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Electrics: Log Entry #1 3/23/2011 An analog signal is a signal that varies smoothly in time. In an analog signal the electric current increases or decreases smoothly in time. A digital signal does not vary smoothly, but changes in jumps or steps. A digital signal can be represented by a series of numbers. So, the difference is that an analog signal varies smoothly and a digital signal varies in jumps and steps. A semiconductor is an element that is a poorer conductor of electricity than metals but a better conductor than nonmetals. The two types of semi-conductors can be put together to from electronic components that can control the flow of electric current in a circuit. Other combinations can form components that can increase, or amplify the change in an electric current or voltage. Diodes are useful for converting alternating current to direct current. A diode allows only the current in one direction through. A transistor is used to amplify signals in an electric circuit and is also used as an electronic switch. An integrated circuit contains large numbers of interconnected components and is made from a single chip of semiconductor material.

It is very important to have electronic deises when going to Mars because they help with almost everything and if you fail then they won’t. They can tell you where to go and help you basically survive. Since our technology isn’t advanced enough to do that on our own, we have to have the help of robots and electronic devices to guide us. In the coming years, electronic devices are going to be key in the development of our civilization.

//Ms. Mc: Good overview of electronics. Don't forget to start with a topic sentence. Your discussion of how we might use electronic devices on our mission to Mars is a little sparse as far as the specific devices we might use. For example, computers, navigation systems, communication systems, satellites, cameras, etc. 8.5/10//

4/5/11. Log Entry #2. The History of Rockets Nobody knows when the first true rocket appeared, but there are many stories that help lead us to the answer. Hero of Alexandria, a Greek inventor, was the first to successfully employ the principles of rocket flight. He did this in 100 B.C., he mounted a sphere on top of a water kettle. Below the kettle, a fire turned the water into steam, and the gas traveled through pipes to the sphere. On opposite sides of the sphere, two L-shaped tubes allowed gas to escape from the sphere, and gave a thrust to the sphere. In the first century A.D., the Chinese began experimenting with gunpowder-filled tubes. At some point in the process, they attached bamboo tubes to the arrows and launched them with bows. They soon discovered that the gunpowder tubes could launch themselves just by the power produced from the escaping gas. Thus, the first rocket was born. In the 1220s, the Mongols went to war with the Chinese, in the battle of Kai-Keng. During the battle, the Mongols were repelled by a barrage of “arrows of flying fire.” These arrows were a simple form of a solid-propellant rocket. After the war was over, the Mongols produced their own rockets and were thought to be responsible for the spread of rockets in Europe. All through the 13th to 15th centuries there were reports of rocket experiments happening across Europe. In this time, all rockets were used for fireworks and/or warfare. Early in the 20th century, an American, Robert H. Goddard, conducted practical experiments in rocketry. He was trying to achieve higher altitudes than were possible for lighter-than-air balloons. He started to experiment with solid-propellant rockets. In 1915, Goddard started to experiment with other types of solid fuels and was later convinced that a rocket could be propelled better by liquid fuel. Although it was much more difficult to build this kind of rocket, he achieved the first successful flight with liquid-propelled rockets on March 16, 1926. His experiments with liquid-propelled rockets continued for years, as the rockets flew higher and became bigger. For his achievements, he has been called the Father of Modern Rocketry. During World War II, the Germans developed a rocket called the V-2. It was used on London to destroy blocks at a time. It was never successful because by the time it was used the war was almost over. After the fall of Germany, many of the unused v-2s were captured by allies. German rocket scientist moved to the US and the Soviet Union. Both the US and the Soviet Union later realized the potential of rocketry as a military weapon and started experimenting with medium and long range intercontinental ballistic missiles. These became the starting points of Space Programs. On October 4, 1957, the world was stunned by the news of an Earth-orbiting artificial satellite launched by the Soviets. Called Sputnik I, the satellite was the successful entry in a race for space between the two superpower nations. A few months after, the United States launched its own satellite into space. Later on, the United States started NASA, which became a civilian agency with the goal of peaceful exploration of space for the benefit of mankind. Soon, many people and machines were being launched into space. Astronauts orbited the moon and later landed on the moon. Rocketry got very advance from the simplest rocket to one flying to the moon. Rockets have majorly evolved and will keep evolving as long as we are on this planet.

//Ms. Mc: Good summary of the history of rocketry. It's important to include specific dates when discussing history. Your drawings were too similar to add to your discussion. Please include "Figure #_" in your captions and insert your drawings/photos in your text when you discuss them as opposed to the end. 13.5/15.//

4/4/11, Mission to Mars: Log Entry #3 1. Turn on your sound 2. Click the green flag 3. Watch the video!!!!!

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4/13/11, Part of a Rocket: Log entry #4

The rocket’s nose cone helps guide airflow around the rocket. The body tube is the main structural part of the rocket and holds the recovery system inside. The recovery system is designed to help get the rocket back safely and intact for more use. The recovery wadding protects the recovery system from the heat at lift off. The launch lug guides the rocket straight off the launch pad. The fins help the rocket fly straight once it is in flight. The motor mount holds the motor in place. The rocket motor is a safe, non-reusable motor.

