Neel

3/24/2010
//Prompt #1: // // After reading p. 66-71 of Chapter 3 in Electricity & Magnetism, create the following paragraphs. // // · ////Paragraph 1 – In first person, explain: 1) how analog signals are different from digital signals, 2) how semiconductors are used in electronic devices, and 3) how diodes and transistors are used. // // · ////Paragraph 2 – In first person, explain where electronics would be useful in a space mission to Mars where the goal is to ultimately search for life on Mars. //

// The difference between an analog and a digital signal is that an analog signal is signals where there are changes in that vary smoothly in time. On the other hand, a digital signal is signals where there are changes that do not vary smoothly and often fluctuate. An example is where an analog clock smoothly moves its hand to change the time. A digital clock suddenly jumps from one number to the next to indicate the time. Semiconductors are used in electronic devices because they can amplify or control the charge in the electric voltage. This can be done by adding impurities to the semiconductor. There are two types of semiconductors, N-types are negative and like to donate electrons and P-types are positive and like to gain electrons. A diode is a solid-state component that allows a current to only flow in one direction like a one-way street. An electric current can only flow from the N-type to the P-type because the N-type donates electrons and it can only flow one way.

Electronics is a vital part in space travel, such as a space mission to Mars. One example of its usefulness is in computers. Computers would be needed so that pictures and visual information could be stored on them. Another example is a space probe. Electronics would be able to power the probe and allow it to travel the surface of Mars and identify things. They will also be able to operate the probe so it can dig the ground and find minerals and other objects. Without a probe, no pictures or visuals would be available for people on Earth. These are some examples of why electronics is important for space travel. //

  Some atoms allow electricity to flow through them because they usually give away “free electrons”. These electrons are on the outermost shell and are not attracted to the nucleus as much as the closer electrons. If an atom does not have a full energy shell, it is most likely willing to give electrons away. Some atoms don’t allow electricity to flow through them probably because they have a full energy shell, and are not willing to give electrons away. For electricity to flow there needs to be a difference in electric charge on the opposite sides of a transistor. If one side has a positive charge and the other side has a negative charge, electricity will flow through it. If one side has a positive charge and the other side has a positive charge, then electricity will not flow through it. In addition, if there are like charges on both sides of the transistor and are a different amount of them, then electricity will flow through.
 * 3/28/2010**
 * [[image:nr_lightbulb.jpg width="209" height="222" align="center" caption="Figure 1: Electricity flows in only one direction through a light bulb (bottom-filament-side or side-filament-bottom)"]] ||

through them. This means if one lamp was to go out, the others would go out to because the electrons are not flowing anymore. The other type of circuit is a parallel circuit. In a parallel circuit, electrons have multiple paths. This means that some objects may get more electric current than others. If three lamps were placed parallel from each other and one was to go out, the rest would not go out because they are getting their separate flow of electric current. **
 * Voltage is the pressure that pushes the electrons through a circuit. It is measured in the units of Volts (V). An electric current is the motion or flow of electric charge inside a circuit. They are measured in the units of Amperes (A) or amps. The electric resistance resists the flow of electric current is a circuit. This can be helpful when there is too much electricity because it can take some of the current away so that it does not damage any objects. It is measured in Ohms (Ω). Electricity must flow in a complete circuit. It goes in one way and comes out the other. For continuous flow of electrons, there must be no gaps in the circuit. There are two different types of circuits, series and parallel. In a series circuit, all electrons take the same path. If three lamps were placed in a series, all of them will get the same amount of electric current because all of the electrons are flowing


 * [[image:nr_parallelcircuit2.jpg align="center" caption="Figure 2: A simple series circuit. The 9 Volt battery proves 3 volts across each lamp. "]] ||


 * 4/11/2010**


 * The History of Rocketry**

One of the first devices to successfully utilize the basic principles of rocket flight was a device known as the aeolipile. It was created in around 100 B.C. by a Greek inventor, Hero of Alexandria. He mounted a sphere on top of a water kettle and a fire under the kettle turned the water in to steam. Gas traveled through the pipes of the sphere. Two tubes on the outside of the sphere allowed the gas to escape and gave a thrust to the sphere which caused it to rotate.


 * [[image:nr_firstrocket.jpg width="237" height="278" align="center" caption="Figure 1: A diagram of the aeolipile, one of the first devices to successfully employ the essential principles of rocket flight."]] ||

The dates of the first true rockets are uncertain. Early rocket-like devices appeared periodically throughout history records of different cultures. It is possible that the first true rockets were developed by accident. During the first century A.D., the Chinese accidentally produced a mixture of saltpeter, sulfur, and charcoal dust. This mixture created gunpowder which was used during religious festivals by filling tubes with a mixture and throwing them into a fire. Some tubes, however, failed to explode and skittered out of the fire propelled by the gases and sparks produced by the burning fire.

