The Science Behind Batteries

Considering how widespread batteries are, it is surprising how little the average user knows about them. Batteries power many wireless electronic devices around the world. There are two general categories of batteries, disposable, or dry cell, and rechargeable. All batteries store electrical energy in chemical form. A cell is the working chemical unit within the battery. Disposable batteries use primary cells, while rechargeable batteries use secondary cells. Some batteries have more than one cell. There are three components in all cells, the positive electrode, the negative electrode, and the electrolyte. The electrolyte is either a liquid or a dry powder. The positive and negative electrodes are also known as the cathode and anode respectively. Figure 1 shows a primary cell.

Figure 1.

howbatteryworks

Electricity is the flow of electrons through a wire or any conductive path. Batteries produce electricity through multiple chemical reactions. The types of reactions depend on the type of battery. There are many varieties of batteries that contain different materials in their electrolytes and electrodes. Some examples of disposable batteries with primary cells include zinc-chloride, alkaline, and button. No matter the specific reaction, all the reactions achieve the same goal of moving ions. In a primary cell, the chemical reactions generate positive and negative ions. As you can see in figure 1, the positive ions move through the electrolyte towards the positive electrode. At the same time, the negative ions, or electrons, flow around the outside circuit. Primary cells cannot be used again because as they generate energy, they convert the original chemicals into different chemicals. Once the cell runs out of reactants, it can no longer generate electricity. Below, Figure 2 shows a secondary cell.

Figure 2.

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In figure 2 you will see pink circles and arrows. Those represent the movement of electrons in the small circuit with a light bulb. This small circuit demonstrates the flow of electricity. Without the connection to the light bulb, the flow of ions does not occur. The chemical reactions within the battery cause a build up of electrons in the anode. When the battery is not being used, the electrons become very tightly packed. Electrons repel each other. They would like to go to a place with fewer electrons, like the cathode, but the only way they can do that is through some sort of outside circuit. When the electrons have the opportunity, they will move away from the anode, through the circuit to the cathode. This kind of battery is used in cellphones, computers, and cars. Running a current through them in the opposite direction recharges it. By running it in reverse, the chemical reactions are also reset. Some examples of rechargeable secondary cell batteries include nickel cadmium (NiCd), nickel metal hydride (NiMH), and lithium ion batteries. A lithium ion battery is the kind that is most commonly used in cell phones and computers.  

Figure 3.

energizer-recharge-value-1

It is great what batteries enable us to do. Without batteries, we would not be able to enjoy the convenience of wireless phones, laptops and much more. However, they do take a toll on the environment. There are pros and cons to using either type of battery. For a while it was better to use disposable batteries because even though more of them went to the landfill, the chemicals in them were much less harmful than the chemicals in the rechargeable ones. However, since the creation of the nickel metal hydride battery and the advancement of the lithium ion batteries, it has become increasingly beneficial to use rechargeable batteries. Next time you are changing the batteries in your flashlight, consider using rechargeable batteries. It will not only be better for the environment, but it will also save you money!

References:

http://www.greenlivingtips.com/articles/disposable-vs-rechargeable-batteries.html

http://www.qrg.northwestern.edu/projects/vss/docs/power/2-how-do-batteries-work.html

http://www.explainthatstuff.com/batteries.html

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Keystone XL Pipeline: Environment Versus Economy

There are always two sides to a story. Sometimes there is more than two, but today I am going to focus on the two main sides of the Keystone XL Pipeline story. The story of the Keystone Pipeline is enormous with many opinions and arguments. For those who do not know already, the Keystone Pipeline runs from Alberta, Canada to Cushing, Oklahoma. However, there have been plans to expand the pipeline for a long time. The 1,700 new miles of the pipeline would represent two new sections, a southern leg and a northern leg. This larger pipeline is referred to as the Keystone XL Pipeline. Not everyone agrees that this expansion is a smart idea. There are large concerns for the possible environmental effects of this new pipeline and the kind of oil it would be transporting. However, those who are in support of the pipeline believe that it would help the economy tremendously. Here is a map showing The Keystone Pipeline and the Keystone XL Pipeline. The dotted lines are the XL sections.

