Serena

=Log #1:=

3/24/10
Analog and digital signals have a lot of differences. Analog signals are signals that smoothly record numbers and information. Digital signals jump from one number to another. That's why some clocks are called analog clocks and others are called digital clocks. Digital clocks jump from minute to minute, where as analog clock move from number to number in one movement. Semiconductors are elements that conduct heat and electricity better than the nonmetals, but not as well as the metals. Semiconductors can be used in electronic devices as switches. They can also be used to amplify the current. Diodes and transistors have semiconductors inside them. Diodes make the current flow in only one direction. Transistors can act like switches, blocking the current or allowing it to flow.

Electronics would be very useful on Mars. Rovers could use analog signals to record the temperature and climate of Mars. That information could be sent back to a space station and could be turned into digital signals to make storing the info easier. Integrated circuits would also help improve the technology and quality of the Rover and the orbiters. Semiconductors could also be used to control the Rover and how it moves. Electronics are a key part to an expedition in space.

=Log #2:=

Circuits and Currents
Substances that conduct heat and electricity under certain circumstances are called semiconductors. These semiconductors are made up of atoms. Atoms that don't have full energy shells, are more willing to give up electrons and make the electricity flow. In order for the electricity to flow, there has to be a difference in electrical charges so a current will be created. Current is the flow of electrical charges and is measured in Amperes. Voltage is the pressure that pushes the electrons and is measured in Volts. Resistance is what opposes the Voltage and limits how the current flows and is measured in Ohms.

** Figure 1. A Sucessful Circuit **

The current flows in a circuit which is basically is the circle the electrons travel on. The electrons repel themselves and are attracted to the positive terminal of the battery. Because of the repelling and the attraction, they flow around the wire towards the positive terminal. There are two ways a circuit can be connected to a device, in series or in parallel. When a circuit is connected in series there is only one path for the electrons to go on, even if there are multiple devices. Because of this, if one device fails, all of them fail. If the circuit is connected in parallel, each device has its own pathway for the electrons to reach it. This can be thought as a better way to connect a circuit because if one device fails, the rest of them will continue to run.

Figure 2. A Circuit in Parallel **

=Log #3:=

Rockets Through the Ages
Rockets have been around for hundreds of years. The start of rockets dates all the way back to Ancient Greece where the inventor Hero had created a kind of engine that ran on steam. Then the Chinese filled bamboo full of gunpowder and lit them on fire to create explosions. The Chinese also realized that the gunpowder could be used as weapons and eventually produced tubes of gunpowder that could fly through the air powered by its own gas. The Chinese attached a long rod to the primitive rockets to help it fly straight and used them against the Mongols. The Mongols started using these rockets as well and are credited for the spread of rockets to Europe and then eventually America Figure 3. How the Hero Engine Works ** In America a scientist named Robert H. Goddard made a hypothesis that rockets would be powered better by liquid fuel than by solid fuel. This discovery along with Goddard's invention of the gyroscope was a huge step towards modern rocketry. During World War 2, rockets were used mainly for warfare and destruction. In 1957 the Soviet Union launched the Sputnik I, the first satellite. The USA launched their own satellite and then proceeded to form NASA. The rocket has come far in history, and it can only go on to fly farther.


 * Figure 4. The Symbol of the National Aeronautics and Space Administration**

=Rocket Flight Stages Simulation= media type="custom" key="5931055" ** Instructions ** This Scratch animation is a simulation of the different stages in rocket flight. The goal was to get a lander onto Mars through the rocket. To start the simulation, press the green flag picture at the top right-hand corner. To stop the simulation, press the red stop sign. Remember to turn on your volume to hear the sound effects! Enjoy!

