Unit Blog Post 04/29

We began this unit with learnig about domains. Domains are a cluster of electrons spinning in the same direction. On a magnet there is a north and a south pole. The North attracts the South but repels the north. How does a paperclip stick to a magnet? A a paper clip has random domains. The magnet has a magnetic field. WHen the magnet is close to the paperclip the domains in the paper clip will align with the magnetic field in the magnet. The paperclip now has a north and south end. The north pole of the paperclip is attracted to the south pole of the magnet thus the paperclip sticks to the magnet. When drawing a picture of the magnet on earch the geographical North has the south pole of the magnet whereas the geographical north has the north pole of the magnet. All moving charges will feel a force in a magnetic field when they are moving perpendicular to the magnetic field. We then made a motor. A motor is made up of a battery, wire, paperclips and magnet. The battery sends a current through the wire, the wire carries current and reacts to magnetic fields the paperclips conduct electricity and the magnet acts as the force. The reason a motor of a fan for example works is because the motor of a fan consists of a magnet and a currenct carrying wire. The magnetic field exerts a force on the wire. this force will cause a torque. the torque will ultimately start the wire moving if the wire is perpendicular to the magnetic field. Once the wire is turning the fan blades will turn. When then learned about electromagnetic induction. Electromagnetic induction's principles apply to why stop lights know you are there, why credit card work, and how a metal detector works at an airport. This is the answer to why a credit card machine works: there is a coil of wire inside the maching (no current). On the credit card are a series of magnets. When the magnets pass through the loop of wire the magnetic field will change. This change will induce a current. Finally the cirrent will act as a signal to tell the computer what the credit card number is. We then learned about a transformer. In order to know exactly what a transformer is you must be aware of this equation: # of turns in primary/primary voltage=# of turns in secondary/secondary voltage. In the primary voltage you establish the AC current as the current goes back and forth you are changing the magnetic field. This will also change the magnetic field of the secondary loop inducing a current. If we increase the # of turns in the secondary, the voltage will increase if we decrease the # of turns in the secondary the voltage and current decrease. In other words AC current is used because the alternation which changes the magnetic field which induces a current. Generators are mechanical energy in and electrical out in a generatir you are moving magnets over wires which changes the magnetic field of the wire which induces a voltage, which causes a current, the current is used to run a lightbulb or blender. There are two right hand rules. On of the rules is that your index finger represents the current your middle finger represents the magnetic field and the thumb represents the direction of moving charged particles. ALso big appliances use step down where as smaller appliances use step up.
 My effort towards class is pretty consistent and I feel that I am a persistent participant. I also go in early when I feel that it is necessary. And my effort is reflected in-group work especially, which is a time that I am fully involved with the activities. I do my homework every night.  By going in early and asking questions in class I feel that I have strong communication. And my creativity was reflected when making the podcast, and how my partners and me would use real life examples and then further discuss them. My goal for the next unit is to make sure I study before each quiz and go in early to be tested on my knowledge of that particular unit. The connections I make with everyday have been pretty obvious in this unit. these connections include why credit card, airport security and traffic lights work (electromagnetic induction) also we learned how motors work and why paper clips stick to magnets.


 

Motor Blog

When i was first introduced to the motor blog we were told that the motor was made up of large coils of wire and a magnet in order for the coils of wire to work it has to have electricity and it is the wire that fuels a force in a magnetic field. We were then given our handout that explained the project. The motor is made up of a battery coil of wire, paperclip and magnet. the battery will make the wire magnatized or supply the current. The coil of wire carries energy and current. the paperclip conducts current from battery to copper wire to complete the current. The magnet is the force that moves the coils to supply the magnetic field. When drawing this motor the battery has a north and south and you must draw the batteries magnetic field. Then the currrent goes up the paperclip through the motor loop and back down. However, in the wire all of the charges are not moving in one direction. We know that  if the a wire with current is placed in a magnetic field than the current is perependicular to the magnetic field and will feel a force. After looping the wire i had to scrape the plastic of the ends of the wire so that the metal will come into contact. ALso the wire will have a torque on it in order for it to spin. We then learned about hte hand rule and that is that the thumb is the direction the wire will be forced, the index finger is the current, and the middle finger is the magnetic field. the stronger the magnet and more coils makes the motor faster. In order to fully understand this unit I will answer the question : Why did the loop o fthe wire turn on top of the battery? What could this be used for? The current carryng wire feels a force in a magnetic field. And the current carrying wire feuls the foce of the magnetic field. Motors could be used to turn the wheel of a car or a blender, or fan.