Keystone-Map

The biggest environmental concern is the use of heavy Canadian tar sands oil. The existing pipeline carries U.S. light crude. The difference between these two types of oil is dramatic. If the Keystone XL Pipeline was built, the pipeline would be able to deliver 830,000 barrels of oil per day. Unlike U.S. light crude, tar sands oil, or bitumen, has a large amount of clay and sand in it. It is also more corrosive than conventional oil. So, not only is this corrosive oil more likely to cause leaks in the pipeline, but it would also cause more damage when spilled. The heaviness of the oil causes it to sink into the earth and water rather than floating on top of it. Also, before tar sands oil can be used it has to be refined into usable oil. This process uses tons of water, which is already a dwindling resource. In addition, tar sands oil releases more harmful emissions into the atmosphere than other oils when burned. A Final Supplemental Environmental Impact Statement for the XL pipeline found that the pipeline would not have a significant impact on climate change as a result of tar sands oil because it will be extracted whether or not the pipeline existed. I partially disagree with this statement because, yes the extraction will continue without the pipeline, but with it the use of tar sands oil will only grow. Without the pipeline, people are either forced to find a different source of oil or a different source of energy. Yet, if they are given tar sands oil they will most definitely use it.

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Considering how much concern exists surrounding the new pipeline, there are a lot of people who support it and think it is a great idea. The main benefit that people feel most strongly about is the benefit to the economy. It is estimated to create anywhere from 40,000 to 20,000 jobs in the U.S. It will also allow the U.S. to reduce its dependence on foreign oil. Currently, President Obama has 10 days to veto the bill authorizing construction of the Keystone XL. Both the House and the Senate passed the proposal. However there was not a wide enough margin to override a presidential veto. Shortly we will see if the Keystone XL Pipeline will be built.

Sources:

http://stateimpact.npr.org/texas/tag/keystone-xl-pipeline/

http://www.cnn.com/2015/02/11/politics/boehner-obama-keystone-veto/

HomeKit: The Future of Household Energy Use

There are issues with all of the aspects of energy, the creation of it, the uses of it, and the cost. Finding alternative renewable energy sources or inventing new technologies would help solve these problems, but it takes a long time and there is no guarantee that they will become widespread. Another way to improve the energy situation is to decrease the amount of energy being consumed. Decreasing the amount of energy that people everywhere use may seem like an incredibly difficult goal, but if anyone can create widespread change it is Apple. imgres

logok.org

With its enormous influence in the world of technology and impressive amount of brand loyalty, Apple has the potential to make a lot of positive change. However, energy saving is not necessarily what Apple is known for. In fact, it has played a large part in the rise of energy consumption with the creation of the iPhone and other popular electronic devices. Nevertheless, Apple’s next product might help bring energy consumption back down. The new system is called HomeKit.

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https://developer.apple.com/homekit/

HomeKit will be a new feature of IOS. It is designed to allow smartphones to control various accessories in one’s home. It will allow one to remotely control lights, thermostat and much more. Users can interact with Siri, an intelligent personal assistant included in most iPhones, to control their HomeKit. The HomeKit will be a common database that will communicate with all of the various accessories in the home. There will undoubtedly be a rise in new products that can be controlled wirelessly and then can connect to the HomeKit. There is no limit to what the HomeKit can control as long as the accessories have wireless capabilities.

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blog.azoft.com

The software is designed to be as user friendly as possible. For example, the user can name lights in their house, so they can simply tell Siri to, “turn the kitchen lights on,” and HomeKit will know which lights to turn on. This system will not only change day-to-day life for millions of people, but it also might help form energy efficient habits. Enabling people to perform these small tasks without having to physically move will make saving energy more convenient and attractive. It also allows users to control their home when they are not even in the home, therefore allowing them to conserve energy on heat and AC when the house is empty. Home automation can make it easier for users to be more energy conscious. This will in turn create a more energy efficient society.

