Right-hand comes into play.

A majority of people are right handed, and therefore do almost about everything with their right hand. Here is yet another thing you can add onto the list of helpful things your handy dandy right hand does for you; figuring out the magnetic field based on the direction of current flow. These rules were discovered by a scientist called Oersted.

1. Right-hand rule #1 for conventional current flow: Take the conductor with the thumb of the right hand pointing in the direction of conventional current flow. Your curved fingers show the direction of the magnetic field around the conductor. As you are aware, current flows from positive to negative.

2. Right-hand rule #2 for conventional current flow: Hold the coiled conductor with the right hand so that the curved fingers point in the positive current flow. The thumb points in the direction of the magnetic field within the coil. North end of the electromagnet produced by the coil is represented by outside the thumb. This predicts the relationship between the direction of conventional current flow and the magnetic field at the end of the electromagnet. You must also keep in mind that the thumb points to the North, and the fingers point to the direction of the current.


Here is also a link that you can watch a video on the right-hand rules to clarify any questions you have.
http://www.youtube.com/watch?v=qqkUeQ0nsF8&feature=related

-Peggy.

Test Alert!

Yes test alert! Which means we are having a test very soon. Next week Tuesday 28, we are having a test. We have almost completed this chapter and are moving on. As Mr. Chung said, our tests will be about four questions, but beware, these are four difficult and time consuming questions. Preparation is mandatory in order to receive an excellent mark on this test. So study study study! Also today in class we had a work period to complete unfinished work, which was very useful because I was able to complete almost all of my assignment, which is due this Wednesday, don't forget! We are also advised to take ten points from the book from pages 582-589. So here it goes.

• Magnetic field is the distribution of force in an area of the magnet. There are two magnetic characteristics, north and south, which control the force of the magnet. In other words, opposites attract each other. If you have ever tried to stick two magnets together and you can feel a force between them that will not allow them to come together, it is because you are trying to attach north and north or south and south together.
  
• Ferromagnetic metals are magnets that attract certain metals and are not magnets. These metals include iron, nickel, cobalt or a mixture of the three.
  
• The domain theory of magnets states that ferromagnetic elements have an atomic structure that makes them strongly magnetic. Magnetic materials are made up of a lot of smaller magnets.
  
• The textbook definition of domain theory is that all large magnets are made up of many smaller and rotatable magnets, called dipoles, which can interact with other dipoles close by. If dipoles line up, a small magnetic domain will form.
  
• Oersted's principle: Charge that is moving through a conductor produces a circular magnetic field around the conductor.
  

• Scientists have come up with an easier way to predict the direction of the electromagnetic force from the current. This is called the right-hand rule because it involves using your right hand. There are three right-hand rules.
  (Right-hand rule # 1,2 are written in tomorrow's blog because we have a lesson on it in class tomorrow, so check that! However here is right-hand rule #3)
  

1. Right-hand rule #3 for conventional flow, the motor principle: Open the right hand so that your fingers are in the direction of the magnetic field. Your thumb should point in the direction of conventional flow. The palms show the direction of the force produced.
   

• Demagnetization is the process of ferromagnetic materials become demagnetized.
• Reverse magnetization is when polarity is reversed.
  
• It is proven that a magnet has a limit as to how much it can become strong. Once it has reached its limit, it will no longer be stronger that what it already is.
  
• Magnetic induction is when ferromagnetic materials can be magnetized. An example of this would be when the Earth does this to train tracks, steel and girders.

Make sure to study for the test on Tuesday because it is our first real mark. Good luck!

-Peggy.

Facts Facts Facts !

Hi there. Today in class we completed our Ohm's Law experiment and came up with very interesting outcomes. Tonight's assignment is to write down ten interesting and useful fact from pages 553-563. So here they are.

• Current flow in a circuit depends on two things. 1) Potential difference of the power supply. 2) the nature of the pathway through the loads using the potential energy.
• Resistance is that the more difficult the path, the more opposition there is to flow. Resistance is the measure of the flow. Resistance is measure in volts/ampere which has the unit of ohm. Therefore
• There are many factors that affect resistance, for example the thickness of a wire, length, cross-sectional area, the material it is made of and the temperature of the object. Here is a chart from our book (pg 557) that shows the factors that affect resistance.
• Superconductivity is the ability of a material to conduct electricity without it losing heat.
• Kirchhoff's current law states that the total amount of current into a junction point of a circuit equals the total current that flows out of that same junction.
  
