This week in class we focused on fine tuning our plan. After some conversation and jokes we decided on going with the classical collision between toy cars on a track.
Tools:
-2 Toy cars
-1 vertical track
– Sensors to record the velocity
-nxt software and computer
What we are going to do:
We are going to have two motion sensors on both ends of the track. One of the toy cars will be at a standstill at the middle of the track. We will weigh the cars because we need the mass along with the velocity of the carts to calculate the momentum (remember p = mv). We will push one car (on the far side of the track) into the car at the middle of the track. The motion sensors will track the movement of the cars on either sides and record them into the computer. With the recorded velocities we will calculate the momentum. We will run 5 trials.
Our group consisted of me, Anestis, Nurta, Cris, and Ramon
After debating for a bit about what we should do for the experiment we decided we wanted to do an experiment including collisions and explosions. After the professor told us that we couldn’t make a hydrogen bomb because it was too dangerous we decided to make two objects collide and explain the interactions within the two objects. We thought about what actually happens when things collide other than destruction and explosions and realized that the conservation of momentum pretty much summed up everything we were trying to show. The conservation of momentum states that For a collision occurring between 2 objects, the total momentum of the two objects before the collision is equal to the total momentum of the two objects after the collision. Therefore the momentum lost from object 1 is equal to the momentum gained by object 2.
So we decided to collide two objects and record the momentum’s of both objects and prove that the conservation of momentum is valid. We still haven’t worked out all of the details yet but I will post our plan in the next blog!
This week in Energy & Sustainability class we held an experiment to see how generators functions with turbines to produce electricity. We gathered some instruments that would help us find out the relationship in generators and turbines. Experiment: For our experiment we had a flashlight that didn’t operate on batteries. It had a coil of wire in the middle of the flashlight and an metal object would produce voltage when it was passed through the the coil of wire. To create electricity all one need to do was to shake the flashlight. After shaking the flashlight for a while we turned the light on it was bright, after a while the light dimmed and finally went out. We hypothesized that the more times the flashlight was shaken the more voltage that will be produced and the brighter the light will be. We hooked the flashlight up to the computer and it recorded how voltage was created when we shook the flashlight. We ran 3 different tests. Test 1: Shake the flashlight 60 times in 30 seconds (2 shakes every second) Test 2: Shake the flashlight 45 times in 30 seconds (1 and a half shake every second) Test 3: Shake the flashlight 30 times in 30 seconds (1 shake every second) Test 4: Shake the flashlight 15 times in 30 seconds (half a shake per second) After doing all these tests the excel file provided us with the data that we put on the table below.
Analyzing the Data:
The table shows what we got from shaking the flashlight for a specific amount of times. You may notice that there are a lot of negative numbers in the data but it doesn’t matter negative numbers only tell you what direction the voltage was flowing in. I simply ignored the negative signs and added them up for the total voltage produced.
Summing it all up we too the total voltages produced and placed them on another table according to the number of shakes. (shown below)
Using the table we made in excel we turned it into a graph to see if there were patterns and relationships between the voltage produced and the number of shakes. (shown below)
Looking at the graph we can tell that the relationship is definitely not linear. It looks more like an exponential relationship. In conclusion at the end we proved our theory right: that the more times we shake it the more voltage gets produced and the brighter the flashlight is. The graph proves the theory correct. Good job team!
Staying inside and doing experiments all the time is quite boring. This week in our Energy Sustainability class we went to MIT to see an actual Nuclear Reactor!
For those who do not know what nuclear reactors are. A nuclear reactor is a system that contains and controls sustained nuclear chain reactions. Reactors generate electricity, move aircraft carriers and submarines, produce medical isotopes for imaging and cancer treatment, and for conduct research.
When we arrived we had to go inside of a air sealing tunnel and then into the actually building where the nuclear reactor was. The nuclear reactor was encased in a blue dome which was a precaution if the nuclear reactor gave any problems. The walls were thick so probably none of the nuclear waste could reach the outside and possibly contaminate something.
MIT NUCLEAR REACTOR:
As explained to us when the group arrived at the MIT nuclear reactor location, the reactor was just a small reactor compared to most of the reactors in the world. The name of the MIT nuclear reactor is MITR-II and it is a tank type reactor. That means it has two tanks. One of the tanks for light water coolant moderator and the other one for heavy water reflector.
