The pulley lab experiment was different than the other robotics lab experiment we did, even though it used some of the same Legos. One of the Lego pieces that look like a crank was attached to a pulley that had weights on it. We hooked up out little Lego robot to the computer and made the pulley move, which was much faster than what I was expecting. The first time we pressed go, we did not know that we had to stop the pulley by operating the Lego robot, and it almost got caught in the crank because we did not stop it. After we figured out how to work the robot and pulley, we had to do two separate test runs.

For the first portion of our test, we changed the weight/mass that the pulley had to lift each of the four times that we ran the experiment. We did increments of 20mg each try, and kept a consistent power of 60. The results for the power used was always in the .23-.29 range. The acceleration was always between 31.457 and 42.461.

The second portion of our test had a different power for each of the four tries, but we kept a consistent mass of 160mg.

 *You may need to click on this chart to see all of the number clearly! Sorry for the tiny photo!

Coal-Fired

Coal has been used as an electricity generator since the 1880’s, when the United States built the first power plants. Coal-fired power works by crushing pieces of coal into a fine powder, and then burning the powder. The burning coal gives off heat, which generates steam that makes the turbines spin and generate electricity. When the coal powder is quite fine, it will burn almost as efficiently as a gas would.

Natural Gas

Plants and animals store energy from the sun, and after thousands of years of pressure, natural gases are created. The stored energy is what essentially creates the natural gas, after it is exposed to intense heat. The stored energy from natural gases is combusted into electricity generation, which makes it a usable power source.

Nuclear Power Plants

Fission caused by uranium atoms splitting gives off heat, and that is the heat source for nuclear power plants as an electric generator. Steam from water mixed with the heat from fission is what makes turbine generators produce electricity. There are two types of nuclear power, one where the water used in the source does not boil because of pressurized water reactors. The second type is boiling water reactors.

What are the differences?

Well, to start off, boiling water reactors used in nuclear power plants can be used again and agin because of the steam and the process of evaporation/condensation. On the other hand, the electricity from natural gases is a nonrenewable source because it takes so long (over thousands of year) for these gases to be produced. With coal-fired power, many people are worried about the negative effects it may have on the environment, such as releasing toxic chemicals, and carbon dioxide emissions. However, many experts believe that the benefits of coal are greater than the negative impacts it may have, thus still being one of the best sources for electricity generation.

References:

http://www.rst2.edu/ties/acidrain/iecoal/how.htm

http://www.epa.gov/cleanenergy/energy-and-you/affect/natural-gas.html

http://www.duke-energy.com/about-energy/generating-electricity/nuclear-how.asp

September 16th, 2014

Lego Robotics Activity

The Lego robotics activity was very interesting to me. I was mesmerized by the fact that I could build a moving robot out of some Legos and a battery pack. I was a bit confused when we began the activity because it was difficult for me to realize the difference between the different pieces (i.e. the short black sticks that looked similar, but were not the same). After my partner and I figured out the pieces, we finally built it, with only a few little mistakes. Once our robot was up and running and we plugged in the USB cord to the computer, I was amazed! The fact that changing the numbers on the computer would make our robot move faster or slower, for longer or shorter, was unlike any experiment I have done before. I enjoyed changing the time and speed of the robot, because we never knew what the outcome was going to be.

Measuring the robot’s travel with a ruler was slightly different than when the computer measured the robot’s distance. There were only two instances out of nine separate tries that we got the same exact number on the ruler as the number that was on the computer. For our first trial, we set the speed to 38 and made it travel for 2 seconds. The distance on each try varied, and we got 28 centimeters for the first try with the ruler, whereas the computer calculated that it went 28.3 centimeters. On the second try we measured 27.8 centimeters with the ruler, and the computer measured 27.75 centimeters. The final try resulted in 28.1 centimeters with the ruler and 28.15 centimeters with the computer.

On the second trial, my partner and I decided on setting the robot to travel 1.5 seconds at a speed of 42. We had 23.6 centimeters on the ruler for the first try, and 23.3 centimeters on the computer. For our second try, both the ruler and the computer miraculously measured out to be 23.3 centimeters. On our last try for trial three, we measured 23.4 centimeters whereas the computer measured 23.25 centimeters traveled.

The third and final trial had a speed of 60 and 1.2 seconds to travel. We measured 27.4 centimeters for the first try, and the computer measured 27.5 centimeters. On our second try, we measured 27.3 centimeters with the ruler, and the computer measured 27.25 centimeters traveled. On our last try, we once again measured the same distance traveled as the computer at 27.3 centimeters.