• Kirchhoff's voltage law says that the total of all electrical potential decreases in any complete circuit loop is equal to any potential increases in that circuit loop.
  
• His laws are related to the laws of conservation of electric charge and the conservation of energy.
  
• The resistance in series is that as current passes through more resistors, the voltage decreases as it passes each resistor. The sum of the voltage drop gives the overall voltage drop in the circuit.
  
• The total current must split and distribute itself amongst all of the circuit paths, in a parallel circuit.
  

• Three way light bulbs can have three different light intensities. The filaments are connected in parallel and can be turned on separately or at the same time, producing different intensities.

This is all the notes for tonight.
Goodbye!

-Peggy.

Voltmeter or Ammeter?

Hello there. Today in class we performed a mini experiment and tried to turn on a light bulb. This lab was short but very fun and educational. We were put into groups and were given a small light bulb, a voltmeter, ammeter, four wires and two batteries. We also learned how to read voltmeters and ammeters. The bottom part of our sheet was a chart which we had to fill out. So here it is.

Make sure you all memorize these for the upcoming tests!
Bye.

-Peggy.

Can you make it work?

Physics is all about using your brain, and coming up with answers. Sometimes the best way of learning is by peforming an experiment and seeing the results for yourself. On Friday, we did a mini experiment with a small energy ball and answered a set of questions.

1. Q: Can you make the energy ball work? What do you think makes the ball flash and hum?
A: The energy ball has two metal parts, and when you place both of your fingers on the metals, it will light up and hum.

2. Q: Why do you have to touch both metal contacts to make the ball work?
A: In order to make the ball work, when you place one finger on each metal contact, it creates a closed circuit which is what causes the ball to light up and hum.

3. Q: Will the ball light up if you connect the contacts with any metal?
A: Through experiment, we have concluded that the metal ball will not work with any material, but only with ones that conduct electricity.

4. Q: Which materials will make the energy ball work?
A: Materials like metal, copper and lead will make the energy ball work, because they are all good conductors of electricity.

5. Q: This ball does not work on certain individual- What could cause this to happen?
A: If the individual is wearing gloves or a cloth on their hand it will not work. Also if you use your fingernails, it will also not work.

6. Q: Can you make the energy ball work with all 5-6 individuals in your group? Will it work with the entire class?
A: Making the ball work with 5-6 people or everyone in the class is certainly no problem. As long as everyone is connected to one another, and two people are touching the metal part of the ball.

7. Q: What kind of a circuit can you form with one energy ball?
A: The kind of circuit you can create with one energy ball is series and parallel circuit, depending on how everyone is creating the circuit.

8. Q: Given two balls can you create a circuit whete both balls light up?
A: Yes it is possible to create a circuit where both of the balls light up.

9. Q: What do you think will happen if one person lets go of the other person's hand and why?
A: Depending on the type of circuit that has been created, the ball will or will not stop working. If there is a parallel circuit, depending on where you disconnect the circuit, the ball will still work. If it is a series circuit, no matter where you disconnect the wire, the ball will stop working.

10. Q: Does it matter who lets go?
A: In a seies circuit, it does not matter who lets go, the ball will stop working either way. But in a parallel circuit, if the parallel wires are disconected, the ball will continue to work, but if the circuit is cut off at one of the two ends that are connected to the ball, the ball will not hum or light up.

11. Q: Can you create a circuit where only one ball light?
A: Yes you can create a circuit which has two balls connected to it, but only manage to turn one on. You can do this by creating a parallel circuit, and connected the two balls at two different ends.

12. Q: What is the maximum number of people required to complete this?
A: The maximum number of people you need to make one out of two balls work is three people.

What is the difference between a parallel and series circuit?
In a series circuit, the loads are connected in a row after each other in one path. However a parallel circuit the loads are beside each other, each on a separate wire, both connected to the main source. These two circuits perform in different ways in which potential difference and current each perform separate tasks.
That is all for today.
Make sure you guys download the assignment Mr.Chung has left for us, because it is due in two weeks!
Bye.

-Peggy.

Who can build it higher?

