Love Water Music

Rosa E, Bijan A, Briana M, Eduardo C, Sam B

Title: Endothermic and Exothermic Reactions

Purpose: The purpose of this experiment is to observe endothermic and exothermic reactions with sodium bicarbonate, copper sulfate, magnesium metals and citric acid.

Background: Endothermic and Exothermic reactions relate to sustainability because they occur constantly in energy production. For example in water cooled nuclear reactors, heat from the reactors core is absorbed by the water and becomes steam which is an endothermic reaction. And inversely when the steam in the nuclear reactor condenses back into its liquid state energy is released causing an exothermic reaction.

Procedure: Endothermic
1. Get citric acid and sodium bicarbonate
2. Measure 15 grams of sodium bicarbonate on a scale (remember to zero out plastic cup)
3. Measure out 25 mL of citric acid into a beaker
4. Drop in temperature probe, hit start (make sure to get initial temp)
5. Mix solutions (under hood) and stir until reaction is complete
6. Record the changes in temperature

In the second section of this experiment 25mL of citric acid and 15g of sodium bicarbonate will be combined in a 600mL beaker, and the change in temperature will be monitored. It is expected that the temperature will drop showing an example of an endothermic reaction.

Exothermic
1. Get copper sulfate and Magnesium metal strips
2. Measure out 5 grams of magnesium metal (zero out plastic cup)
3. Measure 100 mL of copper sulfate and pour into beaker
4. Insert temperature probe, (get initial temp)
5. Mix solutions and stir until reaction is complete
6. Record changes in temperature

– The First part of this experiment is to combine of 5g of magnesium and 100mL of Copper Sulfate in a 600mL beaker and monitor the change in temperature. The temperature is expected to rise in this portion of the experiment showing us an exothermic reaction

Data: For the first part of the experiment, the initial temperature was at 21.6 degrees Celsius, after the reaction of copper sulfate and magnesium metal strips the final temperature progressed to 27.4 degrees Celsius. The change in temperature was 5.8 degrees Celsius which indicated an exothermic reaction as predicted.

The second part of this experiment began with an initial temperature of 21.5 degrees Celsius. After the mixture of citric acid and sodium bicarbonate the final temperature was 12.9 degrees Celsius with a change in temperature of -8.6 degrees Celsius. This displays an endothermic reaction.

Analysis: The data collected in this lab illustrates the properties of Endothermic and Exothermic chemical reactions. They are fundamental principles of chemistry and play a vital role in life, from energy production to combustion engines and more.

Discussion: On the day of presentations all of the groups presented their power points. Our presentation went well, all members of the group presenting a slide. An aspect that was weak in our presentation was in relating the experiment to sustainability. Two groups from our class arrived to present, but only one from the other class, so we presented our presentation to one member of the group from the other class. The other group from our class presented to the other person. We intended to have the other group do the experiment on their own and be there as guiding influences. Since we were only doing the experiment with one person that would have been rude. Instead we all worked together to do the experiment, and made sure that the person from the other group was involved in the interesting parts of the reaction. Over all the presentation went well. The experiments behaved in the ways they were expected to. The person we were presenting to handled the experiment well. Safety goggles and gloves were worn, and a fume hood was used as a precaution.

More on Endothermic and exothermic reactions:

Photosynthesis is an example of an endothermic chemical reaction. In this process, plants use the energy from the sun to convert carbon dioxide and water into glucose and oxygen.

While combustion is an example of an exothermic reaction.

Here are links to some videos on endothermic and exothermic reactions:

http://www.youtube.com/watch?v=XYRCXoFWPZw    a basic example

http://www.youtube.com/watch?v=cBy4Q6A8Hfw       a more academic example

The SET class did an experiment with solar panels. Two different experiments were done that tested the efficiency of the solar panels. The first experiment was to test the efficiency of the solar panel as the distance between the solar panel and the light source grew. The second experiment was to test the efficiency of the solar panel when the light source was covered with different colored lenses. It was observed that the solar panel put out les energy as it was mover farther away from the light source. It was later observed that the solar panel had the greatest output when an orange filter was used, which was followed by the less efficient blue filter, and then lastly the yellow filter.

Solar panels are also called photovoltaic cell which implies the ability to convert light energy into electricity. These cells are usually made of semiconductors. Silicon is a common semiconductor used.  Semiconductors are used because when the light hits the cell a certain amount of the light is absorbed by the semiconductor. This absorbed light/energy allows electrons in the semiconductor to flow. When electrons flow a current is produced, and by placing a bit of metal somewhere on the solar cell the current can be directed for external use.

A few weeks ago the class activity was a generator experiment. The experiment began by taking a flashlight that used a metal coil and a magnet to produce energy and shaking it. It was observed that after only a little amount of shaking the flash light began to work, emitting a bright light. Groups then deduced that the more amount of shaking that was done to the flash light the longer the light would last. And experiments were done to test this hypothesis.

