Joshua

=Prompt #1:= ==== March 24, 2010 **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. ** ==== Analog and digital signals are both types of electronic signals. However, they produce signals very differently. Analog signals are produced smoothly and continuously, just like the liquid in an analog thermometer constantly moves upward as a person’s temperature increases. Digital signals are produced in jumps or steps. Many of the thermometers that we use now are digital. These types of thermometers increase/decrease by different degree intervals. As a person’s temperature changes, the numbers shown by the digital thermometer change in jumps until the thermometer finally reaches the person’s temperature. Semiconductors are elements that conduct electricity better than non metals, yet worse than metals. These elements are called metalloids. There are many metalloids in the periodic table, including silicon and germanium. By themselves, semiconductors don’t conduct electricity very well. Through a process of doping, you can change a semiconductor’s conductivity. When you add just one different atom to 10,000 silicon atoms, you can change silicon’s ability to conduct electricity entirely. The different atom creates an imbalance in the semiconductor, giving it either a positive charge or a negative charge. The n-type semiconductor contains extra electrons, while the p-type semiconductor contains extra protons. After completing this process, semiconductors can actually conduct electricity very well. Transistors and diodes are both used in electronic circuits. A diode allows electricity to flow through it in one and only one way. A diode contains one p-type semiconductor and one n-type semiconductor that are connected to each other. The n-type semiconductor is able to give electrons to the p-type semiconductor, which gladly accepts them. It is not possible to have electricity flow the other way because the p-type semiconductor cannot give away electrons, and the n-type semiconductor cannot receive electrons. A transistor is like an extremely small switch. Based on the type of electronic signals that a transistor receives, it can either block the flow of electric currents or allow currents to pass through it.

Electronics are an essential key to finding life on Mars. They can be used in many different ways. NASA used electronics to design a robot that could rove Mars, searching for life, water, and giving Scientists on earth vital information used to find life on Mars. For instance, pictures and video tapes can be taken by the robot, giving Scientists an understanding of Mars’ landscape. Scientists use electronic signals to make the robot move. The signals are created with the use of computers, which also run on electricity. Many of the devices on a spaceship such as the communication tools also run on electricity.
 * · 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. **


 * Search for Life on Mars Mission (SLMM) – Entry 2 **

** March 29, 2010 **
 Although you may not know it, everything contains electricity. Electricity is the flow of electrons or, in simpler terms, the movement of electrons from one atom to another. There are many different substances. However, only certain ones can conduct electricity well. A substance’s ability to conduct electricity is decided by the atomic structure of that substance. When an atom **doesn’t have** a full energy shell, it will be more likely to give away electrons than an atom **with** a full energy shell. When electrons are easy to give away, they are called “free electrons.” Electricity can only flow if there are different charges on the opposite ends of a conductor. When this occurs, it is said that there is voltage across the ends of the conductor. Voltage is the pressure that pushes electrons, creating an electric current. Voltage is measures in units called Volts (V). As long as there are unequal charges on opposite ends of the conductor, electricity will flow, being supplied by Voltage. Electric current is the flow of electric charge. Electric current is measured in Amperes, or Amps. The amount of electric current flow in a circuit depends on two things. One is the amount of voltage pushing the electrons. The other is the amount of electrical resistance that the conductor offers. Electric resistance is measured in ohms, coming from the Greek “Omega”. The more ohms of resistance, the more a conductor is able to resist the flow of electricity. Electricity must flow through a complete circle, or circuit. Usually, the positive charge is at the top of the battery, and the negative charge is at the bottom of the battery. If a full circle is not completed, it is impossible for electricity to flow. In most cases, there are two main types of circuits used to allow electricity flow. One is a series circuit, while the other is a parallel circuit. In a series circuit, there is only one pathway for electricity to flow through. This means that the electric current passing through each electrical device is always the same. See Figure 1.

//Figure 1. A Series Circuit//

The other main type of circuit is a parallel circuit. In parallel circuits, each device -- in this case light -- has its own path to the battery. Unlike a series circuit, the current going to one lamp doesn't have to pass through the other lamps, which act as resistors in a series circuit. Because there are multiple paths in a parallel circuit, each device solely affects itself. This means that if one light is turned off, the others will stay on. All of all of the paths are connected to the same battery, each device experiences the same voltage. See Figure 2.



//Figure 2. A Parallel Circuit//

April 12, 2010

Read the document entitled “Rocket History.” This document can be downloaded from the Unit 5 – Rocketry folder under the Resources section on our class’ web page. In two or more paragraphs, summarize the history of rockets. Additionally, include at least 2 pictures that you have __drawn__ and uploaded to supplement your written work. Your final log entry should contain: · A title describing the contents of the entry. · 2 paragraph summary of rocket history (can be longer). · 2 pictures that you have drawn and are related to the reading. · Correct spelling and grammar
 * SLMM – Entry 3 **

Rocketry is an emmense topic that has been studied for thousands of years. It is impossible to sum it up in two mere paragraphs. However, I will attempt to do so.

