ELECTRIC MOTORS

WHAT ARE THEY?

An electric motor, in its most basic definition, is a device that converts electrical energy to mechanical energy. Most electric motors operate off of Ampere's law, which was discovered in 1820 by Andre-Marie Ampere and states that a wire carrying an electric current produces a magnetic fields around itself. The interaction between the motor's magnetic field and winding currents generates the power for which will cause movement. As an electrical current is sent through the motor, a magnetic field is created around the wire. Since the loop itself has also become a magnet, one side will be attracted to the north pole (of the surrounding magnet) while the other end will be attracted to the south. Thus, causing the loop to rotate.

ELECTRIC MOTOR

AMPERE'S LAW

HISTORY

With the invention of the battery in 1800 by Allessandro Volta, the generation of a magnetic field from an  electric current by Hans Christian Oersted in 1820, as well as the electromagnet in 1825 by William Sturgeon, the foundation for an electric motor was set. The basis of a motor was first demonstrated through British scientist, Michael Faraday's, experiment in 1821. Faraday placed a permanent magnet on a free-hanging wire that had been dipped into a pool of mercury Once an electrical current passed through the wire, the wire had begun to rotate around the magnet, illustrating a closed circular magnetic field around the wire. The following year, Barlow's wheel, built by Englishman Peter Barlow, became the first rotating device driven by electromagnetism. After numerous in vain attempts in trying to create an electric motor, German scientist Prussian Moritz Jacobi succeeded in creating the first real rotating electric motor. Following several more advancements, American scientist Thomas Davenport had been granted the first patent for an electric motor.

BARLOW'S WHEEL

ELECTRIC MOTOR (PRUSSIAN MORITZ JACOBI)

DC MOTORS vs. AC MOTORS

The direction of current flow is the fundamental difference between direct, DC, and alternating, AC, motors. In an alternating current, the direction of current flow changes back and forth at a rapid and constant rate. Current flows in AC motors initially travel in one direction through the wire loop and then reverse itself 1/60 of a second later. This attraction change from north to south pole occurs about every 1/60 of a second. Magnetic field changes are correspondent to current changes, therefore, the side of the loop that had been previously attracted to the south pole is now attracted to the north, and vice versa. Consequently, the loop receives another "kick", which twists it around its axis and helps continue the rotation.

ALTERNATING CURRENT MOTOR

On the other hand, electric currents in DC motors always move in the same direction and due to this, the magnetic field will constantly point in the same direction, causing DC motors to stop their rotation after only half of a revolution. In order to solve this problem, the wire coming from the DC power source is attached to a split-ring commutator, a metal ring cut in half. Once the current begins to flow, it travels out of the battery, through the wire, and into one side of the commutator. The current then flows into the wire loop, producing a magnetic field. As the loop rotates, it takes the commutator with it. Once half of a revolution is completed, the current reaches the empty space and then travels onto the second half of commutator. As a result, the current starts to flow in the opposite direction, traveling through the loop and reversing the magnetic field. With the help of the split-ring commutator, a DC motor can be altered into an AC motor.

DIRECT CURRENT MOTOR

PARTS OF AN ELECTRIC MOTOR

Rotor: In an electric motor, rotors are the moving parts, which turn the shafts to deliver mechanical power. Typically, rotors have conductors laid onto it to help carry currents that interact with the magnetic field and power the shaft

Stator: Stators are the stationary part of a motor's circuit. Usually containing windings or a permanent magnet, the core of a stator is comprised of laminations. Laminations, really thin sheets of metal, are used to help reduce energy losses that would occur if a solid core was used.

Air gap: The air gap is located between the rotor and stator and is generally as small as possible, which would reduce the negative effect on the motor's performance.

Windings: Windings in an electric motor are the wires that are laid in coils. Usually wrapped around a laminated magnetic core, windings help to create magnetic poles when a current is sent through it.

Commutator: A commutator is a mechanism used to switch the input of most DC motors, consisting of slip ring segments that are insulated from each other as well as from the motor's shaft.

MY MOTOR

While building my motor, I ran into several problems

1) Though the current flowed like it was suppose to, resulting in sparks at the brushes, the motor was not able to turn. In order to solve this problem, I needed to build a new armature. Once the second armature was put into use, the motor was able to turn.

2) During my first attempt of creating the coil, I realized that many of the wires crossed with the others. To solve this, I put a layer of duct tape between each wrapping to act as a buffer and prevent crossings between wires.