The foundation for the shakable flash light lies in electromagnetic inductance. Michael Faraday discovered in the 1830’s that an electrical current was created when a magnet was passed through coil of wire. In order for an electrical current to be created the magnet needs to be perpendicular to the wire when it is passed by the conductor, so that the lines of flux disturb the conductor appropriately. These are the principles behind the shakable flash light which is also referred to as the Faraday flashlight.

In Sustainability Energy and Technology we used photovoltaic cells in order to test the voltage produced at different distances and through different colored lenses. First here is some background information on photovoltaic cells. Photovoltaic cells convert light energy into electricity through a property known as the photovoltaic effect which causes some materials to absorb photons of light and emit electrons. The emitted electrons then produce an electric current which is known as electricity. This property was first observed in 1839 by Edmund Bequerel.

In the first series of tests the distance from the light source was increased and we observed what happened to the voltage as the distance was increased. Then in the second series of tests the distance remained the same, but different colored lenses were applied, and voltage was measured. It was observed that voltage decreased as the photovoltaic cell moved further from the light source, and voltage varied with different colored lenses.

Our class took a field trip to the MIT nuclear reactor. The class met at the normal location, and then got on the T at Charles MGH. We took the train one stop to Kendal, and then walked to the nuclear reactor. I was not expecting such a long walk, and was wearing heals. Once we arrived at the nuclear reactor each student was signed in and given a radiation monitor, a device that everyone that enters the reactor must wear. The radiation monitor was checked to see what the base line was before entering the reactor. This was done by holding the device up and looking through it, once the initial value of the radiation monitor was determined it was logged by a staff member of the reactor. Once everyone was signed in those with bags deposited them in an office.

Since there was limited time the person facilitating our tour kept the pre tour lecture short. The tour guide gave us a brief description of the reactors core which is made of uranium. The uranium is placed in between two sheets of metal which is then flattened into a thin sheet. Once the sheet is flattened the edges are cut off of, the idea behind this is to create a uniform sheet of uranium dispersed within the metal. These metal-uranium sheets are placed in a hexagonal structure and are periodically rotated for optimal use. If the reactor needs to be shut down there are six shim blades that drop down and shut the system down. The shim blades are controlled by an automatic regulating rod.

The class was toured through the reactor and several research opportunities available at the reactor were discussed. The research that I found most interesting was the Boron Neutron Capture Therapy which was research that was being done on cancer patients. The patients that were participating in the research were patients with cancer that would have been very difficult to operate on like brain cancer. Unfortunately this research is not presently being done because there is not a medical doctor that is heading the research, though the reactor is looking for a doctor to head the operation.

It was also brought up that the reactor is habitually in the red, and does not make money. One of the ways the reactor does offset the costs of running is by Neutron Transmutation Doping of Silicon.

On our way out of the reactor every student had to have their hands and feet scanned for radiation by standing on a machine that scanned for radiation. When I stepped on this machine in my high heels I broke it by puncturing the membrane. I was thoroughly embarrassed, and apologized profusely and the rest of the class and I used the old school radiation scanning device.

This week in Sustainability Energy and Technology the class formed the groups we will do our presentations in. The first step in the group formation was gathering the group leaders. The group leaders were assigned by professor Shatz. Then the names of the group leaders were written on a piece of paper, and numbers were assigned to each leader per each group member that would be in their group. Next the students in the class chose numbers at random and were placed in the corresponding group.

Once all of the students were placed in groups the groups met and began brainstorming. In Bijan’s group things began slowly, with little direction or motivation seeming to be present. The group scanned some web sites, and batted around ideas. Then things got silly and the experiments that were purposed were way outside of the scope of things that could be accomplished in our class. For example large combustion reactions were proposed. Then some experiments were suggested that did not require any measurements and thus were not suitable.

Finally the group decided to do an experiment involving endothermic and exothermic reactions. And it was decided that we would need citric acid solution, baking soda, magnesium metal, hydrochloric acid, Lego NXT, temperature probe, and styrofoam cups in order to do this experiment.

An endothermic reaction is a reaction that heat goes into, and thus heat is on the reactant side of the equation. While an exothermic reaction is a reaction that involves heat leaving the reaction, and thus heat is on the product side of the reaction.

This week in class Tom Vales gave a presentation on alternative forms of energy. He brought in examples of and discussed the stirling engine, peltier device which is a thermoelectric converter and the Mendocino solar motor. I found him to be an intriguing speaker, because he seemed to truly enthusiastic about the subjects he was discussing.

The Stirling Engine is a devise that was first created in 1816 by Robert Stirling. By what I observed in class there seems to be a lot of potential for this devise, though it is not being widely used in today’s society. It is an engine which is used when the engine needs to be quiet, thus it is used in auxiliary power generators on yachts and on submarines. Mr. Vales said that there had been few changes made to the design of the devise since its birth. The stirling engine which Tom Vales brought in to class had two cylinders and used the steam produced from a cup of hot water as its external heating source and was cooled by the surrounding air.