The Chinese began experimenting with the gunpowder-filled tubes. They started to attach bamboo tubes to arrows and launched them with bows. They soon learned that the gunpowder tubes could launch themselves because of the power provided by the escaping gas. The first reporting date of true rocket usage was in 1232 during the battle of Kai-Keng. The Mongols were attacked by the Chinese with arrows of flying fire. These arrows were a form of a solid-propellant rocket. Following this battle, the Mongols created their own rockets and may have been responsible for the spreading of rockets into Europe. Many rocket experiments were reported between the 13th and 15th centuries. Almost all of the uses for rockets at this time were for warfare or fireworks.


 * [[image:nr_chinesearrows.jpg align="center" caption="Figure 2: Chinese arrows, a weapon of gunpowder-filled tubes attached to bamboo. These gunpowder-filled tubes could launch themselves by the power of the escaping gas."]] ||

Modern rocketry began in 1898, when the idea of space exploration by rocket was proposed by Russian schoolteacher, Konstantin Tsiolkovsky. He recommended liquid propellants for rockets in order to attain a longer range. For his vision, ideas, and research, Tsiolkovsky has been called the Father of Modern Astronautics. Early in the 1900s, an American, Robert Goddard performed realistic experiments in rocketry. His earliest experiments were with solid propellant rockets. Later, he began experimenting with different solid fuels to measure the exhaust velocities of the burning gases. In spite of difficulties, Goddard accomplished his first successful flight with a liquid-propellant rocket on March 26, 1926. His experiments in liquid-propellant rockets continued and his rockets became bigger and were able to fly higher. For Goddard’s achievements, he has been known as the Father of Modern Rocketry.

At around the same time, small rocket societies were created all over the world. The formation of a society in Germany called the Verein fur Raumschiffahrt (Society for Space Travel), led to the creation of the V-2 Rocket which was used against London in World War II. By the end of the war, German rocket scientists and engineers had the plans of creating rockets and missiles that were capable of flying the span of the Atlantic Ocean and landing in the United States.

In late 1957, the Soviet Union launched an Earth-orbiting artificial satellite. It was called Sputnik I, and was the first successful entry in a race for space between two superpower nations. In Russian, Sputnik means satellite. In January 1958, the United States army launched Explorer I. In October of the same year, an organization was created known as NASA (National Aeronautics and Space Administration). They became a national group with a goal of peaceful exploration of space to benefit everyone. Before long, many machines and people were launched into space and machines orbited Earth and landed on the moon. Space was suddenly opened up for exploration. Satellites gave scientists the opportunity to analyze our planet, forecast the weather, and communicate around the globe.

The rocket has evolved dramatically since its accidental start when gunpowder was produced by the Chinese. Rockets have opened the door to direct space exploration by humankind.

__**Scratch Programming Rocket Simulation**__

media type="custom" key="5925023"

1) The simulation represents the basic stages of rocket flight. 2) Click on the green flag once to start the simulation. 3) Turn on the volume to listen for sounds. 4) To stop the simulation, click on the red flag once. 5) When the simulation is over, click on the green flag once to replay it.
 * Instructions:**


 * Entry #4: Rocket Parts** (4/17/10)



There are many parts of the rocket that affect its flight. The nose cone helps with the aerodynamics by guiding air around the rocket. The body tube is the main structual part of the rocket. The launch lug helps guide the rocket straight after launch. The recovery system is a device that is utilized to help the rocket return back. The recovery wadding protects the recovery system from getting burned by ejection gases. The fins helps keeps the rocket straight during flight. The motor mound holds the motor in place. The rocket motor is a safe device that must be changed after every flight.
 * Parts of the Rocket:**

The purpose of this experiment was to figure out if the mass of a rocket affected the height of its apogee. During the experiment when the rocket was on the launch pad, there were different forces acting on the rocket. The force of gravity was pushing down on the rocket and the force of the launch pad was pushing up. When the rocket was lifting off, there was gravity and air resistance pushing down, but the force of the thrust was stronger which made the rocket fly up. During coasting, the force of gravity and air resistance was pushing down on the rocket. There is no thrust because the rocket is flying due to its inertia. It was hypothesized that the lighter the mass of the rocket, the higher it will fly up because if a rocket as a lower mass, it has less inertia to overcome and therefore has more fuel to be in flight longer and have a higher apogee.
 * Launch Lab Analysis Report**

