Kimia

Analog vs. Digital Signals, Transistors, Semiconductors, Diodes, and  Integrated Circuits

Log 1- 3/22/2011

There are many different types of electronics, which all function differently, and serve different purposes. Throughout transmission, an **//analog signal//** remains the same. This means that the signal does not change and is received and then displayed. Analog signals also run smoothly, and do not jump around. Clocks, microwaves, and dial thermometers are some of the things that use analog signals. On the other hand, **//digital signals//** are sampled before they are received. They bounce around quite quickly, going from place to place, and also, not very smoothly. CD players and digital clocks are two things that use digital signals, which move quickly, instead of slowly. **//Semiconductors//** can only partially conduct heat and electricity, which is why they can be used in computers and other electronics. This helps, because too much current won’t be used, and also, when switched off, they can store the energy. Their conductivity can be controlled, and this is done by adding impurities to the semiconductors. Using a semiconductor is the most efficient way to build electrical devices. **//Transistors//** are used to alternate the signal sin circuits. They can make the signals smaller, or amplify them, or just completely shut it off. **//Diodes//** convert AC-altering current, into DC current, which helps when you need a certain type of energy. Because transistors and diodes are large on their own, an **//integrated circuit//** would allow the millions of transistors necessary for a PC, to all fit in a small box (1mm x 1mm). If this wasn’t the case, computers would be greatly larger, and would not be easily portable. (Transistors can work like catalysts)

Throughout early space exploration, operated craft (robots) were used instead of man. This was helpful, and efficient, because less fuel was needed, and life supporting materials, especially oxygen, were not needed. Electrical devices give the capability for data, and information to be sent back and forth between Mars and Earth. Electrical devices would serve a way for communication. In space travel, electrical devices are needed from the start. If there were no electrical devices in space travel, the space shuttle would not even be capable of taking off. Also, rovers are electrical devices, and they are helpful for the planet Mars, in specific, especially because of its harsh climate. True, you could make suits and other electrical devices for humans, and send them up, but it would be easier to build a robot. Also, taking in that it would take two years to get to Mars; if there were humans in a space shuttle On the other hand a rover could get there faster, because there is less to haul. If you were to travel to Mars, electronic devices would be really be the only way of capturing proof of life, if there is any, and reporting it to Earth. The signals in electoral devices would be useful on Mars. Diodes and transistors would keep the rover (or shuttle) in motion, by pushing the current, and blocking and/or allowing the current to pass through specific loads. Lastly, analog signals can be used for recording information because it would work slowly and smoothly.

//Ms. Mc - Very good overview of electronics and how we might use electronic devices on a mission to search for life on Mars. Digital signals likely would be used to store information, however, as they allow for a lot of information to be stored in a small space (i.e., on a compuer hard drive). 10/10 //

=Entry # 2- Rocket History =

3/__/11

The Hero Engine was the first device to use the same basic principals of rocketry. It was created by Hero of Alexandria, in 100 BC. This device functioned in a very basic way. A fire was placed under a kettle, and the heat of the fire vaporized the water, turning it into steam. This steam, then traveled through two tubes into a sphere. This also has two tubes, but they are L-shaped, and they faces outward in opposite directions and on opposite sides. The steam escapes from the inside of the sphere through the two tubes, which cause the sphere to rotate. It is uncertain when the first rocket actually appeared. Many believe that the first ever rockets were mistakes. One accidental discovery the Chinese made was with bamboo sticks, and gunpowder that they usually used for festivals. Sometimes the tubes only got half lit, and that would result in it flying out of the fire. Soon, the Chinese began to experiment with these tubes, and sometimes, attaches the bamboo sticks to arrows. They finally figured out that the tubes could launch on their own, with the pressure from the escaping gas….the first rocket was created. The first public use of rockets was in 1232. This use was during war. At the time, the Mongols and Chinese were at war, and the Chinese used their 'rockets' to push the Mongol's back. The Mongols claimed them to be "arrows of flying fire". These were just a tube capped at one end, and left open at the other, with gunpowder inside. The powder would be ignited, the burning of it created fire, smoke, and gas, which would all escape out of the open end of the tube, which caused a thrust. After the Chinese's defeat of the Mongols, the Mongols, first created their own rockets, and then spread the invention into Europe. In 1898, a Russian schoolteacher; Konstantin Tsiolkovsky proposed a new idea. He decided that they use liquid propellants, and even use rockets for space travel, and not just for celebrations and/or warfare. Tsiolkovsky has been called //The father of modern astronautics.// During the early 20th century, an American; Robert H. Goddard concluded (on top of Tsiolkovsky's idea) that a liquid propellant would function better. On March 16, 1926, Goddard managed to create his (and Tsiolkovsky's) vision. Goddar has been named //The father of modern rocketry.// The Soviet Union announced its launch of an Earth satellite, on October 4, 1957. This satellite was called //Sputnik.// Interestingly...the Soviet Union launched a dog named Laika into space. This dog only survived for seven days. The Explorer I was launched into space a few days after Sputnik, and soon, in October, the US organized a space program; NASA (National Aeronautics and Space Administration). NASA is now an agency with the goal of space exploration that can benefit the entire world. Rockets evolved from Hero of Alexandria's simple Hero Engine to the astonishing International Space Station.

