PDS AP Environmental Science 5th Period 2011-12

*Since we are out of scribes, here is a guest post by ClayF in the other class…

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 bulbs may seem more expensive at the store, they actually save you more money in the long run.

• CAFE Standards to increase fuel efficiency

Generation:

• 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.

*CLICK ON THE PICS TO ENLARGE*

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.

This photo is a collection of histograms, or population pyramids, created by students in our class.  The graphs have been specifically placed in different stages due to their respective locations because of their population characteristics.  The majority of the countries in stage 2 are developing countries with very high birth rate and low death rates; therefore, they have larger bases of their pyramid which also leads to population momentum (there is such a high concentration of people that will soon be able to reproduce) .  The specifics of each stage are stated in the previous post.  An observation that can be made is that the bases decrease in size as the stage increases.  Also, as stage increases, the total fertility rate decreases, the life expectancy increases, and the infant mortality rate decreases.

Due to vertical analysis, we can split a histogram into three sections.  The first section is the pre-reproductive category (Ages 0-14).  Next is the reproductive category (Ages 15-45).  This is the only stage where women are reproductive and can add to the population.  The last section is the post-reproductive category (Ages 45+) where woman are no longer able to reproduce.

Abnormal shapes in the graphs may be caused by a variety of things such as war, disease, mass migration, family planning programs, and even economic recessions (the cost of children is too expensive-birth rates decline).

This video somewhat explains different types of pyramidal shapes.

Population Pyramids

Today in class we talked about the “way of knowing” something about any topic by conducting good experimental design.  There are two different types of experiments: natural experiments and controlled experiments.  A natural experiment is based off of observations.  Studying the trends of consumer purchases of cigarettes before and after news that cigarettes cause lung cancer is an example of a natural experiment.  A controlled experiment is manipulative, meaning the person conducting the experiment chooses which type of factors are in play.  We are conducting a controlled experiment in class by studying the effect that increasing concentrations of salt have on the ability for radish seeds to germinate.  We will follow this outline as we test our experiment: Also, remember the four rules that make up a good experimental design.  First, make sure you have a large sample size to work with.  Second, make sure to do many repetitions.  Third and Fourth, make sure that you have high accuracy and high precision.  To help you understand accuracy and precision a little easier, use this diagram.

Sources:

http://www.renaissanceexercise.com/do-or-do-not-there-is-no-try/

http://wps.prenhall.com/wps/media/objects/3310/3390101/blb0105.html

The biggest problem pertaining to the environment that we face today would have to be air pollution.  With all of the automobile exhaust all over the world and factories emitting noxious gasses into the atmosphere, air pollution is definitely the largest environmental problem.  Many cars or motorcycles around the world don’t use catalytic converters to breakdown dangerous gasses which cause damage to the air.  Also, factories disobey regulations that would otherwise protect the atmosphere, so this is why air pollution is so prevalent today.