The first devices related to rocketry began around 100 B.C. in Ancient Greece. The Greek inventor Hero found a way to use steam to propel an object. Hero put a sphere on top of a bucket of water. He put a fire under the water. The water quickly began to evaporate into steam. The steam travelled through to pipes into the sphere. When this was done, some of the gas escaped creating a thrust that turned the sphere. The first real rocket was invented a long time after Hero by the Chinese. Around 100 A.D, the Chinese had invented a formula for gunpowder using saltpeter, sulfer, and charcoal dust. The Chinese packed their gunpowder into bamboo tubes. They discovered that when lit on fire, these tubes would explode. The Chinese became intrigued and began experimenting more and more until they tried attatching these gunpowder filled tubes to an arrow. They realized that when lit, the arrow would be propel itself due to the power produced by escaping gas. They had created the first rocket!!!

Figure 1: Hero's Invention

FIgure 2: Chinese Fire Arrow

Modern rocketry began in 1898 when the Russian schoolteacher Konstantin Tsiolkovsky proposed that people explore space using rockets. He also believed that rockets could achieve greater altitude by using liquid propelants. He carefully explained his ideas to others, earning himself the nickname, "The Father of Modern Astronautics". Tsiolkovsky's revolutionary ideas led to the rocketry that we know today.

Rocket Flight Stages Simulation **

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Instructions for running Scratch Rocket Simulation: This simulation is of a rocket flight from earth to mars. You start the simulation by clicking the green flag in the top right corner of the frame. To stop the simulation, click the red circle right next to the green flag. Also, be sure to turn on the sound on your computer.

Entry #4: Rocket Parts 4/16/10



In our rocket, their are eight main components. The nose cone guides airflow around the rocket, enabling the rocket to reach higher altitudes by experiencing less air resistence. The body tube is a cylander, in this case made of a strong paper tube holds the recovery system, recovery wadding, and motor mount. The recovery system is a device that allows the rocket or object being ejected from the rocket to have a safe descent so that it may be used again. In this case, the recovery system is a parachute. The recovery wadding protects the recovery system from hot ejection charge gases. We used a piece of paper tissue. The launch lug guides the rocket straight off the launch pad so that the rocket has a very defined flight up until the apogee.There are three fins on the rocket that keep it moving straight throughout the course of the rocket's flight. A rocket motor is a safe but non-reusable device. This means that each motor can only be used for one flight. Finally, the motor mount holds the rocket in place. I hope that this gives you a better understanding of the parts of our rocket.

Entry 5- April 27, 2010 **The purpose of this experiment was to discover how the mass of a rocket affects the altitude that it acquires. In a rocket flight, there are many forces acting upon the rocket. To lift the rocket into the air, there is a thrust that occurs. In this scenario, the rocket is lit and a package of gunpowder explodes, thrusting the rocket upward. When a rocket is lifted into the air, it is known as lift-off. After lift-off, the rocket goes through a period known as powered flight in which the lit gunpowder continues to thrust the rocket upward. When the powered flight ends, the rocket continues its flight upward for a slight period of time until the air resistance is too great and the rocket reaches its apogee, or peak of flight. It was hypothesized that the greater the mass of the rocket, the less altitude the rocket would reach because it would take less gunpowder to shoot a light rocket up in the air than a heavy rocket.**

 Graph 1 – Relationship between rocket mass and rocket apogee.

of subsequent rockets did not decrease as their mass increased. In fact, the four highest apogees were spread evenly across the range in rocket mass.**
 * Graph 1 compares the calculated rocket apogee with rocket mass. In this experiment, the data showed no clear relationship between the rocket mass and the rocket apogee. The mass of the rocket had no affect on the height the rocket attained. The apogees of the various rockets ranged from 74 meters to 128 meters. It was hypothesized that the relationship between rocket apogee and rocket mass would be inversely and linearly related. In other words, as the rocket mass increased, the apogee height would decrease linearly. This was not the case, as shown in Graph 1. While the lightest rocket did have the highest apogee at 128 meters, the apogee

Entry 6: May 2, 2010

Robotics is an extremely vast field that has been around for thousands of years. The first traces we have of robotics date back to 350 BC when the Greek mathematician Archytas invented a mechanical bird that he called, "The Pigeon." "The Pigeon" is not only a device that began study of robotics. Archytas' invention is considered the first model airplane, and serves as one of the first studies of flight ever. The next huge step that led to modern robotics was an invention by Leonardo DaVinci. Davinci created a mechanical device that looked and moved like an armoured knight. While Davinci's mechanism was meant for the amusement of royalty, it was a huge leap for the development of robotics. Leonardo Davinci's robot led to other revolutionary ideas such as Charles Babbage's robotics designs, Nikola Tesla's robotic boat, and Jacques de Vaucanson's automatas, robots that could play music.

