Month: November 2013

Electromagnet

Purpose- The purpose of this lab is to learn about electromagnetism and create an electromagnet using a piece of metal and copper wire that is strong enough to pick up paperclips, nails, etc. Each teams are provided with the same amount of materials and task to build a magnet with the knowledge they learned in class.

Background- An electromagnet is a type ofmagnet in which themagnetic field is produced byelectric current. An electric current flowing in a wire creates a magnetic field around the wire. To concentrate the magnetic field, in an electromagnet the wire is wound into acoil with many turns of wire lying side by side. The magnetic field of all the turns of wire passes through the center of the coil, creating a strong magnetic field. Current is produced in a conductor when it is moved through a magnetic field because the magnetic lines of force are applying a force on the free electrons in the conductor and causing them to move. This process of generating current in a conductor by placing the conductor in a changing magnetic field is called induction.

Materials-

• DC generator
• Sandpaper
• Piece of metal (nail, bolt, disk, etc)
• Box of paperclips
• Voltmeter
• Electrical tape
• 40 ft of copper wire

Procedure-

1.  First prepare your materials by having it in front of you.
2. Have one end of the 40 ft copper wire in one hand and your metal piece in another.
3. Leave 8 inches of wire loose, then wrap the rest of copper wire around your metal. Try not to overlap the wires
4. Another person on your team should hold the rest of the wire so the wire won’t bend or break.
5. Leave about 8 inches of wire loose at end after you finished wrapping your metal.
6. Using the sandpaper, scrap off the end of the copper wire.
7. Attach the two ends of your wire to the alligator clips.
8. Now turn on the DC generator. Make sure it producing 5 volt.
9. Place the magnet into the box of paperclips.
10. Lift slowly away from the box onto the table.
11. Count how many paperclips was picked up.
12. Record your data.

Questions-

1. Explain how you can improve your magnet to pick up more paper clips.
2. How does the number of times you wrap the wire around the nail affect the strength of the nail?
3. How does the thickness or length of the nail affect the electromagnets strength?
4. Why must you wind the wire in the same direction around the iron core to make make the electromagnet?
5. Why must you use an iron core to make an electro magnet? Why can you use things like plastic or aluminum?

Last week, I had a great discussion with my teammates and we came up with a great experiment to perform in front of high school students. We decided to have an introduction about magnetism, which is a force of attraction or repulsion that acts at a distance. We will also explain that it is due to a concept called magnetic field, which is caused by moving electrically charged particles. Our introduction also includes electromagnetic induction. According to Wikipedia, it is the production of a potential difference (voltage) across a conductor when it is exposed to a varying magnetic field. We want the students to be engaged in the experiment. We will make a competition and divide the class into two groups. We will guide the youth to make their own magnets using copper wires and a piece of metal. Their task is to pick up as many paperclips as they can.

This type of competition will generate interest and excitement for the topic covered. We would like the students to use a team approach rather than individual approach. As far as I’m concerned, I think that the competition will be appropriate because the winner will have some candies. So, we can see rivalry between the two teams.

The purpose of the experiment is to make the young apprentices practice what they just learned from us and get an idea how energy can be generated. Additionally, the students will have some useful information about sustainability, energy, and technology.

This week, we had another experiment related to sustainability, energy, and technology, but it specifically focused on the solar energy. In order to make this lab we needed to use the appropriate materials such as a flashlight, a small solar panel, ruler, and some transparent color papers. This time the lab took us two classes because the experiment was divided into two measurements.

For the first half of the observation, the experiment investigates how changes in light intensity, (distance from the light source) affects the amount of current and voltage a solar cell can produce. My classmate and I were asked to put the light at various distances and then see how much light reached the panel. Later on, we recorded the voltages for each distance with the aid of the excel sheet. After collecting all the data needed, we made a graph to explore the measurements that we got. We concluded that the distance from the flashlight will affect the solar cell output. The intensity of light on the solar panel will decrease, due to its distance from the cell. This occurs because many waves including light will travel away from the filament in a circular motion and not straight lines directly towards the solar panel. As a conclusion, the further away the light is, the fewer rays will hit the panel, and the less voltage will be generated.

 

In the second half of the experiment, we kept the distance constant but utilized different colors. It was revealed that changing the colors of light would affect the solar cell output as each color of light has a different frequency. We could determine this from Einstein’s theory of photons being directly proportional to frequency. The theory states that Energy=(Planck’s constant*speed)/Wavelength.All the colours have the same speed, but various wavelengths, which, according to the equation above, modifies the value for energy (solar output). As long as the wavelength is the denominator of the equation, we can say “the larger the wavelength, the lower the energy” (Such as the red light in the experiment. See chart below). However, lights that have large energy photons must have low wavelength such as the green color.