// Ms Mc: Good labels and definitions. What is the recovery system? (-1/2). What does the motor do? (-1/2). 19/20 //

4/17/11. Log Entry #5. Rocket Launch Experiment

The purpose of the experiment was to find out if the mass of the rocket would affect its apogee height. Aside from mass, there are other forces that could have affected the rocket too. Gravity is the force that attracts everything towards the center of the earth because the mass of the earth is greater than anything on Earth. Gravity doesn’t help the rocket fly because it is pulling it back to the ground. Air Resistance has a small part in keeping the rocket from flying. Air resistance goes opposite of the force that keeps an object moving. The thrust from the rocket pushes it off of the launch pad into the air. The force of the launch pad is equal to the force of gravity because of Newton’s third law, “Every action has an equal and opposite reaction”. During lift off, the thrust has to be greater than gravity and air resistance because the rockets fly’s up. If gravity and air resistance equaled the rockets thrust, the rocket would go nowhere. During powered flight, the rocket’s thrust is greater than gravity and air resistance. During coasting, the rocket has no thrust and is traveling because of its inertia gained during powered flight. At apogee, the rocket’s inertia no longer has any power, so air resistance and gravity take over and cause the rocket to go back to the ground. It was hypothesized that there is a perfect mass for maximum flight. If the rocket weighs more, it won’t go as high, and if it weighs less it won’t go as high either.

 In graph #1, the Rocket Mass has a range of 42.5g to 45.4g, which is a 2.9g difference. In the graph, anything lighter than 44.5g doesn’t go as high and anything that weighs more also doesn’t go as high. So, for maximum height, the rocket needs to weigh around 44.5g. Also in graph #1, the Rocket Apogee has a range of 61m to 93m, which is a difference of 32m. In the graph, the shortest apogee, 61 meters, is also the lightest, but the highest apogee doesn’t weight the most. In graph #1, there is no relationship between the independent and dependent variables. If you were to increase or decrease the mass of the rocket, its apogee wouldn’t necessarily change the same as the mass, so it can’t be direct. If you were to decrease or increase the mass of the rocket, its apogee wouldn’t necessarily do the opposite of what you did to the mass. The change in the mass of the rocket and its apogee are not related. Therefore, it has no relationship.

In conclusion, the hypothesis was confirmed. In the data, the perfect weight was 44.5g. If the rocket weighed more than that, it wouldn’t go as high. If the rocket weighed less than that, it also wouldn’t go as high. In this experiment, there were a lot of errors that could have affected the outcome. Since there was a small sample size, there wasn’t a lot of data to compare. The independent variable (mass of the rocket) didn’t change very much, so we couldn’t know what happens with lighter and heavier rockets. The wind and temperature varied between the two days of the launch. The wind could have slowed the rockets climb and the temperature can also have an effect on the rocket. Since the angle gun measurers were different every time, the measurements are likely to be off in some aspects. Although there were numerous known errors in the experiment, the data still corresponds to what was hypothesized.

Log Entry #6. 4/25/2011. Quarks and Galaxies

A quark is a particle that is found in protons and neutrons. Quarks are weird because they have fractional charge unlike protons or electrons. The six types of quarks are up, down, charm, strange, top and bottom. Up and down quarks have the lowest masses of all quarks. The heavier quarks rapidly change into up and down quarks due to particle decay. An up quark has a charge of 2/3 while a down quark has a charge of -1/3. A proton contains two up quarks and a down quark, while a neutron contains two down quarks and an up quark (as seen in figure 1) . Galaxies are made up of stars, gas and dust. Galaxies might be five times as big as we see them because of the dark matter that we can’t see that is around them. Galaxies are classed according to their shape: elliptical, spiral or irregular. When galaxies merge they cause spiral arms. Galaxies formed about two billion years after the big band, when gravity collapsed the matter and galaxies formed. The Milky Way (our galaxy) formed three billion years after the big bang, and is a spiral galaxy. At the center of our galaxy there is a giant black hole. The Milky Way is 100,000 light years side-to-side.

Ms. Mc: Good answers and pictures. Your caption for Fig. 1 isn't quite right. It shows the 6 types of quarks; protons and neutrons only have up and down quarks (-1/2). When was the Big Bang? (-1/2) Spelling error: "big band" should be Big Bang. (-1/2). 8.5/10

Log Entry #8. 5/5/2011. Block Explanation.

Challenge #3 - I programed the robot to move forwad unitl it detected the blue tape on the edge of the table. Once the robot detected the tape, i programed it to stop before going over the edge of the table and the robot says "watch out!".

Block 1- a movement block that tells the robot to activate servomotors C and B, so it moves forward infinitely at 75% power. Block 2- A wait for block that tells the robot to wait for the light sensor that is connected to port 3 to sense light more than 41 units. Block 3 – A movement block that tells the robot to activate servomotors C and B, so it stops once the light is detected. Block 4 – a sound block that tells the robot to play the sound file, “watch out” at 75% volume once.