Gretchen

3/23/11 – Log Entry #1 - Electronics and Mars Necessities

==== There are many kinds of electronic devices that require electronic signals to receive information. Electronic signals are changes in electric current. There are two types of information-carrying electronic signals, analog signals and digital signals. The information that electronic devices receive can be transformed into sound, images, printed words, and other data. The difference between analog signals and digital signals is that the current which produces analog signals changes smoothly while the current that produces digital signals change in jumps or steps. Most of the devices which use electronic signals are made of many components and electrical circuits. Something that is useful to have in these circuits is a semiconductor. Semiconductors are metalloids and can conduct electricity better than nonmetals, but not as well as metals. The conductivity of semiconductors can be changed through a process called ‘doping’, which is when impurities are added to a semiconductor. A single atom of arsenic in a million silicon atoms can greatly change the conductivity of the silicon. Doping can produce two kinds of semiconductors, n-types and p-types. N-types are ‘doped’ semiconductors with extra electrons, and p-types are ‘doped’ semiconductors with fewer electrons than normal. Different combinations of the two types can act like switches in electrical circuits, which is very helpful because they can control whether electricity flows through the circuit or not. Electronic components that are made of combinations of semiconductor types are called solid-state components, and two common types of those are diodes and transistors. Diodes are components that allow electric current to flow through in only one direction. Because n-type semiconductors give electrons and p-types take electrons, current can flow through in one way but not the other. That is how diodes keep the current going in one direction. Transistors are components that amplify signals in electric circuit. They are also used as electronic switches in circuits – signals can pass through them and allow or disallow current from flowing through them. All solid-state components are parts of electric circuits. Integrated circuits are smaller than regular circuits and can be used in small electric devices, such as personal computers. ==== On a mission to Mars, electronic devices are not only important – they are necessary. Without electronic devices, interplanetary missions would fail. Space shuttles contain many electronic devices that are needed to keep them running properly. Satellites and computers are necessary for keeping in contact with unmanned probes and astronauts. Cameras are needed for surveillance of other planets and of space. Motors and wheels have to be on unmanned probes so they can move around a planet’s landscape and send back pictures and video. When searching for life, cameras are especially important because to find life or possible life-sustaining environments, you need to be able to see the area and look for things like old river beds or minerals in the ground. Electronic devices are the things that make a mission to Mars possible. Without them, there would be no way to even get to Mars at all.

Nice job, transition between the different components! However, no matter how I tried I couldn't find a single error. Nice colors and title!
//Ms. Mc: I agree 100% with Claire! Excellent work! 10/10//

**4/5/11 – Log Entry #2 - Rocket History**

 The earliest appearance of a device that used the principles of rocket flight was a machine called an aeolipile. The aeolipile was invented by a Greek inventor called Hero of Alexandria around 100 B.C. However, the time when the first real rockets were invented is unknown. They first appeared in first-century China. The Chinese filled bamboo tubes with a type of gunpowder made of saltpeter, sulfur and charcoal dust, attached the tubes to arrows, and fired them with bows. The Chinese discovered that the rockets could propel themselves on their own with the power of the gas. The first use of real rockets was in 1232, when the Chinese used it in war against the Mongols. The Chinese had a tube that had one side open filled with gunpowder. The tube was tied to a stick and the gunpowder was ignited. The gas launched the rocket off, and it flew into the sky and exploded  on the enemy.

 **Fig. 1 - A Chinese rocket**

In 1898, a Russian teacher named Konstantin Tsiolkovsky proposed space exploration using rockets. He proposed using a liquid propeller to allow the rockets to be able to travel further when launched. In the early 20th century, an American named Robert Goddard conducted rocket experiments. His earliest experiments were with solid-propellant rockets. He later tried different types of solid fuels and decided that rockets could be propelled much better with liquid propellants. Building a liquid propellant rocket was much harder than building a solid propellant rocket; it necessitated fuel, oxygen and new chambers in the rocket. However, Goddard finally achieved the first successful liquid propelled rocket flight on March 16, 1926. 

**Fig. 2 - a German V-2 missile**

After Goddard’s flight, lots of rocket societies were started around the world. One of these societies, a German group called the Verein fur Raumschiffart, invented the V-2 rocket, which had a large thrust and was used against Britain in World War 2. When Germany was defeated in the war, Allied scientists found unused V-2 rockets and began to study them. On October 4, 1957, the USSR launched the first-ever Earth-orbiting artificial satellite, called Sputnik. They rapidly followed by launching a dog named Laika into space, the first ever living creature to orbit the Earth. A few months later, the US sent up a satellite called Explorer I. In October 1958, NASA was formed. With all of these new inventions, space was opened up as a vast place to explore. It was no longer a mystery to the people of Earth.

// Ms. Mc: Excellent summary of the history of rocketry. Your drawing are great too! I have to disagree with your last statement though as we have just begun to explore outstide our solar system so there is a lot of mystery still to be solved. 15/15 //


 * 4/5/11 - Log Entry #3 - Rocket Flight Simulation**

media type="custom" key="8980290"

To run my project, make sure your volume is turned up. Then press the green flag. If you wish to stop the simulation, press the red button


 * 4/12/11 - Log Entry #4 - Parts of the Rocket**


 * Fig. 1 - Labeled Parts Of A Rocket**

The nose cone of the rocket guides the airflow around the rocket. The cone shape is the most aerodynamically efficient – it allows the rocket to fly through the air easier. The body tube is the main part of the rocket in terms of structure. It contains the recovery system, recovery wadding, motor mount and motor. The recovery system is a device that allows the rover to land safely on Mars and explore. The recovery wadding is an item that protects the recovery system from the heat generated by ignition. The launch lug keeps the rocket straight as it lifts off from the launch pad. The motor mount keeps the rocket motor in place, and the rocket motor powers the rocket’s flight. The fins of the rocket keep the rocket flying straight when it is in flight.