3) Once I had been able to get my motor running, I saw that after several seconds, the shaft would slide away and the brushes would lose contact with the terminal, causing the motor to stop. I used my leftover single-strand wire to solve this problem. By twisting the wire around the metal rod, I was able to create a miniature spring clamp collar clip, which was able to hold the rod in place and prevent any movement. In addition, I extended the length of the terminal so that the brushes would have more room to make contact with the brushes.

4) When wrapping the magnet wire to create the armature for my motor, I realized that the way in which I wrapped the wire resulted in multiple crossings. To help reduce the number of crossings, I wrapped only one layer of magnet wire. I started from the end of one rod and wrapped all the way to the other end. I then took the two ends and brought them to the terminal, therefore creating a circuit.

CREATION

       

             STEP 1: Drill in "L" brackets to hold metal rod

          

           STEP 2: Drill in "L" brackets to hold brushes

STEP 3: Wrap tape around rod to create terminal 

  

STEP 4: Tape metal rods together to form armature

STEP 5: Wrap metal rods w/ magnet wire to allow current flow

STEP 6: Wrap "L" brackets w/ single strand wire to create coil

 

STEP 7: Tape coil on baseboard (place armature between brackets)

STEP 8: Wrap terminal in tin foil and add brushes (to create circuit)

STEP 9: Wrap tape around rod to create holder for thread)

THE FINISHED PRODUCT

ROBOTICS

WHAT IS IT?
        First introduced by the famous science fiction writer, Isaac Asimov, in 1941, the term robotics refers to the the branch of technology that deals with design, construction, operation, and application of robots, being one of many branches of artificial intelligence. As mentioned in his book I, Robot, Asimov explains the three laws of robotics. First, a robot may not injure a human being, or, through inaction, allow a human being come to harm. Second, a robot must obey the orders given to it except where orders will violate the First Law. Third, a robot must protect its own existence as long as such protection does not conflict with the First or Second Law.
        Robots, in particular, are programmable mechanical devices which can perform tasks, as well as interact with its environment, without the aid of humans. The word derives from the Czech, robota, which can be loosely translated to "compulsive servitude". The term was first coined in 1921 by Czech playwright Karel Capek, who later composed "Rossum's Universal Robots" regarding manufactured human-like servant slaves and their struggle for freedom. It is the science and technology behind all of this, which provides the most accurate and complete definition of robotics.

                                                        

PARTS OF A ROBOT
The main parts composing such robots are the body/frame, control system, manipulators, and drivetrain.

• BODY/FRAME- Ideally, the body/frame provides structure for the robot. Although most people are familiar/comfortable with human-sized and shaped robots often depicted in movies, robot bodies can be of any shape or size. The tend to actually look nothing like humans; being designed for function and not appearance. 

• CONTROL SYSTEM- Equivalent to the central nervous system of a human, the control system's main function is to coordinate/control all aspects of the robot. Sensors provide feedback based on a robot's surroundings , which are then transmitted to the Central Processing Unit (CPU). The CPU filters this received information through the programming and then makes decisions based on logic. The same can be done with other varieties of inputs or even human commands. 

• MANIPULATORS- In order to fulfill their main purpose, it is essential for the majority of robots to be able to interact with their environment and world around them. For instance, they may be required to move/rearrange objects from their initial environments without the help of human operators. However, manipualtors are not integral to a robot and one can exist without such manipulators.

• DRIVE TRAIN- Although some robots are able to perform given tasks in one location, most are required to move from place to place. To be able to get from Point A to Point B, robots need a drivetrain, which consist of a powered method of mobility. For humanoid-styled, this is legs, and for others, the drivetrain is typically a wheeled solution. 

ROBOTS GO TO WAR

        As their peripheral equipment become more sophisticated, reliable, and miniaturized, robots have become increasingly utilized for military and law enforcement purposes. Mobile robots have already begun to play an important role in the military, from patrol to dealing with potential explosives. With suitable sensors and cameras to perform different missions, these mobile robots are operated remotely for surveillance patrol and relay back video images to an operator. The mobile robotic platform is attached to a rectangular box with electronic equipment. The platform moves on wheels/tacks and is extracts most of its energy off batteries. Through reading sensors, Communication equipment and sensors detect images, sounds, gases, and other hazards, which are then relayed back to the operator.