Modern Robotics

While it is true that in a sense, robots were first invented by the Greeks, the first industrial robots were not invented until the early 1960s. In 1962, the first industrial robot was invented. This robot, the Unimate, was designed to complete repetitive or dangerous tasks for the General Motors company. The Unimate was successful, and companies began to create more and more of them. After the invention of the Unimate, many more robotic advances occurred. Over the past 20 years, we have taken robotics to a whole new level by testing them in space. The most momentous event in space robotics occurred when NASA successfully landed the space rover "Spirit" onto Mars.

These two paragraphs can only give one a microscopic view of such a vast topic. However, even in such a short amount of words, it is evident that robotics has evolved tremendously throughout the centuries. Now, it falls into our hands to create the next advancment in robotics.

Figure 1: Archytas, the inventor of the "Pigeon"

Figure 2: The Unimate, a robot working for General Motors

Entry 7

May 10, 2010 Dance Party Challenge

The goal of our challenge was to create a robot that would move to the music of 'The Cha-Cha Slide". We first had to write a code that directed our robot to do the correct motions that related to the music. We had to make sure that all the angle turns were correct and that the robot moved in any given direction for a reasonable amount of time. Finally, we added a little twist of our own to the dance... When all the code was complete, we captured our robot's movement on a video. Enjoy!

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Video #1: Our robot's movement on tape



Figure # 1: The first half of our robot's code

To begin our code, shown in figure one, we created an big orange loop, which enables us to repeat all the steps within the loop. The first block inside the orange repeat loop is an orange sound block. This block causes the robot to begin moving when music or noise occurs. The sound sensor is connected to port 2 Next, there is a smaller orange loop that surrounds only two green (movement) blocks. This orange loop directs the robot to repeat the next two movement bricks 3 times. The first movement block tells the robot to move forward for half a second at 75% speed. The wheel motors are connected to port B and C. The second movement block tells the robot to move backward for half a second at 75% speed. As said earlier, these are repeated 3 times. The third movement block directs the robot to turn left 150 degrees. The fourth block tells the robot to move forward one second at 75% speed. The fifth movement block tells the robot to turn right 210 degrees. The sixth movement block directs the robot to move backward for one second at 75% speed. The seventh movement block directs the robot to move forward for one second at 75% speed.

Figure 2: The second half of our code.

Figure 2 begins with the eigth movement block. This block directed the robot to move forward one second at 75% speed. The ninth movement block directs the robot to turn left 210 degrees. The tenth movement bock directs the robot to move forward for one second at 75% speed. The eleventh movement block directs the robot to turn left 190 degrees. The other half of the big orange loop is shown next, allowing all the previous actions created to be repeated once. The first item out of the repeat loop, or the twelth movement block, directs the robot to coast slightly to the left and backwards at 25% speed for 5 seconds. The thirteenth movement block directs the robot to make a full loop at 100% speed. The fourteenth block directs the robot to display a smiley face. The fifteenth block, colored orange, directs the robot to hold the smiley face image for three seconds. The final, sixteenth, block directs the robot to stop displaying the smiley face. Our dance party is complete!

Log Entry #8 8 Characteristics of Life: May 18, 2010

To be considered a live, that thing must be made of cells, need materials, be homeostatic, respond to stimuli, reproduce, grow, adapt, and must be able to respirate. These are known as the eight characteristics of life. If a thing does not have even one of these characteristics, it is not living. When an object is made of cells, it has the first characteristic of life. Cells are the basis of all living things, and have many different parts. The three main types of cells are plant cells, animal cells, and bacteria cells. The second characteristic of life is a thing's need of materials. Some of the main needs necessary for a living thing include water, minerals, and air or oxygen. When something needs materials, they take what they need to survive. The third charaacteristic of life is when something is homeostatic. This means that living things stay the same internally despite enviornmental changes in the areas in which they live. In many scenarios, living things use alot of energy to stay homeostatic. As humans, we stay homeostatic by keeping our temperature and through excretion. The fourth characteristic of life is when something responds to stimuli. A stimulus is anything that causes living things to react, and response is the reaction to a stimulus. This means that when an object reacts to a stimuli, something is causing it to react. Depending on what the stimulus is, a living thing will respond differently. The two main types of reactions are positive and negative responses. The fifth characteristic of life is when a living thing can reproduce. This means that thing can producd offspring of their own kind. Animals reproduce sexually. However, plants have other options. They can reproduce sexually, asexually, or through cellular division. The sixth characteristic of life is an object's ability to grow. Living things grow from a lower/simpler form to a higher/complex form. It is important to note that not all things grow at the same speed or the same way, or else everything would be the same. The seventh characteristic of life is when something can adapt. When something can adapt, it can make modifications that make an organism suited for a certain way of life. Another thing related very closely to adaptation is evolution, which is the process by which characteristics of species change through time. The eighth and final characteristic of life is an object's ability of respiration. When an object respirates, it is able to release energy stored in chemical bonds of sugars. In humans, cells use oxygen to release the energy stored in food molecules, and CO2 is produced as a waste product. In respiration, there are consumers, who must take in food to consume life. There are also producers, who create their own food.



Figure 1: Animal Cell