The chart confirms that the voltage output from the green light is greater than the red light.

 

 

http://www.123helpme.com/view.asp?id=147841

Two weeks ago, we had a new exciting experiment. The activity stated the Faraday’s law and electromagnetism. When Faraday performed an experiment with a magnet and coil, he made a specific observation. During this experiment, he found how emf is induced in the coil when flux linked with it changes. In order to achieve this observation we needed some useful materials such as a generator, voltage probe, NXT, and NXT adopter. We started by connecting the generator to a voltage probe, which in turn was connected to the NXT. Like other experiments, we could determine the voltages using an Excel sheet. My teammates and I made five trials with a diverse number of shakes. As far as I’m concerned, I believe that the interval of time that we utilized did not have an effect on our experiment because we kept the same interval on each of the five trials. After collecting all the measurements in the lab and with the aid of the Excel sheet, we made a graph to analyze the relationship between the number of shakes and the voltage output.

The experiment was made to recognize the voltage of the modification in flux because of shaking a magnet. Any change in the magnetic environment of the coil wire will immediately produce a voltage to be “induced” in the coil. No matter by how much the change is done, the voltage will always be generated. This could be clearly determined by the fact that at 0 shakes; we did not have an important modification in voltage. The greater the number of shakes, the higher is the number of voltages. The change could be originated by modifying the magnetic field strength such as moving a magnet inside a coil of wire, which was our case in the experiment. When a magnet is moved into a coil of wire, it changes the magnetic field and magnetic flux through the coil. Then, a voltage will be generated in the coil according to Faraday’s Law.

The Faraday’s Law plays a significant role in our real life applications. Some of the devices that are related to this theory are; induction stoves, tape players, metal detectors, and transformers.

 

http://www.electrical4u.com/faraday-law-of-electromagnetic-induction

http://hyperphysics.phy-astr.gsu.edu/hbase/electric/farlaw.html

Few weeks ago, we went to MIT to see their nuclear reactor but this time we changed from the atmosphere of institutions and took a field trip to the Museum of science. We walked as a group from Suffolk to the museum, which is located in Cambridge. We were asked to examine, explore, and go through all the expositions that were related to sustainability, energy, and technology.

Fortunately, we arrived exactly when the electricity exhibit started in the theatre of electricity. An expert in that field was explaining to the audience the use of Faraday’s cage theory. He started by defining high voltage as the possibility of causing a spark in the air, and the danger of electric shock by contact. He later on made some electrical discharges, that we could see with the naked eye, to strengthen his argument. As we went through the presentation, the expert got our real attention and encouraged us to be engaged in his presentation. Therefore, he entered the cage and allowed high-voltage discharges from an electrostatic generator to strike the outside of the cage. We were all feared by the bad consequences that might happen but the expositor explained that the Faraday’s cage distributes the charge around the cage’s exterior and cancels out electric charges within the cage’s interior. In other words, it is a hollow conductor, in which the charge remains on the external surface of the cage. As far as I’m concerned, I believe that what made the experiment captivating was the fact that the guide could make music by changing the value of the current. The high voltage electricity was released from the electrostatic generator, which in turn reached the poles and made some specific musical tones. The experiment was thought provoking and made me speechless.

 

After finishing the presentation, we left the electricity theatre and went to the solar section. The Section displays a range of activities, which aim to bring about a “clean energy society”. Its focus is to present exhibitions that create an interest in global environmental issues, as well as to raise the profile of photovoltaic science among the younger generation (future leaders). One of the exhibits was a “mini” solar panel, which transforms sunlight into electricity. The panels are designed so that the charges will flow in one direction and can be used to do electrical work.

After that, my teammates and I went to the wind section, which mostly was about wind turbines. People have been using wind power for centuries to accomplish various tasks.  The concept of wind turbines is simple. They convert the energy of moving air into electricity. According to legacy.mos.org, the wind spins the turbine’s curved blades, creating torque that turns a gear train and drives a generator. The electric current that will be generated can be stored in different ways, but mainly it is stored in batteries.

With the massive exhibits exposed in the museum, I took the initiative with my teammates and started thinking about our High school project. The museum gave us plenty ideas that helped us sort out the best suggestion.

 

http://science.howstuffworks.com/faraday-cage.htm

http://panasonic.net/sanyo/solarark/en/lab/

http://legacy.mos.org/energized/photovoltaic.php

http://legacy.mos.org/energized/wind.php

Short while ago, our sustainability, energy and technology class had an exclusive opportunity to present us Tom Vales. He is an amazing professor who knew how to catch the students’ attention with his entertaining gadgets and machines. He showed us sources of energy that were related to the course.