Majority of the data was an inverse relationship. The other part of the data had no relationship. The lowest mass of a rocket was 41.1g and the highest mass of a rocket was 46.0g. The lowest apogee of a rocket was 64.9m and the highest apogee of a rocket was 107.2m. According to most of the data, the lower the mass of the rocket, the higher the apogee was. The hypothesis was confirmed for the most part because it was hypothesized that the lower the mass of the rocket, the higher the apogee. There were some points in the data that showed that some of the lighter rockets did not fly as high. The lightest rocket, 41.1g, flew about 79m high and the heaviest rocket, 46g, flew 64.9m.



5/2/2010


 * The History of Robotics**



Robotics refers to the engineering science and technology of robots, their design, and application. The word robot became popular by Karel Capek, a Czech writer who wrote a play called R.U.R. (Rossum’s Universal Robots. He claims that his brother, Josef, was the actual inventor of the word “robot”. He created the word from the Czech word “robota” which meant servitude. Many robots were constructed before computer-controlled mechanisms. The world’s first robot named Televox, operated through the telephone system. The Televox is seen in Figure 1. It was constructed in 1927 in the United States. Just a year later, in 1928, Makoto Nishimura produced Japan’s first robot, Gakutensoku.



The Unimate, the first industrial robot is seen in Figure 2. It began working on the General Motors assembly line in 1961. The Rancho Arm was a robotic arm that helped handicapped patients at a hospital in Downey, California. This robotic arm was brought to Stanford University in 1963. In the winter of 1970, the Soviet Union explores the surface of the moon with the lunar vehicle, Lunokhod 1. This was the first roving remote-controlled robot to land on another world.

Takeo Kanade created the first “direct drive arm” in 1981. Being the first of its kind, the arm’s motors were enclosed in the robot itself, eliminating long transmissions. IBM then released its first personal computer (PC). The actual name of the device popularized the term “personal computer”. In October 2000, the United Nations estimated that there were 742,500 industrial robots in the world; more than half of them being used in Japan. In 2006, Cornell University showed its “Starfish” robot. It was a four-legged robot capable of self modeling and learning to walk even after being damaged. In 2007, TOMY launched an entertainment robot, i-sobot. It was a humanoid robot which was capable of not only walking like a human being, but also punching, kicking, and other entertaining tricks.


 * 5/7/10

Course Challenge** We used the LEGO Mindstorms program to create codes for a robot. The challenge in the video below is called the “Course Challenge”. The objective of this challenge was to keep the robot on the blue tape while performing a series of actions. media type="custom" key="6066075" The programming code is seen in Figure 1. There are a series of blocks which serve different purposes. The first three blocks tell the robot to move forward with 100% power for 1 rotation each. The first three blocks are sending the actions to ports B and C (the wheels). The fourth block tells the robot to continue moving forward with only 40% power for 1 rotation. The next block tells the robot to turn right with 50% power. The next block tells the robot to move forward with 100% power for 1 rotation. The next block tells the robot to move forward with 20% power for 1 rotation. The next block tells the robot to turn left with 50% power. The next block tells the robot to move forward with 100% power for 1 rotation. The next block tells the robot to move backwards with 75% power for 1 rotation. The last block tells the robot to turn to the right with 100% for 5 rotations.


 * Characteristics of Life (5/18/10)**

There are eight characteristics that determine whether something is living or non-living. Something must have all eight characteristics to be considered living. The first characteristic is that living things are made up of cells. A human cell is seen in Figure 1. The second characteristic is that living things need materials such as food, water, and oxygen. Living things also need certain minerals and take what they need from the environment. The third characteristic is homeostatic. Living things always stay the same inside despite the changes in the environment. The fourth characteristic is responding to stimuli. Living things have a response by reacting to stimuli. Some living things have locomotion which is the ability to move from place to place on its own. The fifth characteristic is reproduction. Living things must reproduce offspring of their own kind. There are two types of reproduction; sexual and asexual. The sixth characteristic is growth. Living things develop from simple forms to more complex forms. Growth happens differently at different rates for different living things. The seventh characteristic is adaption. Living things can make modifications to make it suitable for life. The last characteristic is respiration. Living things release the energy that is stored in the chemical bonds of sugars that are found in foods. Humans need oxygen to release the energy. These characteristics are important because they determine whether something is living or non-living.