Although we were correct two out of the nine tries when measuring the robot’s distance traveled, there was still a percentage of error. I believe this is because the computer had a more precise measurement of the distance traveled, opposed to ourselves who were making the best judgements that we could when measuring. The percent error part confused me a little bit, for the fact that I have always had a more difficult time with math calculations. Our first trial had -1.06% error, the second trial had -.3642% error, and our final trial had .1833% error. This resulted in an overall total of -1.809% error for our experiment.

What is fracking?: 

Fracking is a nick-name for hydraulic fracturing. Hydraulic fracturing “is the process of extracting natural gas from shale rock layers deep within the earth” (what-is-fracking.com). This is basically being able to obtain natural gases from shale plays that were not reachable before. Shale plays are places where companies actively search for natural gases and oils to use. People are able to reach these gases and oils by drilling underground into the rock layer and pumping in water, mixed with sand and chemicals. The water is blasted into the deep rock at a high pressure, and by putting in the water mixture, the rock layer forms cracks that release the gases into wells. The gases released into wells give companies more gas/oil to use. Hydraulic fracturing has taken place in the United States in Texas, Pennsylvania, New York, Colorado, among a few others. Internationally, fracking has taken place in Northern England.

Pros:

One major benefit is that fracking creates new passages to allow more gases and oils to flood out of the wells, many of which were unobtainable before. Other than faster flood of gases and oils, there are not many more pros to fracking.

Cons:

One con which I found interesting is that communities where the fracking is taking place are experiencing an increase in criminal activity, decreasing property values, and loss of tourism. Another major con is the use of potentially dangerous chemicals. Although companies are not saying which specific chemicals they are using, traces of carcinogens and endocrine disruptors have been found. These two chemicals are extremely harmful, for the fact that they can lead to cancer in many cases.

Environmental Impact:

Many people that are pro-environment are angry about the use of fracking and want to ban it, for it has such a negative impact on the environment. It is impacting the environment around where the drilling takes place because people that live nearby are becoming extremely sick from drinking contaminated water, caused by the fracking. Another impact it has is that it is contributing to the climate change due to the leakage of methane, which is a greenhouse gas. Environmentalists are also angry because fracking requires large quantities of water, which is the water that becomes contaminated and makes people sick. The process of fracking has lead researchers to believe that it is causing small tremors/earthquakes. One example of an earthquake caused by fracking is in Blackpool in 2011, where two earthquakes were recorded.

References: 

http://www.bbc.com/news/uk-14432401

http://www.what-is-fracking.com/what-is-hydraulic-fracturing/

http://www.foodandwaterwatch.org/water/fracking/

http://earthjustice.org/features/campaigns/fracking-across-the-united-states

The nation’s energy grid is called the power distribution grid, which starts at the power plant and typically consists of spinning electrical generators. There are different ways to spin the generators (diesel engine, gas turbine or hydroelectric dam) but the most common one is the steam turbine. Commercial electric generators will generate 3-phase AC (alternating current) power, which are offset 120 degrees form each other. The 3-phase power then enters a transmission substation that uses large transformers to convert the voltage to be extremely high for long distance transmissions. Every power line has three wires for each of the three phases, along with regulator banks (which could also be underground) to prevent under voltage and over voltage. The wires are attached to the poles in front of houses, and every pole has a transformer drum. The wires connect to the houses, and gives a certain voltage of power that creates electricity for the household.

The smart grid is different from the typical energy grid, since it uses automation and computer based remote controls. The smart grid allows people to see how many watts they are using whenever they use their appliances, rather than waiting for the electric bill. This allows people to realize when they should or should not be using excessive power to keep the cost down. Basically, the smart grid lets people communicate with their technology by the sensing along transmission lines.

Pros: There are many pros to the smart grids, one major one being that they minimize power outages. The smart grid can detect where the power outage is before it becomes a larger problem. Another benefit is increased security and more efficient transmission of energy. It will benefit electric companies by getting rid of manually reading meters. The smart meters will also decrease greenhouse gases from existing power plants.

Cons: Some of the cons include managing long-term financial commitment towards producing the smart grids, and customers will have to pay extra fees. They will also need verification that the grids are accurate and will protect everyone’s personal privacy. An environmental concern is the disposal of the old metes.

References:

http://science.howstuffworks.com/environmental/green-science/smart-grid4.htm

http://science.howstuffworks.com/environmental/energy/power.htm

http://energy.gov/oe/services/technology-development/smart-grid

https://www.smartgrid.gov/the_smart_grid

http://energy.about.com/od/metering/a/Pros-And-Cons-Of-Smart-Meters.htm