Robert Stirling invented the Stirling engine and that from where the name of the creation came from. According to (comptune.com), Robert added to the design a “regenerator” which acts as a heat exchanger and heat-recycling device, increasing the efficiency dramatically. The concept of the device is simple. Imagine we are working on this kind of engine.

Heat to the gas in the left cylinder causes pressure to build. This forces the piston down, doing work. The left piston moves up while the right piston moves down. This drive the heated gas into the right cylinder and the gas cools as it enters the cylinder. Therefore, the right cylinder compresses the cooled gas, so the heat generated by the compression is directly removed by the cooling source. Now the same process is repeated but from the cool side. The right cylinder moves down while the right cylinder moves up, and the gas heats up as it is driven to the cylinder. The machine was utilized for many purposes mainly for pumping water and is efficient because it does not use plenty fuel.

Another gadget that Tom showed us was the Tesla coil. It is a resonant transformer invented by Nikola Tesla in 1891. It is a ultra high tool that can take 120-volt alternating current and generate almost 1 million volts. It can send power wirelessly in the air and light a bulb that is a bit distant. To see the efficiency of tesla coil it you need to put the bulb right next to it Tesla concluded that everybody needed a Tesla generator because it is useful and efficient, but his research was never completed.

Another invention that Tom presented us was the Mendocino motor. It is a solar powered magnetically levitated motor. The motor hangs in its own magnetic field and transforms light into electricity and magnetism, which are later on converted into the movement of the motor. Such gadgets demonstrate the advance of technology exploring various fields such as electric motors, magnetism, and solar power generation.

Finally, I’d like to thank Tom for showing us different kinds of machines that I was not aware of their existence.

 

 

http://comptune.com/tincan/hk1/HK1_Plans.pdf

http://auto.howstuffworks.com/stirling-engine1.htm

http://overunitymotor822.weebly.com/tesla-coils-a-short-summary.html

http://makezine.com/projects/make-31/mendocino-motor-2/

 

Our last class was a bit different from the others. We had to walk to MIT to see their nuclear reactor. I knew that we were heading to an interesting achievement that MIT students did since the professor asked us to send her our addresses and names in order to give them to MIT’s staff. The nuclear reactor was highly secured. After checking in, I was asked to wear a radiation detector, which is a device that helped us detect/track high-energy particles. Afterwards, one of the MIT’s staff took us to a classroom where he explained the concept and the uniqueness of MIT’s nuclear reactor.

Unlike the other nuclear reactors, the one in MIT does not have commercial purposes, but it was made for scientific research and experiments. As far as I’m concerned, I believe that traditional cancer treatments are not as much effective as the use of nuclear reactor. MIT’s nuclear reactor was used for medicine purposes to cure people who suffered from cancer with less severe side effects. The nuclear reactor used a treatment called NCT which stands for Neutron capture Therapy. It is “a cutting-edge treatment method that uses neutrons captured during operation of a nuclear reactor to irradiate the tumor.” (Phys.org).

The lecturer started by giving us an idea of how the nuclear reactor does work and by presenting the various components of the reactor. He later on explained two concepts of nuclear energy: fusion and fission. The two terms might be similar in terms of words but different in terms of definition.  According to the article published in the university of Wisconsin nuclear reactor tour, Fission is defined as “a nuclear reaction in which atomic nucleus splits, or fissions, into fragments of comparable mass, with the release of large amounts of energy in the form of heat and radiation.” However, fusion is defined as a combination of light nuclei.

After the presentation, we were led to the reactor itself where the guide explained us that the nuclear reactor is smaller than the regular average size. In the entrance,  we could see the high measurements of security that have been set up inside the reactor. The guide showed us a board, which included the names of workers accompanied with light bulbs. So, in case of an emergency, workers could know easily who of the employees is still inside the nuclear reactor. Also, the guide showed us the most significant “piece” which consisted in controlling all the components of the nuclear reactor. With the aid of light bulbs, workers could see which component is working and which is not.

I learned a lot from the tour and I liked the fact that our course was diversified by such interesting activities.

 

“Particle Detector.” Wikipedia. Wikimedia Foundation, 31 Oct. 2013. Web. 03 Nov. 2013. <http://en.wikipedia.org/wiki/Particle_detector>.

“Nuclear Reactor as a Cancer Cure.” Nuclear Reactor as a Cancer Cure. N.p., 03 May 2005. Web. 03 Nov. 2013. <http://phys.org/news3245.html>.