“The fuel elements of uranium are positioned in a hexagonal core structure, 38 cm (15 inches) across, at the bottom of the core tank. Power is controlled by six shim blades and an automatic regulating rod. The pressure in the system is practically atmospheric, and the maximum temperature approximately 50 C (120 F). An exterior shield of dense concrete makes it possible for research workers and students to conduct experiments and training without radiation hazards.” – http://web.mit.edu/nrl/www/reactor/reactor.htm
MITR-II fuel is fifteen fuel plates in a rhomboid-shaped element. Each fuel plate has fuel sandwiched between sides of aluminum cladding. The cladding is also finned to increase the heat transfer surface area. The uranium fuel is in a uranium-aluminum matrix called cermet.
The reactor is refueled about 3-4 times a year. It depends on how much the reactor has been used. Refueling can mean replacing two or three fuel elements with more fuel or a complete rearrangement of the core. The waste is picked up by the company supplying the fuel.
The group also visited the control room. It was basically a room where someone had to work and it told you if anything was wrong with the reactor by making noises. Little panels that lit up told which part of the reactor was the problem. Leaving the reactor every0ne had to be scanned by a machine to make sure no one had nuclear stuff on their clothes. The tour guide told us that if we did it wouldn’t be a huge deal we’d just have to wash our hands or shoes thoroughly.
Overall, it was a fun trip. I feel like I learned much more about nuclear reactors and their uses. I hope I provided a decent explanation of our trip!
For more information about the MIT reactor visit their website at http://web.mit.edu/nrl/www/index.html to learn more about the MITR-II reactor and nuclear reactors in general.
This week we performed an experiment with the computer and the nxt robot. We used a computer program that recorded all of the data that the robot collected and reported it onto excel. Using excel we placed all of the data onto graphs to observe our results.
In class..
We were curious to see how efficient solar energy was. Starting off my group used a light and the robotic device that could collect light. We wanted to see how well the device would react at different distances. We used the distances 0, 4, 8, and 12 inches for our data. Our hypothesis for this part of our experiment was that the more distance there were between the light and the solar cells on the robot the less voltage that was going to be generated on the robot. We went ahead and did our experiment, using a ruler to measure out the distances that we were going to use. Once we were done we took the data on Excel and made them into graphs (look below).
As you can see the data proves our hypothesis correct. The graph is a downwards slope and as the cell gets farther from the light the voltage of the solar cells decreases.
Our next series of tests…
We then proceeded to testing whether the color would affect the voltage of the cell. For this test we did not need to measure from a distance (used 0 inches distance) since it wasn’t our objective. Our group chose the colors of pink, yellow, blue, and orange. My hypothesis of the results were that the brighter colors would allow the cells to have more voltage while the darker colors would decrease the voltage of the cell. After doing the tests our results were put on the graph below.
As you can see our hypothesis was wrong because the brighter colors seem to produce less voltage. It seems like the voltage of the cells does not depend on how bright the colors are but something else. I suspect the voltage of the cells depends on the wavelength of the light after the previous hypothesis was proven wrong.
Today you might be enjoying the warm heat on a cold winter night, or the air conditioner on the hot summer afternoon. Running these machines consume ALOT of resources. In fact if the consumption stays the same as the current rate Planet Earth’s natural resources will all be depleted in less than 100 years. Yes our beloved planet. It is hard to imagine life without some of the advanced technology that we have today. Some even say that technology is killing children’s minds and taking away their imagination but besides that fact technology is also depleting all of the natural resources of this planet. The more advancements in technology the more resources used up.
Well hearing that you could say that earth is pretty much screwed in the next century. It might be a little too early to say that, with all the minds out in the word someone may have a great idea that saves us. Meanwhile one of the earliest steps to reach that point is now come to be known as Solar Energy.
What is Solar Energy?
Solar Energy is the energy created by the Sun. It is light and heat. The Sun, along with secondary solar powered resources: wind and wave power, create the majority of renewable energy on Earth. Humans today have found out many ways to harness solar energy, though the efficiency of how well this will affect humankind is questionable. Methods such as solar panels , solar thermals, concentrated solar power, solar nanowires, and photovolatics all help capture the Sun’s energy. Why is this method a good way to elaborate on? Because the sun shines everyday (unless its raining) it takes little resources to capture sunlight and turn it into usable energy.
If you are interested…
Solar panels (a great way to generate electricity on a small scale): a bunch of photovolatic cells assembled together into one object.
Solar thermals: electric power plants generate heat using lenses and reflectors to concentrate the sun’s energy. Because the heat can be stored, these plants are useful because they can generate power whenever it is needed (ex. emergency power outage).