// Ms. Mc - Excellent summary of the history of rocketry and great drawings! Please be sure to include a figure # and title for all drawings/photos. 14.5/15 //

Entry #3: Rocket flight Simulation:

Instructions to run simulation:
 * Make sure your volume is on
 * When you open this page...it'll probably start to randomly play on it's own, so hit the stop sign button.
 * To begin the simulation, click on the green flag
 * Watch and enjoy!!

media type="custom" key="9028138"

Entry #4: Rocket Parts 4/13/11



The **nose cone** directs the air around the rocket and helps it fly straight. The **body tube** is the main structural part of the rocket, and it holds the recovery system, the recovery wadding, motor mount, and the motor itself. The **recovery system** allows the rocket to land slowly and gently, therefore the rocket does not get damaged. The **recovery wadding** ensures that the recovery system does not get burned or damaged by the heat or the gases released by the motor. The **launch lug** guides the rocket, so it will launch straight from the launch pad. The **motor mount** holds the motor in place, and the **motor** is what provides the rocket's thrust. Finally, the **fins** make sure the rocket flies straight.

Ms. Mc: Excellent definitions and great labels. Don't foget to include a figure # with your captions (-1/2). 19.5/20

Entry #5

<span style="color: #5027e7; font-family: 'Arial Black',Gadget,sans-serif; font-size: 130%;">4/17/11

The purpose of this experiment was to see if the mass of a rocket would affect its apogee. When the rocket is at rest on the launch pad, only gravity and the force of the launch pad (which are equal) are acting on the rockets. Because the gravity and the force of the launch pad are equal, the rocket is clearly motionless. At lift off, there is still gravity pulling down on the rocket, although, since the rocket is gradually going into motion, the thrust (which is what is putting it in motion) is greater than the gravity. It was hypothesized that if a rocket is more massive, then it will have a lower apogee because of the law of inertia. The more massive an object is, the more inertia it has, meaning that it takes more force to alter its state of motion. This would cause the apogee of more massive rockets to be lower because the thrust applied by the launch pad was equal for all the rockets. Therefore the less massive rockets had an advantage because the thrust was the same amount a more massive rocket would receive.



The results of this experiment showed that the hypothesis was proven correct. The rockets with a higher mass did not have as high of an apogee as the rockets with a lower mass. The lightest rocket was 41.5 grams, and the heaviest rocket had a mass of 46.9 grams. The rockets in the center of the graph had masses ranging from 39.5 to 43 grams. As seen in Figure 1, the rocket with the most mass on a scale of 41-48 grams flew the highest. That rocket had an apogee of 119 meters. The more mass the rocket had, the lower it flew. Therefore the rocket with the least mass had the highest apogee. There is an indirect relationship between the numbers throughout the data, indicated by the downward trend of the best fit line, also seen in Figure 1. In conclusion, the hypothesis was confirmed because the rocket with an apogee in the middle of the scal at 44.4 grams had the highest apogee. There were several error that may have occurred that could have altered the outcome. First, the rockets were launches on different days, therefore there were different wind gusts. Also, the people measuring with the angle guns may have measured differently. One may have measured from the ground, one may have measured from the top of the rocket.

<span style="color: #000000; font-family: arial,helvetica,sans-serif; font-size: 13px; line-height: 19px;"> entry **#6-** crash course astronomy - questions + answers

** 4/26/11 **

**what is a quark? what types of quarks are there?**

** <span style="font-family: 'Comic Sans MS',cursive; font-size: 120%;">A quark is any group of elementary particles. Quarks are the fundamental. It is known that quarks were formed during the Big Bang. As seen in Figure 1, there are 6 different types of quarks (also known as <span style="font-family: 'Comic Sans MS',cursive;">flavours <span style="font-family: 'Comic Sans MS',cursive; font-size: 120%;">). There are up, down, top, bottom, strange, and charm. **



**what is a galaxy?**

** <span style="font-family: 'Comic Sans MS',cursive; font-size: 120%; line-height: 27px;">When gravity collapses matter, galaxies are formed. Galaxies are gravitational bounds that contain stars, gas, dust, and dark matter. All galaxies orbit its <span style="font-family: 'Comic Sans MS',cursive; line-height: 27px;">centre <span style="font-family: 'Comic Sans MS',cursive; font-size: 120%; line-height: 27px;"> of mass. They are categorized by their shape; elliptical, spiral, or irregular. When galaxies were closer to each other, they collided and merged often, therefore resulting in spiral arms. As seen in Figure 3, the Sun is in the bottom half of the galaxy. **



//Ms. Mc: Good answers, pictures, and captions. Be sure to read over your answers before posting. Quarks are the fundamental what? Galaxies are gravitational bonds (not bounds). (-1/2) 9.5/10//

Entry #7- Extra Credit- XXXXXXXXXX

<span style="font-family: Impact,Charcoal,sans-serif; font-size: 210%;"> Entry # 8- Robot Challenges <span style="color: #800000; font-family: Impact,Charcoal,sans-serif; font-size: 150%;">//5/6/11//

<span style="color: #4623c7; font-family: 'Comic Sans MS',cursive; font-size: 120%; tab-stops: 324.3pt; tabstops: 324.3pt;">**Block 1-** Movement block that tells the robot to move servomotors B and C forward at 75% power for 2.8 seconds
 * Block 2-** Movement block that tells the robot to move servomotors B and C to turn right 180 degrees at 75% power
 * Block 3-** Movement block that tells the robot to move servomotors B and C forward for 1.5 seconds at 75% power
 * Block 4-** Movement block that tells the robot to move servomotors B and C to turn left 180 degrees at 75% power, then brake
 * Block 5-** Movement block that tells the robot to move servomotors B and C at 75% power, forward for 1.5 seconds, then brake.
 * Block 6-** Movement block that tells the robot to move servomotors B and C to turn 1440 degrees at 75% power
 * Block 7-** Sound block that tells the robot to make an applause sound at 75% volume
 * Block 8-** Display block that tells the robot to display a smiley face image on the screen
 * Block 9-** Wait block that tells the robot to wait 1 second.
 * Block 10-** Display block that tells the robot to reset the programing.