Arnav

3/22/11

Analog and Digital Signals, Semiconductors, Diodes, Transistors, and Integrated Circuits.
Analog signals are continous, however digital signals are not continous. Analog signals are continously varying and digital signals and based on 0's and 1's. Transistors are used everywhere as they are the basic part of your electronic devices. A diode is used to control current flow in a circuit. A diode has high resistance to change flow in one direction and a very low resistance to change flow in the opposite direction. If you use conductors instead of semiconductors, you will have no control over the voltage/electrical energy of your power source.An integrated circuit is a tiny electronic circuit used to perform a specific electronic function.

Electronic devices would be very important where the goal is to travel to Mars. First off, we would need a rocket to fly up to Mars, and rockets are modern technology, and have many electronic devices inside them. To search for life, they might have to take soil samples, and to take the soil samples they will need electronic devices that can analyze the soil. They also need lots of technology to give whatever is going to Mars the ability to move. Making a probe to go to Mars will need lots of electronic devices, so that it can move, and it also needs many devices to let it do all the functions that it will need to do in space. There are also many other components, such as computers so that the probe can send back info to earth. These are just some reasons that electronic devices would be important to find out if there is life on Mars.

// Ms. Mc: I like your ideas for how we would use electronic devices on our mission to search for life on Mars. Your first paragraph needed more explantion, however, specifically about what transistors and semiconductors are used for. Please include the entry # in your title. 8.5/10 //

=Rocketry Simulation to Mars:= =be sure to turn your volume up!= media type="custom" key="8956622" ==

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**4/5/11 Entry Prompt 2**
The history of rockets can go far back, and many chances of making rockets failed because a sufficient engine was required. In 100 B.C. a greek man used steam as a main fuel source, and created the hero engine. The Chinese also tried experimenting with gunpowder filled tubes and tried turning the tubes into a rocket. In 1232 the first rockets were used, when the Chinese were at war with the Mongols. The Chinese would shoot fire arrows out of rockets towards the Mongols. A monk in England improved forms of gunpowder that increased the range of the rockets. Another man in France found that more accurate flights could be achieved by launching the rockets through tubes. In 1898 a Russian explorer proposed the idea of sending a rocket through space. Soon the v2 was created, and it was so strong it could devastate full city blocks. These events started rocketry and helped the creation of modern rockets. In 1957, the world was stunned with Earth released a satellite into space, as this was the first manmade thing that was ever sent into space. Soon, many people and machines were being sent into space, including rockets. The satellites helped scientists see the world and helped people know when was the perfect time to send rockets into space, by knowing the weather, etc. Sending animals into space has also helped people on Earth know how much oxygen is required for how long, and what items would be required for someone to go to space == =Image 1. A picture of the Hero engine, a steam powered engine. =

Image 2. A Sketch of a Rocket

//Ms. Mc: Good general summary of the history of rocketry. It is important to include the names of the scientists and dates when discussing history. Your second diagram was not very beneficial to your discussion. In your captions, you do not need to use the words "sketch" or "picture" -- just give the title. Please use Figure # for drawings and photos. 12/15//

Log Entry Prompt 4 //Arnav G.// //4/13/11//

Our model rockets required many parts to make sure that we could safely launch and land them. On the top of the rocket there was the nose cone, which guided the air that flowed around the rocket. The body tube was the frame of the rocket, which is usually a strong paper tube. The recovery system, inside the rocket, is the device used to get the rocket back down to the ground safely and intact after being launched. The recovery system helps land it in such good condition that you can launch the rocket again. The recovery wadding, which is also inside, protects the recovery system from hot ejection charge gases. The launch lug, on the side of the rocket, guides the rocket off the launch pad. The fins, on the bottom sides of the rocket, keep the rocket flying straight. The motor mount, inside of the rocket, is used to hold the rocket motor in its place. Lastly, the rocket motor is a non-reusable motor for the rocket that has to be replaced each time you launch the rocket. // Ms. Mc: Much better on the rewrite. Don't forget to include a figure # and title and a title for your entry (-1). Original score was 9/20 + 5 point (10 rewrtie points/2 for half credit) = 14/20. //

=Entry Log= =4/17/2011= =Arnav G.=   On Wednesday April 13th and Thursday April 14th, many rockets made by students at Cary Academy were launched into the air. The purpose these rockets were launched was so that the students could learn how to use trigonometry to calculate the apogee, or the peak, of the flight. This was part of the Rocketry Unit going on in the Science Class of the Seventh Grade at Cary Academy. These rockets were powered on gunpowder and had been made by the students over a time period of a week and a half. The students had been eager to launch the rockets and this was finally done after all of the students had finished painting their rockets. The apogee, the highest point of the flight, was measured using trigonometry and angle guns that measured the apogee from 100 meters away from the launch pad. The 7 rockets all weighed almost the same, however their apogees varied. There were forces acting upon the rocket, such as thrust, air resistance, and gravity. There was also inertia, lift-off and powered flight. Gravity and air resistance were pulling the rocket down, while the thrust was pushing it upwards. The gravity and air resistance acting on the rocket changed based on the weight of the rocket. Inertia is the force that made the rocket stay in motion because it was already in motion. Inertia was in effect when the rocket was coasting, flying without the engines on, because the rocket kept moving due to inertia. Lift-off was when the engine was ignited, giving the rocket the thrust to go upwards. The powered flight was when the engine was still on while the rocket was moving upwards. It was hypothesized that if the rocket weighs more, then the force of gravity acting upon the rocket will be more and the rocket won’t go as high, because the heavier an object, the faster it falls and if the rocket is heavier, more thrust would be required to push the rocket upwards. The apogee was the highest point of the flight. 