Concentrated solar power (CSP): Systems that use mirrors and lenses to concentrate a large area of sunlight.
Solar Nanowires: Nanowires are made of gallium arsenide and indium gallium phosphide, which are more efficient than silicon.
nanowires
Photovolatics: is a method of generating electrical power by converting solar radiation into electrical current.
Solar Energy Experiment:
Last week in class we were introduced to a few methods of solar energy. Tom Vales introduced to us 3 devices created that took use of light energy to work.
Stirling engine:
The Stirling engine is a compression and expansion of the vapor inside.
“1. Heat is added to the gas inside the heated cylinder (left), causing pressure to build. This forces the piston to move down. This is the part of the Stirling cycle that does the work.
2. The left piston moves up while the right piston moves down. This pushes the hot gas into the cooled cylinder, which quickly cools the gas to the temperature of the cooling source, lowering its pressure. This makes it easier to compress the gas in the next part of the cycle.
3. The piston in the cooled cylinder starts to compress the gas. Heat generated by this compression is removed by the cooling source.
4. The right piston moves up while the left piston moves down. This forces the gas into the heated cylinder, where it quickly heats up, building pressure, at which point the cycle repeats.”
Also known as a thermoelectric converter. When one leg of this device is placed in a cup of cold water and one leg is placed in a cup of hot water, some of the thermal energy from the hot water is converted into work by the converter and the fan turns. If the hot and cold water are mixed together in a large container the fan doesn’t turn. The Seebeck effect is when two different metals with ends at two different temperatures produce an electric current that makes the fan turn. It was stated in class that this device was an expensive device to build.
Mendocino Solar Motor:
This motor is made up of four solar panels attached to a block in the middle of a shaft. The motor is also made to float by some magnets (for a better idea refer to image below). When light is shined onto the solar panels the device starts to turn. This device is a cool device however Tom Vales stated that it wasn’t used for anything yet just simply a good demonstration of solar energy.
In our energy experiment our group did a series of tests and data collection to determine the relationship between mass and acceleration. Newtons second law of motion states that the force of an object is equal to the mass of the object times the acceleration of the object. Looking more closely at the equation F=m*a, one is able to rewrite it as a= F/m, this tells us that if the mass gets greater then there will be less acceleration and if the acceleration gets greater there will be less mass.
To test the hypothesis we used a some string, some masses, and an Nxt motor (allows someone input how fast the motor runs by programming it). When the program is started the motor would pull the mass to a certain height and the computer would record data like: time, power, acceleration, etc. In this experiment we changed the value of the mass but kept the power constant. Every trial run by the Nxt motor was recorded by the computer, below was our data table created from the results.
The data collected above proves Newtons 2nd law is correct: that the more mass there are the less the acceleration and the less mass there are the more the acceleration. This was based on a constant force, in this case 75.
Acceleration vs Power:
The next series of tests were to determine how the power exerted on an object affected the acceleration of the object. Newtons 2nd law says that P=F*Δx/Δt, P is the power, F is the force, Δx is the change in displacement, and Δt is the change in time. In these tests the mass stayed constant while we tested different power levels (change the value with the Nxt program). After doing the tests we obtained the information that is shown below.
Looking at the data we are able to conclude that the power is proportional to the force and everything the force is proportional to. The graph shows a linear relation between the power and acceleration.
Power level vs Power:
In these series of tests we were to determine the relationship between the power (%) and how much power was outputted in the end. Looking at the graph below and also in the data in Table 2, it looks like a linear function which means that the power(%) is proportional to the output of the power.
Discharge vs Mass:
Lastly, the group wanted to find out how the discharge (V) of the battery and the mass of the weights would affect the results of the data, the power was constant. Looking at Table 1 and the graph it is hard to say what kind of relationship it has. I think the voltage and the mass was too little to obtain good results for this test. Graph and Table 1 shown below.
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It is hard to describe what pattern is being formed in this graph.
She coughs into her hand on the train, and touches the rail she was holding on to. Later, someone going home from work boarding the same train holds on to that railing. He goes home and embraces his family. The children go to school the next day an interact with the children there. All the children go home and interact with their parents. The parents go to work and interact with their co workers. A few days later people around that area go down with a virus. This is a pandemic. The word pandemic comes from the Greek word pandemos which means “pertaining to all people”. A pandemic is a serious outbreak of a infectious disease; it is when a disease emerges from someone and it is easily transferable from person to person. A pandemic is an epidemic of disease that is spreading rapidly into human populations across a large area. For example, the disease is first spotted in the United States and it spreads to China, a pandemic can spread up to even worldwide.