//Ms. Mc: Excellent explanation of the functions of the rocket parts. 20/20//

**4/16/11 - Log Entry #5 – Rocket Launch Lab Write-Up** This experiment had several purposes. One was to observe how rockets launch and fly for our Mission to Mars project. Some of the things that were observed were the forces that act on rockets at different points of their flight. When the rocket is on the launch pad prior to launching, the forces of gravity and of the launch pad are acting on it. As the rocket begins lift-off, the force of air resistance and of thrust from the rocket’s engines begin to act on the rocket. The same forces continue to act on the rocket during the rocket’s powered flight. Then, when the rocket begins coasting and cuts its engines, the only forces acting on it are gravity and air resistance – the rocket’s inertia keeps the rocket moving. Inertia is when an object doesn’t want to change the state of motion it is in. When the rocket reaches its highest point and arcs over towards Mars, the only force acting on it is gravity. Another purpose of the experiment was to find the relationship between the mass of a rocket and the rocket’s apogee (the peak of the rocket’s flight). It was hypothesized that if the mass of the rocket was increased, the apogee of the rocket would be lower because the more mass there is, the more Earth’s gravity pulls it down.

Seven rockets were built, painted, launched and observed. Before being launched, the mass of each rocket was found using triple-beam balances. The heaviest rocket was found to be 44.5 grams, and the lightest rocket was found to be 42.2 grams. When each of the rockets was launched, their apogees were calculated by way of trigonometry. Two measurements of the rocket’s average altitude angle were taken from 100 meters away from the launch site. The two measurements were then averaged. Then the tangent of the average was found and multiplied by 100. That was the method used to find the apogee of the rockets. The highest apogee calculated was 81 feet, while the lowest was calculated to be 53 feet. After the data was collected, it was organized and analyzed. A graph was made showing the relationship between the apogee of the rockets and their masses. The data is shown in graph #1.

The information in graph 1 showed that there was a direct relationship between a rocket’s mass and its apogee. This showed that the apogee of a rocket increased when its mass increased, and the apogee decreased when the mass decreased. It was concluded that when the mass of a rocket was increased, its apogee increased as well. This did not confirm the hypothesis that was created. Examples from the data show this. A rocket with a weight 42.2 grams had an apogee of 53 feet, while a rocket with a weight of 44.1 grams had an apogee of 75 feet. The heaviest rocket, weighing 44.5 grams, also flew the highest with an apogee of 81 feet.This showed that the hypothesis was incorrect. There was one outlier - the second heaviest rocket, weighing 44.4 grams, had an apogee of 55 feet, the second lowest apogee of the seven rockets. The experiment that was conducted was controlled in many places, but in some there were room for error. The range of rocket masses was not large, which may have led to error. The weather conditions also could have caused error. On the days when the rockets were launched, there was wind that may have blown some of the rockets off course slightly. The measurements of the average altitude angles of the rockets may have also been erroneous, because different people measured every rocket. The measurers may have held the measuring instruments differently or have been in different positions to measure the angles. Those were the areas in which the experiment was not necessarily controlled.

A galaxy is a collection of gas and dust that is classified by its shape. A galaxy can be elliptical, spiral or irregular. Galaxies formed in areas of the universe where there was slight unevenness in matter. Gravity collapsed the matter and galaxies were formed. Our solar system is much younger than the Universe. It formed when the Universe was 3 billion years old. No galaxies were formed before 2 billion years after the Big Bang, which was when the Universe was formed. Our solar system is younger than some of the galaxies, and is definitely younger than the Universe.
 * 4/23/11 - Log Entry #6 - Galaxies and the Universe**
 * //Fig. 1 - Galaxy//**

//Ms. Mc: Good answers, however, #2 isn't quite right. Our galax, the Milky Way, formed about 12 billion years ago but our solar system formed about 5 billion years ago (-1). Please be a little more descriptive with your caption titles and be sure to refer to them in your text (-2). 7/10//
 * //Fig. 2 - The Big Bang//**

5/4/11 – Entry #8 - Explanation of Programming Codes




 * This program tells the robot to perform the “On the Edge” challenge. The first block is a timing block activating the sound sensor attached to port 2 and telling the robot to wait until it receives a sound command to do the second block. The robot didn't start moving until we said 'go'. The second block is a motion block activating the servomotors that are connected to ports C and B and telling the robot to move forward in a straight line at 75% power for an undefined amount of time. The third block is a timing block activating the light sensor attached to port 3 and telling the robot to wait until the light sensor registers a change in light to do the fourth block. The fourth block is a motion block telling the robot to stop. The robot went forward until it detected a change in light and then stopped. The fifth block is a sound block telling the robot to play a recorded sound at volume 3. The robot played the sound (a voice saying 'watch out').**