       In addition, mobile robots are able to neutralize/detonate suspicious objects that may explode. The platform has a robotic arm which can pick up explosives or suspected hazards in military or civilian settings. Instead of having people get close to hazards or explosive objects, robots are used. If the operator concludes that the object might explode, the robot could neutralize it by shooting to detonate it. Furthermore, mobile robotics can assist military personnel in transporting equipment in the field. The robot acts like a pack mule, carrying large amounts of supplies, especially heavy, burdening loads. In this case, mobile robots are extremely useful due to their ability to navigate across a variety of uneven terrains. Whether it be regular-shaped obstacles, such as stairs, or unspecified shapes, such as rocks, downed trees and other miscellaneous objects, most are able to successfully maneuver due to their design of wheels/tracks.

TECHNOLOGICAL SINGULARITY

WHAT IS IT?

           The technological singularity hypothesis is a prediction in which accelerating advances in technology will cause a runaway effect through which artificial intelligence will exceed the human capacity, thus changing or even ending civilization, in an event called the singularity. This term, "technological singularity" was originally composed by Vernor Vinge and portrays a time after which our technological creations exceed the power of human brains. The main idea behind this singularity is Kruzweil's Law.  When the time comes where intelligent can create more intelligent at such rapid speeds, we will enter an era where technological advances move at such rate unimaginable to the human mind.

WHEN WILL IT HAPPEN?

          Many writers link the development of a singularity to exponential growth in several technologies. Moore's Law being the most prominent example, stating the number of transistors that can be placed on an integrated circuit doubles every two years. With technological advances moving at the fastest pace we've ever seen, most writers hypothesize a singularity sometime during the 21st century. According to Ray Kurzweil, computers as powerful as the human brain will begin to make their appearance around the year 2020. Moreover, the emergence of artificial intelligence, as Kurzweil believes, will come about sometime around 2029. And with that, humans will have reversed-engineered the brain. With this significant discovery of artificial intelligence, humans would be able to further explore many others ideas such as mind uploading.

CODING 

WHAT IS IT?
              
              In its most basic and simplest definition, coding is telling a computer what you want it to do, through the typing of step-by-step commands for the computer to follow. For many people, mastering code is considered similar, if not the same, as learning a foreign language. There are multiple languages of code each created with its distinct purpose. For instance, C, a "low level" but fast programming language is best for anything that is graphically intensive, such as games. Others include Javascript, which was specifically designed for dealing with the Internet, and Perl, a multi-function language, often referred to as the "swiss army knife" of programming.

WHY IS IT IMPORTANT?

               Code dominants our digital world. Every website, computer program, calculator, and even microwave relies on code to operate. This makes coding the foundation of the uprising digital age, and the coders are the builders. Even jobs not directly linked to the field of computer science, such as banking, medicine and journalism, will begin to require a need for basic understandings of coding and programming. As Linda Liukas, co-founder of the coding workshop Rail Girls, states "Our kids should learn how to bend, join, break, and combine code in a way it wasn't designed to. It's a whole generation of kids that will use code like our generation used words." Overall, coding will become the language of a very soon future. 

MUSE (MINING AND UNDERSTANDING SOFTWARE ENCLAVES)

              Although writing code is one way for humans to instruct computers, it may not be the ideal path. With computers still only accepting commands in their own language and programming languages growing progressively sophisticated, only a small percent of the population is able to communicate with computers. Fortunately, new technology will begin to turn coding into a completely useless form of instructions. One illustration of such idea has been developed by the Defense Advanced Research Projects Agency (DARPA), our nation's military science lab. DARPA has begun to launch a program called MUSE (Mining and Understanding Software Enclaves. The first step of MUSE is to collect all of the world's open-source software, containing billions of lines of codes, and arrange them into a giant database. This collection of codes will be able to perform almost any task and MUSE will tag all code, making it easy to find and assemble the necessary lines of code. The result, ideally, would be that one is able to program a computer without any knowledge or background in programming languages. However, this new population of programmers will require good higher-level design thinking in order to clearly explain the computer's task. MUSE still needs a few years before springing to life, but it sets forth the development of non-coding programming.