=Log #4:=

[[image:snj_rocketphoto2.jpg]]
The parts of the rocket have very different functions and help the rocket fly in different ways. The Nose Cone helps the aerodynamics of the rocket and its pointed shape reduces air resistance. The Body Tube is the main part of the rocket and holds the engine and the recovery system. The Fins and the Launch Lug help the rocket fly straight in the air. The Motor Mount holds the motor in place and the Motor is what produces the push to have the rocket overcome the pull of gravity and fly. The Recovery System helps the rocket land safely once its reached its apogee and the Recovery Wadding protects the Recovery System from the hot motor.

=Log #5:=

The purpose of this experiment was to discover if the mass of a rocket affects how high it flies. When the rocket was on the launch pad, gravity was pulling it down and the ground was pushing up on it just enough so it wouldn't sink into the ground. During liftoff, gravity was still pulling down on the rocket, but the gases that were being produced by the engine provided enough thrust for the rocket to lift off the ground. Eventually all the gases were used up, but the rocket continued to fly upwards, or coast, because of inertia. It was hypothesized that the greater the mass of the rocket was, the lower its apogee would be. This was thought because bigger objects have greater trouble getting off the ground because the pull of gravity on them is greater than the pull of gravity on smaller objects. Because the pull of gravity on the rocket would be stronger, it would also be harder for it to fly higher. This was also thought because bigger rockets would also have a greater inertia, or reluctance to move.



**Graph 1. How the Mass of the Rocket Affects the Apogee​** When weighed, it was discovered that all the rockets weighed in the range of 43 grams to 51 grams. When the rockets were launched they flew anywhere from 119.2 meters high to 70 meters high. It was observed that the lower the mass was, the higher the rocket flies. There was an Inverse Relationship between the mass and the apogee which was seen in Graph 1. This was determined because the numbers went in opposite directions. When the rocket mass went up, the apogee would go down. The highest apogee was 119.2 m, and the rocket was also the rocket that weighed the least at 43 grams. The rocket whose apogee of 70 meters, which was the least high, weighed 44.4 meters. However, this was not the heaviest rocket. The heaviest rocket was an outlier because it weighed 51 grams, but flew 88.5 meters high.

=Log #6:= =28/4/10= =History of Robotics= The history of robotics stretches back to the times of Ancient Greece. One of the first robots know to man was a small metal bird, propelled by steam made by Archytas in 350 BC. Later in 200 BC, the first water clock (like the one shown in Figure 1) was invented which was a great advance from hour glasses. In 1495 Leonardo da Vinci made a suit of armor with mechanisms inside it that caused it to move like a real person. From there, the creations of robots and other devices only expanded. In 1921, the word "robot" is introduced to the world through a Czech writer. Issac Asimov created the Three Laws of Robotics in 1940. Basically the rules state that no robot can't do any action (or lack of action) that results with humans being harmed.



**Figure 1: A Greek Water Clock​** As technology improved, so did the quality of the robots. The Stanford Research Institute developed the first mobile robot to know its own actions, and calls it Shakey. The Stanford Research Institute later creates other famous inventions like the Stanford Arm and the Stanford Cart. Shortly after Shakey, a artifical intelligence program called McHack is created and later goes on to become Big Blue, the chess program that beat the Grand Master Gary Kasparov. In 1994 Marc Thorpe starts the very first Robot Wars in California and in 1996 Honda unveils the first humanoid robot P3, as seen in Figure 2. In 1998 Lego releases the very first Mindstorms program. Finally, in 2004, NASA is able to land the rover Spirit on Mars. Its amazing to see how far robotics has come, and its amazing to think of how far robotics would have gone in another 100 years.