References:

https://developer.apple.com/homekit/

http://news.nationalgeographic.com/news/energy/2014/12/141231-2014-cool-energy-ideas/

Offshore Wind Farms and Undersea Power Cables

Energy use causes problems far and wide, making the search for a solution difficult. While the search for alternative forms of energy continues to be an issue, the new phenomena of offshore wind farms and use of undersea power cables together are proving to be a potential resolution to this persistent problem. A wind farm is made up of many wind turbines. When wind flows through the blades of the turbine, they start to spin. The blades of the turbine are attached to a drive shaft, that when spun causes an electric generator to turn and produce electricity. [1]

images

www.telegraph.co.uk

Offshore farms are superior to land wind farms for a variety of reasons, not all of which are scientific. Wind turbines take up a lot of land and many people find the wind farms to be unattractive and do not wish to see them near their homes. Second, winds tend to be faster and more consistent offshore rather than on land. According to the Bureau of Ocean Energy Management, “a turbine at a site with an average wind speed of 16 mph would produce 50% more electricity than at a site with the same turbine and average wind speeds of 14 mph.”

An offshore wind farm in Germany consisting of 80 turbines generates enough energy for 400,000 homes. [2] The power generated travels through cables 6.5 feet under the ocean floor. These cables were originally used as submarine power cables. They are also being used to connect one country’s power source to another’s. One example is the 360-mile long cable connecting Dutch and Norwegian power sources, called the NorNed. This connection allows the Dutch to use hydroelectric power generated by Norway during the peak of demand for energy during the day and the Norwegians are able to use the energy from Dutch power plants as needed as well. Amazingly, this linkage reduces CO2 emissions by nearly 1.7 million tons per year. [2] Many countries are intrigued by this idea and plan on making connections of their own. Scotland, for example, is planning on building a line to England. It is an ambitious plan to build a $1.1 billion, 239-mile cable under the Irish Sea. Many other countries are getting involved with similar projects as well such as Canada, the U.S. and many others.

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Above: Engineers work on building an undersea cable [2]

The construction of these lines is very expensive because not many places make these undersea cables and the ships that are built for “cable-laying” are also in short supply. However, with the growing interest and value of these cables, the market for this product is predicted to grow much larger in the coming years. The use of offshore wind farms is also increasing. Since it solves the problems of land use and efficiency, these farms will undoubtedly become more common and increasingly more advanced. Offshore wind farm projects are being planned in Denmark, the United Kingdom, Norway, the Netherlands, Japan, China, South Korea, Belgium, Sweden, Italy, Portugal, and others. [1]

Save the otters!

Sea otters live along the coasts of the Pacific Ocean in North America and Asia. Ever since their population plunged in the early 1900s, sea otters have been in danger of extinction. It would be especially devastating for sea otters to go extinct because they are a keystone species. National Geographic defines a key stone specie as, “a plant or animal that plays a unique and crucial role in the way an ecosystem functions.” (1)

Figure 1.

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As you can see in Figure 1, sea otter populations reached a low in the early 1900s. As a result of the fur trade, sea otters were almost hunted into extinction.(3) Sea otters populations once numbered several hundred thousand. So even though this graph shows growth, the population now, a mere 2,000, is nowhere near where it once was.

Figure 2.

kelp-bed1

http://www.eoearth.org/view/article/156656/

The reason sea otters are considered to be a keystone species is because of the role they play in their food web. In the figure 2, kelp and other algae serve as primary producers. This means that they are autotrophs and are able to make their own food through photosynthesis. The next trophic level includes sea urchins. They are known as primary consumers because they get their energy from consuming the primary producers. From there, sea otters would be secondary consumers because they eat the sea urchins. When this system works, each level keeps the level below them from overpopulating. However, when one species within the web experiences a decline in population, it affects the entire system. In the case of the sea otter, they are considered the most important, keystone species because they keep the urchin population controlled.