Resource

http://video.nationalgeographic.com/video/kids/cartoons-tv-movies-kids/i-didnt-know-that-kids/idkt-magnets-kids/

this video does a great job of explaining the basic principles of magnets. It explains that a significant amount of the things on this earth have magnets. It also talked about the north and south ends of magnets and how opposites attract. It then gave an example of electromagnetic induction which is in fact what roller coasters rely on. It explains how in a roller coaster the magnets in the drop car produces its own magnetic field and then electric current is produced through friction. I highly recommend this video as a study tool because it explains magnets in an easy way to understand and it pacts the video with multiple real life examples. 

Unit Blog

Physics Blog

1. This unit began with learning about charges. There are two types of charges, negative(or electrons) and positive(protons). Opposite forces attract whereas negative forces repel each other. There are three ways to charge something. YOu can charge something through direct contact, friction and induction. induction is way to charge something without direct contact. In this section we answered an important question: Why does your hair stand up after putting on a sweater. The answer is that the sweater steals electrons through friction. So the sweater becomes negative and the hair becomes positive. Because the hair is positive and wants to repel each other it will stick up and repel the other pos charge hairs. We then went on to learn about Polarization. There are a few important vocabulary words to be familiar with. Conductors-let charges move through the object and insulators-stop charges from moving. polar- charges separate from each other. There is an important law in this section, Coulomb's Law. This law states that the force between any charges in inversely proportional to the distance. Therefore the larger the distance the less force.     F=K q1 * q2 /d^2. This is the complete answer to why plastic wrap sticks to the bowel. 1. Plastic Wraps is charged by friction and when brought near the bowel the bowel polarizes. 2. The positive charges in the bowel move close to the negative plastic wrap and the negative charges move away from the plastic wrap.  3. The distance between the opposite/ attractive charges is smaller than the distance between the like/repelling forces. 4.  F=K q1 * q2 5. Since there is a greater distance between the repulsive force the force between them will be less than the attractive forces. 6. Thus, the plastic wrap sticks to the bowel. The next section was electric fields and shielding. An electric field-area around a charge that can influence(push/pull) another charge. The arrow in the fields represents which way the positive charges will pull. also the closer the lines are together--the stronger the electric field. sensitive electronic devices need to be in a metal container so the charges are not pushed or pulled anyway. Electric shielding- inside metal container changes with the distribute evenly, no force. We then learned about electrical potential energy. Electric potential- pulling opposite charges together potential to repel away or build up potential energy between attractive charges. electrical potential is the electric potential energy/charge. We then went on to learn about voltage and current. Current is the flow of electric charge. voltage is electrical pressure or a measure of electrical difference. resistance is the resistance of a material to the flow of electrical charge. difference in voltage is the same as the difference in electrical potential. if there is more resistance there is less current. Therefore a thing long wire has less current and a high resistance whereas a wide short wire has more current and low resistance. you must have voltage (electric potential) difference to cause a current. voltage=potential energy/ charge. We then learned that a power company does not give you electrons but rather we pay for energy. There are two types of current. AC-or alternate current is seen in an outlet in a wall. and DC-or direct current which is seen in a battery. The reason a light is so quick to react is because of the electric/energy signal because electrons move slowly. We then learned about series and parallel circuits. in a series circuit the current remains the same when you add another lightbulb. whereas in the parallel circuit the current is greater. In a series circuit the resistance is greater when adding a lightbulb in series and the same when adding a lightbulb in parallel. If you unplug one appliance that is wired in parallel the others will still remain on whereas if you unplug one in series every other one with turn off. 

 My effort towards class is pretty consistent and I feel that I am a persistent participant. I also go in early when I feel that it is necessary. And my effort is reflected in-group work especially, which is a time that I am fully involved with the activities. I do my homework every night.  By going in early and asking questions in class I feel that I have strong communication. And my creativity was reflected when making the podcast, and how my partners and me would use real life examples and then further discuss them. My goal for the next unit is to make sure I study before each quiz and go in early to be tested on my knowledge of that particular unit. The connections I make with everyday have been pretty obvious in this unit. This so is because we have been discussing how lightbulbs work and how you get power in your house. Also we learned the answers to important questions such as why your hair sticks up when taking off a sweater and why people use dryer sheets. 

 

Picture Blog

 
This is a picture of a power strip. A power strip is a nice way to think of a parallel circuit. A parallel circuit is a closed circuit in which the current divides into two or more paths before recombining to complete the circuit. Therefore if something is wired in a parallel circuit and i unplugged my computer charger, my fan, light, and other computer charger would remain on. The other type of circuit is a series circuit. A series circuit is an electric circuit connected so that the current passes through each circuit element in turn without branching. In other words if you unplugged one item they would all turn off.