Yesterday in class we had a challenge. We were divided into groups of three, and were given the task of building the tallest and most stable structure out of five sheets of newspaper and a long piece of tape. We had 20 minutes to complete the task. The final product had to be able to stand on its own and not tip over and be the tallest in the class. My group members and I had a little difficulty at first trying to decide how we can make our structure the tallest yet at the same time stable enough to stand on its own. After a few tries, we finally settled on one design.

What we did first was build the structure first, and then build a base for it. We rolled up three pieces of newspaper diagonally and attached them to each other. Once we were satisfied with the height, we worked on building a base that was strong enough to support the body. As we had previously learned in physics class, a triangular base is the strongest and can support the most weight. We then made three equal sized rolls to attach to the bottom of the structure, to create a triangular shape. However, in doing this, we faced the challenge of keeping the structure balanced. We also had another sheet of newspaper left over, so we decided to attach the bottom of the tower to the newspaper, with tape. In doing so, the base became more stable and was able to hold up the weight of the rest of the structure.
When building a tall structure, the most important part is the base, because it is the part that will hold up your creation. If it is not strong, your structure will collapse. Also the weight has to be proportionate. You can not have one side of the structure heavier than the other side, unless you have come up with a way to keep it stable.
There are also physics in building structures. You must think of proportion, weight, base, and height before you can build a structure strong enough to stand on its own.

All in all, I think that our group did a great job, considering the small amount of time we had, and the limited supplies. We did not win, however, we came very close to winning.
There was one group who was able to build the tallest tower, and they won because they learned that it is not always about rolling paper and attaching it together to make it tall, but sometimes you can attach one long light piece of newspaper to the top, which can claim the prize!
So congratulations to the winning group!
Here is the picture of our groups tower.


Here is a picture of the winning group. (Picture taken with their permission)

As you can probably see, the winning group has a long piece of newspaper attached to the top of their structure. It is light weight and didn't hold down the structure or cause it to collapse. Which is what caused this group to win. They also had a strong base, which is the most important, in order to keep their structure steady.
Thanks,

-Peggy.

The Birth of Physics!

After a long and hot summer, we are all finally back to school and ready to learn learn learn! Each year, the work gets more challenging and requires more of your time to understand the concept being taught. This year in Physics class, we have started out by creating a personal blog in which we keep track of the material we learn in class. Blogs are great ways to review what you have already learned, especially when it comes close to a test or exam. I am very excited to start out the year like this, and am hoping for a wonderful experience in Physics class with Mr. Chung ! Hopefully we all learn fascinating things about physics, because I am so excited to get started.

This is indeed my first blog entry since school has started, which will be followed by many more entries filled with knowledge and useful information about the things I learn daily.
Our first task is to read pages 544-552 and come up with 10 points you think is important.

• Electric current is when charge is carried through a conductor.
  
• Conventional current is when current flow moves from the positive terminal to the negative terminal of a power source.
  
• I is measured in amperes (A), Q is the charge measured in coulombs (C), and t is the time in seconds.
• Current, C/s, is the rate of charge flow and is given the symbol I. It is the complete amount of charge moving past a point in a conductor divided by the time it takes.
• Ammeters are devices used to measure current, which needs to be wired in order for the current to flow through it. It needs to be an excellent conductor so that so energy is lost when something else is added to the circuit.
  
• Direct current (DC) is the flow of current in a single direction from the power supply through the conductor to the load, which could be a light bulb, and back to the power supply.
  
• Alternating current (AC) is when the electrons periodically reverse the direction of their flow.
  

Here is a picture of a simple circuit. The path of a current is called a circuit and it is required for any electrical device to work properly.
TIP: In order to be successful in drawing circuits, you need to learn the symbols provided for different items. For more help, look at page 547 in your textbook.

• Electrical potential difference (v) is the electrical potential energy for each coulomb of charge in a circuit.
  
• Voltage is the potential difference of a charge. One volt is the electric potential difference between two points if one joule (J) is needed to move one coulomb (C) of charge of two points.
  
• E=VIt is the energy transferred by charge flow, where E is the energy measured in joules, V is the potential difference in volts, I is the current which is measured in amperes, and t is the time in seconds.
  
• A Voltmeter can be used to measure the potential difference between two points. It must be connected in parallel with one of the loads in the circuit so that the potential before and after can be determined.
  

Here is the list of symbols you need to know for drawing circuits.
Enjoy !

-Peggy.