In 1900, when the otters dwindled in numbers, the sea urchin population exploded. This caused the urchins to consume so much kelp that they destroyed the kelp forest.(2) This is an example of a trophic cascade. A trophic cascade happens when population control of prey by their predators affects the next level down, in the case, kelp.(2) This ecosystem needs the otters to prevent another trophic cascade. If the otter population continues to grow, this fragile ecosystem will be restored.

images

montereybayaquarium.org

Sources:

1. http://education.nationalgeographic.com/education/encyclopedia/keystone-species/?ar_a=1

2. http://www.eoearth.org/view/article/156656/

3. http://www.defenders.org/sea-otter/threats

Iran’s Demographic Transition Gone Wrong

According to the theory of demographic transition, Iran is currently in stage four. This is proven by their decreased birth rate, improved medical care and urbanization. However, they are not pleased with stage four. Iran’s supreme leader Ayatollah Ali Khamenei was especially concerned by how the economy might suffer. Therefore, Mr. Khamenei is making it illegal to have permanent birth control procedures such as vasectomies and tubectomies, in an effort to increase birth rates. Although these methods may seem dramatic, there is still little to no increase in population. No matter how hard Iran may try, going against a demographic transition is harder than it may seem. This is because of the population momentum created in earlier generations.

Figure 1.

2

As you can see in Figure 1, Iran began stage 1 of their demographic transition in 1960, where there was some population growth. Around 1985, they were at the peak of their growth, stage 2 or 3. This dramatic increase can be explained by the typical decrease in death rates as a result of improved medical care as the country becomes more developed. This coupled with continued high birth rates creates an increase in population commonly know as a population explosion. The transition from stage 3 to stage 4 was very abrupt. The steep decline in population growth was caused by urbanization, increased education of women and use of contraceptives, which lowered the birth rates. Iran’s transition from stage 3 to 4 was particularly significant because of the intense efforts at the time to decrease birth rates. This was achieved through promoting the use of contraceptives and increased propaganda to encourage couples to have less children.

 Screen Shot 2013-11-24 at 6.10.14 PM

Figure 2.

Figure 2 displays just what Iranian leaders are afraid of. As you can see in this 2013 age structure diagram of Iran, the decline in birth rates has created a smaller generation of young people. If this trend continues, the working class will shrink and the economy will suffer. This decline in birth rates is a proven trend among other countries at stage 4. Once education improves, people become more interested in their careers. This causes many couples to become less interested in having many children. This is exactly what is happening in Iran. However, the government is making an effort to reverse the trend. They are not only using propaganda and giving incentives to couples that have more children, but they are also passing laws against permanent contraceptives. By both discouraging the use of contraceptives and making permanent birth control procedures illegal, Iran has gone too far. They should not have the right to pass a law against these procedures.

Not only is Iran wrong about this law, they are also wrong to even try to increase population growth at this stage. There is a reason that growth rate has slow down. In stage 4 of the demographic transition, it is common for families to have around two children because it is has become more expensive to raise children. Couples would rather focus on giving the best possible education and resources to their two children rather than struggle with 3+ kids. Even the incentives that Iran is using are not working because couples are confident and clear on their decision to have fewer children. Trying to fight the process of demographic transition is not a good way to solve economic problems. It might even make it worse. Although the economy will suffer if the trend continues, Iran must find another way to avoid their problems because this solution will clearly fail.

References:

http://www.telegraph.co.uk/news/worldnews/middleeast/iran/10554866/Iran-attempts-to-reverse-falling-birth-rate.html

http://www.economist.com/news/middle-east-and-africa/21603477-irans-leaders-are-worried-about-their-countrys-declining-population-make-more

https://cac-ib-geography.wikispaces.com/Iran

http://viableopposition.blogspot.com/2013/11/irans-demographic-crisis.html