The Peltier Device is a devise that produced work from the temperature difference between hot and cold water. When one leg of this device was placed in hot water and another in cold water the fan began to spin. This occurred because of the Seedback effect which produces an electrical currant from thermal energy by having two different metals with connections at different temperatures. This devise can be used for light weight sources of electricity with the potential of producing up to 5 volts of electricity.

Mendocino Solar Motor is a levitating motor which is powered by solar energy. The levitation is facilitated by use of magnets placed on the shaft of the motor and the base of the motor. By having the side of the magnets with similar charges facing each other in the base and the shaft levitation is produced by the repulsion of like charges. There is also a magnet which produces a magnetic field for the rotor. Besides levitation the magnets also cause a forward thrust which keeps the shaft point against the bearing plate. The rotor is a shaft with a point on the end on which four solar cells and two sets of windings are attached. At the present time this technology is being used primarily as a teaching tool, but I am excited to see what new ways people find to use this technology in the future.

Resources

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

http://www.jsd.claremont.edu/physics/demo/thrmcvtr.htm

This week in class we did a lab in which we used a program that Dr. Shatz had set up in labview. We used this program to record what happened when we lifted objects into the air. This data was then used to calculate the acceleration and power that was associated with each test.  For the first four tests a constant percent of power was used and the weight of the objects was changed for each test. During the second four tests the weight used remained the same while the percentage of power used changed. For all of the tests a single pulley system was used.

The idea behind pulley systems is that a change in direction of the force makes the object easier to lift. In single pulley systems this ease is in being able to pull down on the object instead of having to pull up while in double pulley systems a three to one mechanical advantage is produced which means that the force being exerted on the object is three times that of what is being used to apply tension on the line. In a pulley system the force is referred to as tension and it is uniform throughout the line. In order for an object to be lifted the tension in the line must be greater than the weight of the object being lifted.

Unfortunately do to technological errors the data that was generated from this experiment was lost.  Though it can be said that as the mass of an object increased the acceleration decreased, and as power increased with a constant weight the acceleration increased.

Reference

http://www.the-office.com/summerlift/pulleybasics.htm

Pandemic a Latin word meaning all people, it refers to a disease that has infected many people in several counties or on several continents. In recent history Smallpox, HIV, Tuberculosis, H1N1, and the Spanish flu have reached pandemic proportions. The average seasonal flu is not considered a pandemic; however periodically drastic changes in the influenza A virus take place and then the seasonal flu can become a pandemic. This is because the changes in the structure of the Influenza A virus can leave many people with no resistance to the disease, which allows it to spread rapidly and kill more people then would occur from the average seasonal flu. Each virus mutates frequently meaning new vaccines must constantly be created; also a vaccine can only be created once the virus has been identified. Thus in the early stages of Influenza pandemics there are no vaccines. Vaccines can often take six months to produce, and by the time they are produced if the virus is pandemic it is probably spread throughout the globe.  Industrialized nations often have contingency plans for pandemics that include contracted vaccine production, stockpiles of medical equipment, and estimations of how many people will need to be hospitalized. An informed population is also helpful to combat a pandemic. If citizens are well informed and prepared before a pandemic occurs then the compound destruction of mobs acting out of fear is minimalized. For this reason the Canadian government provides scenarios for their citizens to practice, or be aware of the potential.  The fact is that pandemics occur; it is not a question of if but when?  How will your government, community, and you yourself react when the next pandemic hits?

Sources:

http://www.thefreedictionary.com/pandemic

http://www.phac-aspc.gc.ca/ep-mu/index-eng.php

http://www.flu.gov/individualfamily/about/pandemic/index.html

This semester I am taking a seminar course on Sustainability Energy and Technology.  As part of the Technology portion of this class we have assembled Lego robots that we can program to do simple actions. This week we used these robots to study distance and velocity.  My partners and I programed the robot so that the motors that control each wheel operated at equal power for a set amount of time. We then calculated that the circumference of each wheel was (1.728 cm). which helped us understand how far the robot traveled.  This allowed us to calculate the velocity of each test, because velocity is distance divided by time.  Some of the basic conversion factures we thought about were: 360 degrees is equal to one rotation and one hundred milliseconds is equal to one second, and how distance is related to the number of turns. We did three tests, each test we set the power of the motor to a different degree, and recorded our observations. Below is the data we collected:

1)      number of wheel turns: 1.605

theoretical distance: .2772m                    % error 1st experiment (power 75) = .0834 = 8.3% actual distance .255m

2)      number of wheel turns: 1.74

theoretical distance: .300                         % error (power 80) = .0869 = 8.7%

actual distance: .275

3)      number of wheel turns: 1.966

theoretical value: .339                              % error (power 90) = .08455 = 8.5%

actual distance: ..3115

As you can see there is some experimental error in our tests. This error could have been caused by an the table not being level, the wheels skidding, or lack of precision in our measurement of the distance that the robot traveled.