Catapult Project

HISTORY OF CATAPULT

         

Catapults have been an essential part of warfare since the middle ages, with various types having been used by the Greeks, Romans, and Chinese. Early prototypes were attempts to increase the range and power of a crossbow. The first documented was the use of a mechanical firing catapult (early Ballista) in 399 BC by Diodorus Siculus, a Greek historian. Modern catapults made theirs appearance in Europe around the Middle Ages during the Siege of Dover in 1216 (the French crossed the Channel and were the first to use catapults on English soil). With war being widespread throughout all of Europe, catapults became an important part of war, for they were able to launch projectiles (including human bodies) at city walls, to destroy their protection, or over them to completely devastate a city. All in all catapults were in use until around 885-886 AD when newer technology rendered them useless. During their reign as a warfare powerhouse, three main types of catapults were in use.

     Ballista: The Ballista is basically a giant crossbow and the earliest of all catapults. Believed to have been invented by the Greeks and then later adapted by the Romans, the Ballista consisted of two wood arms attached to a piece of rope (usually human hair or animal sinew). The rope was attached to a winch and once pulled back, cause the bending of the arm. The Ballista could shoot an arrow with deadly accuracy, however, it lacked power compared to the others. Additionally, the springald was basically a smaller version of the Ballista, mainly used for antipersonnel reasons.    

Mangonel: Invented by the Romans in 400 BC, the Mangonel is what people think when thy think of a catapult. The catapult has a long wooden arm attached to a bucket/container with a rope attached to the end. From a 90 degree angle, the arm is pulled back to build tension and store energy in the rope and arm. Once released, the arm shoots back into the original position, but the inertia of the projectile causes it to continue moving forward. The Mangonel shot objects in an overhead arc and was capable of launching up to 1,300 ft. The Onager, a type of Mangonel, had its name derived from the Latin word "onagros" meaning wild ass, since the motion and power of the catapult mimicked the kick of a wild ass. 

Trebuchet: This catapult was designed for maximum force, for the stones it hurled were meant to demolish city walls. Believed to be created by the Chinese in 300 AD, the Trebuchet arrived in Europe around 500 AD. The catapult consisted of a long arm (up to 60 ft) balanced on a fulcrum far from the center. A shorter arm was attached to a counter balance; a heavy lead weight. A sling is attached to the end of a long arm and a rope is attached to the long arm and pulled down until the counter balance was high in the air. The potential energy is stored in the counterbalance and when the rope is released, the counterbalance plunges straight down. The potential energy is then converted into kinetic energy and when the rope is brought to a stop, the projectile continues to move. The Trebuchet was the most feared and hated siege weapon and those who manned the catapult were called "gynours". The most powerful and famous Trebuchet was the WarWolf designed and constructed by Master James of St. George. 

MY CATAPULT:

                   . 

While building my catapult, I ran into two problems

1) The trigger mechanism prevented a fluid motion for the lever.

 it continually got in the way, and so I had decided to move it. 

 Thus, allowing the lever to snap forward in a more efficient manner.                                                        

2) The snapping of the lever was too strong for the plastic spoon,                                                           and after several attempts, the plastic spoon began to crack. I was                                                         able to solve this problem by adding duct tape, which could cushion the hitting force and act as a protective layer around the spoon.

                                          

PROCESS

STEP 1: Remove trigger arm

STEP 2: Remove trigger mechanism
(only leaving spring and lever)

STEP 3: Attach spoon to lever with

several rounds of duct tape

(convex side up)

Daniel Wang's Honors Physics Blog

EXPECTATIONS OF HONORS PHYSICS

       By taking the Honors Physics course during my 9th grade year, I hope to get a sense of appreciation for the true nature of Science. I hope to defy my basic understandings of the universe and learn things for which I would have never thought of as true. I hope to learn about the many theories that explain how and why things move the way they do on Earth, all while delving into the depths of the outer space and exploring what lies not only beyond our Earth, but past our galaxy as well. By examining the nature of objects on Earth, I hope to learn things that will completely blow my mind and change my perspective on everyday life. I also hope to get a sense of respect to all scientists and the contributions they made to the field .
       In addition, by taking this course I hope to improve on my basic problem solving skills and be able to adapt to different situations. I hope to learn how to take what I know and apply it to different formulas to be able to find what I don't know. Not only will this help my physics and math skills, problem solving could also transfer to everyday life and help me become a more knowledgable person. Lastly, I hope to fully master all of which this course has to offer, thus enabling myself for AP Chemistry, AP Biology, and AP Psychology for the years to come. All in all, I hope to have a fun year in Honors Physics and become a better scientist