class, and/or post any interesting issue or events that pertain to environmental science – one student described it as interactive inquisition!  Having this tool available online also assists the teacher when it comes to test preparation. The day before test, students always have some issue that need a little more clarification.  So to reduce the amount of repeated questions that one teacher must answer, having one shared blog between the class allows for the question of one to help others. A student agrees as she stated that the posts before tests are really helpful because sometime people ask questions that she didn’t realize she also didn’t know the answer to. Another perk of the online tool is it keeps things organized with categories and tags as well as our class syllabus and websites that are helpful tools.  Additionally, having this blog open to the public allows individuals from all over the world to ability to comment on post left by students. They can challenge or agree with the posts, but this opportunity helps keep an open minds about some topics.

When asking fellow students to say something they didn’t like about the blog, it was hard to find any critiques. It seemed as though everyone loved the blog! Although it has its upsides, it also may not be for everyone. Having this blog makes all classwork and notes more internet based which some people may not like. Some students would rather have handouts and come in for help from the teachers themselves rather than reading the lesson online from someone else’s perspective.  One thing I do not like about the blog is that it allows for a lot of bias when asked to post what is relevant about that days notes. But other than that, the blog has served everyone well this past semester!

I have three categories under land management: multiple-use land, moderately restricted-use land, and restricted-use land. The examples I have for multiple-use land are national forest systems and national resource lands (range lands). I was just wondering if this category is the same thing as mixed land use like the first principle of smart growth? Or are they different things with just similar names? If they are different could someone explain how so? Thanks!

I was reviewing the Unit 2 test on chapter 3, and I have a question about the answer to number 6. The question asks : Carpenter ants, termites, earthworms, and beetles are all examples of either carnivores, detritivores, decomposers, scavengers, or primary producers. The correct answer is B: detritivores and I was confused because I’m pretty sure/it says on our handout that earthworms are decomposers. So I guess my question is what is an earthworm’s niche, and is it possible to be a detritivore and a decomposer?

Also, with the demographic transition, the book categorizes Stage 4 as having a declining population. Is that always the case for stage 4 countries?

In class the other day, Mr Willard said something about the demographic trap which is when a country moves backwards on the demographic transition model. I am kind of confused on what that means and how that happens.  Is it the same thing as negative growth or am I on the wrong page? If someone can clarify that would be awesome, thanks!

I was looking over the Chapter 5 study guide and question 5 is confusing me. I have the diagram but I was wondering if someone could explain the diagram and the idea about phylogenis and phylogenetic trees in more detail than the book did? Also, question 16 asks about realized and fundamental niches. Do organisms live in fundamental niches or are these just for a comparison to what the organisms ideal environment would be? Thanks!