What is an Epidemic?
Common questions of this matter are: What is the difference between an Epidemic and a Pandemic? Well, an epidemic is a classification of a new disease that appears as new cases in a human population, it spreads at a rate that exceeds what is expected based on recent experiences. An epidemic is only localized to a city or small region. A pandemic is a epidemic that spreads worldwide, so the main difference is how far the disease spreads.
The World Health Organization has broken down pandemic stages into three periods and six stages.
Periods
-Interpandemic period
-Pandemic alert period
-Pandemic period.
Stages
“Stage 1 No animal influenza virus circulating among animals have been reported to cause infection in humans.
Stage 2 An animal influenza virus circulating in domesticated or wild animals is known to have caused infection in humans and is therefore considered a specific potential pandemic threat.
Stage 3 An animal or human-animal influenza reassortant virus has caused sporadic cases or small clusters of disease in people, but has not resulted in human-to-human transmission sufficient to sustain community-level outbreaks.
Stage 4 Human-to-human transmission of an animal or human-animal influenza reassortant virus able to sustain community-level outbreaks has been verified.
Stage 5 The same identified virus has caused sustained community level outbreaks in two or more countries in one WHO region.
Phase 6 In addition to the criteria defined in Phase 5, the same virus has caused sustained community level outbreaks in at least one other country in another WHO region.”
– taken from http://www.medicalnewstoday.com/articles/148945.php
A recent and still ongoing pandemic is HIV/AIDs. HIV spread to the United States and to a lot of the rest of the world around 1969. HIV is the virus that causes AIDS. AIDS is currently a pandemic, it has infection rates as high as 25% in Africa.
On Semptember 20, 2011, the sustainablility and energy class expiremented with the NXT robot. We used a pre-programed command that caused the robot to move forward for a fixed amout of time. We toggled around with the power and measured the distance that it moved forward each time and at what power it was running on and then we compared it to the actual distance it was supposed to move, we also had to count how many times the wheels moved.
Looking at the data I figured out how far the robot went turning just 1 rotation (360 degrees). The distance we measured was a little different from the actual distances but it was pretty close. I found doing these experiments helped me learn more about how velocity, degrees, speed, and power are closely linked.
It is a hot summer day. Coming home from a demanding track meet you simply cannot wait to feel the cool air conditioner blow ice cold air into your face. When you turn on an air conditioner you expect immediate results. You do not turn it on and wait a few minutes for it to start working. Electricity comes from a power plant and transmitted to local substations where it gets transformed into usable voltage. Then it is distributed to the places that need it in that area, this is handled by the power grid. Everyday electricity consumers predict the minimum amount of electricity that is going to be used that day, this amount is called the baseload. The grid needs to take care of this energy production and also spikes that may happen. The demand for electricity is usually the highest in the afternoon and early evening, and also during the summer time when people run their air conditioners all day and all night. The common time for people to use their electrical appliances is called the peak useage time.
Normally people probably don’t appreciate electricity as much as they should until a power outage occurs. That is when they finally realize how much they use electricity. When you turn something on electricity immediately flows into your house and turns the object on, that is called demand. When all of the electricity customers turn something on after work it is called the demand load.
We use a lot of electricity everyday, it only makes it right to think about how to conserve energy. One way to lower the demand load is a concept called demand response. In more detail demand response makes it so that us customers can trim our electricity usage at specific times of the day.
When electricity demands peaks because of unusually hot or cold weather there might not be enough electricity to supply all of the demands. In order to avoid a power outage electric utilities call upon their emergency demand response programs. California for example have their program where large commercial and industrial customers reduce their electric load to a previously agreed upon level during emergencies. Although these things don’t happen often it sure has helped them avoid some costly outages.
Economic Demand Response:
The cost to acquire supplies increase as the demand for electricity increases. When the demand for electricity is low the supply comes from inexpensive base load generation for example, coal or nuclear power. However, when the demand for electricity is high the base load generation is exhausted and the supply comes from expensive peak load generators. Even though residents pay a flat rate for electricity, the prices constantly change throughout the year.
Electricity is more reliable with emergency demand response, and less expensive with economic demand response. Anything with more reliability with demand response and is less expensive will certainly gain popularity.
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