the higher it will go, and thus the hypothesis made was not correct.
Arnav G. Log Entry Number 6 5/15/2011

Figure 1. The Milky Way Galaxy

A galaxy is a system of millions or billions of stars, gas and dust held together by its own gravity. Galaxies differ greatly in size. Some contain as few as a hundred million stars, but the biggest have more than a trillion stars. Galaxies also vary in shape. Astronomers have classified galaxies into three main types based on their shape. These are - spiral galaxies, elliptical galaxies and irregular galaxies. Most large galaxies seem to have supermassive black holes at their centers. Our galaxy, the Milky Way, shown in Figure 1, is a spiral galaxy and it is 100,000 light years in diameter. The Milky Way is just one of about 100 billion galaxies in the universe.



Figure 2. How the Big Bang may have looked.

All of the galaxies formed right after the Big Bang, when matter started clumping together. The Big Bang was a moment in time when the universe started to expand out of an extremely hot, dense state. The Big Bang may have looked like Figure 2. Astronomers have calculated that this event happened about 14 billion years ago. Immediately after the Big Bang, the universe was incredibly dense and hot – much hotter than the core of the sun. Matter and energy behaved differently at that time than they do under the current conditions. Scientists have found that the earliest stages in the universe’s development occurred in fractions of a second. However, it took about 300,000 years for the first elements to form. Stars, planets, and galaxies began to appear within the next billion years.



Figure 3. What the catastrophic collision between the Space Body and the Earth may have looked like.

Scientists have observed that both the Earth and the Moon have similar structures and are made of similar materials. A widely accepted theory about Moon’s origin involves a giant collision theory. Figure 3 shows how the collision may have looked like. According to this theory the Earth was hit by a smaller space body. The energy of the collision threw material out, away from Earth. Bits of material from the crusts and mantles of both bodies went into orbit around the new Earth. Much of this orbiting material clumped together and became the Moon. The pull of gravity keeps the Moon, Earth’s natural satellite, in orbit around Earth. //Ms. Mc: Much better with the rewrite, Arnav! Since you answered three quetions instead of the required two, I will give you full credit for this assignment. 10/10//

**Log Entry Prompt 8. ** **Date: 5/12/2011 ** **Science Class Period 2. ** **Arnav G. **
 * Title of Challenge: Driving Course Challenge. **

The purpose of this challenge was for the robot to follow a track marked on the floor. The challenge consisted of the robot going forward, making a right turn, going forward again, making a left turn, and then making two full rotations. The robots were programmed to follow the track using the Lego Mindstorms EDU NXT programming software.

Picture 5. The code programmed to make the NXT Robot perform the challenge.

Block 1- A movement block that tells the robot to activate servomotors C and B so it moves forward for 2.25 seconds at 75% power and then brakes. Robot moves forward about 40 centimeters at a fast speed.

Block 2- A movement block that tells the robot to activate servomotors C and B so it makes a 190 degree right turn at 50% power and then brakes. Robot makes about a 90 degree right turn.

Block 3 - A movement block that tells the robot to activate servomotors C and B so it moves forward for 1.19 seconds at 75% power and then brakes. Robot moves forward about 15 centimeters at a fast speed.

Block 4 – A movement block that tells the robot to activate servomotors C and B so it makes a 190 degree left turn at 50% power and then brakes. Robot makes about a 90 degree left turn.

Block 5- A movement block that tells the robot to activate servomotors C and B so it moves backwards for .87 seconds at 75% power and then brakes. Robot goes backwards for about 20 centimeters.

Block 6- A movement block that tells the robot to activate servomotors C and B so it makes two full rotations (1390 degree duration) at 50% power and then brakes. The robot makes 2 rotations.

Block 7- A sound block that tells the robot to play “Applause” at 75% volume. Robot makes a clapping noise.

Block 8- A display block that tells the robot to display “Smile01” on its screen after the applause from Block 7. Robot displays a smiley face on the screen.

Block 9 –A waiting block that tells the robot to wait and keep displaying “Smile01” for 3 more seconds. Robot keeps displaying smiley face for 3 more seconds.

Block 10- A display block that tells the robot to reset the display screen. Screen resets back to how it was before the challenge.