 * Figure 2: the P3 robot**

=Log #7:= =5/5/10= =Cha Cha Slide Dance Challenge= In this challenge, the objective was to get the robot to dance to the Cha Cha Slide. The robot had to be programmed to follow the instructions called out by the DJ using Lego's Mindstorms software. Then the robot was videotaped doing the dance. media type="custom" key="6079263"
 * Video 1: The Robot Doing the Cha Cha Slide**

Figure 1 shows the first part of the code that was used to program the robot. Each block represents a different command. The first block is a movement block. It tells the robot to turn to the left for one rotation at 75 percent power. The second block is also a movement block. This one tells the robot to move forward for one rotation at 75 percent power. These two blocks symbolize the “to the left” directions in the song. The next two blocks are movement blocks as well. The third block tells the robot to reverse for one second at 75 percent power. This is the “bring it back now y’all” command in the song. The fourth block tells the robot to go forward for 0.25 seconds at 75 percent power. This results in a slight jerk to show the “one hop this time” command. The fifth block is a new kind of block, called a wait block. This tells the robot to wait for one second before continuing on. The block after the wait block is another movement block. This one tells the robot to turn to the right for 0.75 seconds at 75 percent power. The next movement block tells the robot to move forward for 0.5 rotations at 75 percent power. These blocks show the “right foot lets stomp” command. The last block in this part of the code is another wait block, telling the robot to wait for one second.

**Figure 1: The First Part of the Code**

Figure 2 is the second part of the code. The first four blocks in this picture are all movement blocks. The first one tells the robot to turn to the left for one rotation at 75 percent power. The second one tells the robot to move forward for 0.5 rotations at 75 power. These blocks show the “left foot lets stomp” directions in the song. The third block tells the robot to move forward for 0.1 rotations at 75 percent power. The last block tells the robot to turn to the left for one rotation at 75 percent power, resulting in a 180 degrees turn. These two blocks are part of the “cha cha now, y’all” commands. Placed around the entire section so far, is a loop which is set to two, which tells the robot to run these instructions twice before moving on. After the loop, is a wait block which tells the robot to wait for two seconds. The next block is a movement block that tells the robot to move forward for 0.25 seconds at 75 percent of power. The following block is also a movement block that tells the robot to reverse for 0.25 seconds at 75 percent power. The loop that’s placed around these two blocks is set at four. This means that these two blocks will be repeated four times resulting in a jerky forward-backward motion which is the first half of the “now it’s time to get funky!” command.


 * Figure 2: The Second Part of the Code **

Figure 3 shows the third and final part of the Cha Cha Dance Challenge code. The first block is a movement block that tells the robot to turn to the left for four rotations at 75 percent power. This causes the robot to spin around and around, which is the second half of the “now it’s time to get funky!” command. Next there is a display block with a smiley face selected. Then there is a wait block set at three seconds. These two blocks make the robot display the robot for three seconds, ending the dance.

**Figure 3: The Last Part of the Code**

=Log #8:= =18/5/10= =The Characteristics of Life= In order for a thing to be considered 'alive' it has to fall into all eight characteristics of life. The first characteristic is that the thing must be made out of cells. Animals, plants and bacteria all have cells in them. A picture of human cell can be seen in Figure 1. The second characteristic is the need of different materials. All living things need water, oxygen and minerals. They take what they need from the environment. The third characteristic is that living things are homeostatic. This means that internally they stay the same, even if their habitat changes. This takes a lot of energy to maintain. An example of homeostasis in humans, is their temperature. The fourth characteristic is having a response to stimulus. Stimulus is anything that causes living things to react. There are two types of reactions. A positive reaction is when the living thing moves toward the stimulus. A negative reaction is when the living thing moves away from the stimulus. Response to stimulus also includes the ability to move from place to place. Even though plants can't do that, they still have reactions to stimulus. The fifth characteristic is the ability to reproduce. There are two ways living things produce offspring of their own kind, sexual and asexual. Sexual reproduction is when there are two parents, asexual is when there is only one parent (this is more common with plants). The sixth characteristic is growth. Every living thing starts as a simple form, then grows into something more complex. However, not everything ends up the same size. The seventh characteristic of life is adaptation. Living things change to suit their way of life. An example of this is how fish have gills to breathe underwater or how birds have hollow bones to make it easier to fly. The final characteristic of life is respiration which is releasing the energy stored in food.


 * Figure 1: A Human Cell**