January 25, 08 -Last scribe for physics!

I almost forgot to scribe! Anyways, in class, nothing much happened. It was just a basic free period class to work on review for the upcoming physics exam.

Physics exam:
Monday, January 28 /08
Gym, 1-4
For Grade 12 Physics.

Today...

Today we didn't do much at all. We watched a Movie on Radio activity. And for the remainder of the class, Ms. K handed out our tests and we went over the answers! ..

Physics exam is coming soon, so study lots!

Today in Physics....

We went over the questions in the green textbook, and then we went over the review for the test tomorrow.

Reminder that the exam is on the 28th in the afternoon. STUDY STUDY STUDY!

The scribe for tomorrow is...sandy!

The, super late friday scribe

Big misunderstanding, and I just remembered to do that scribe, now. I did tell Steven... but I guess not. Anyways:

We went over some work sheets, the Chapter 25 study guide, and we were assigned the end of the chapter questions.

Exam is in the Afternoon, Jan 28. 1pm.

Test for this unit is on Wednesday, Jan 16.

Next scribe... Steven.

Electricity and Electromagnetism

Make an on-line slideshow at www.OneTrueMedia.com

Wednesday, January 8, 2008

OK time to do this.... today in class we had some notes on Electromagnetic Induction and Magnetic Fields. After that we worked on an Electromagnetic Induction worksheet, and also got an Induced EMF sheet that has other formulas and such. We will be going over some of the exercises tomorrow in class so it is best to have those ready I suppose. I am now going to get my much needed rest, haha.
Florjeval can scribe for tomorrow.

Scribe #4

Well, time to blog once again. Well today was not very interesting, Ms. K was not in class because it is Ukrainian Christmas which she was celebrating. Well the sub we had in class went over the compound worksheet Ms. K gave out to us just before the Christmas break. Then the sub handed out two worksheets, one was a vocabulary work sheet which had to be done by reading pages 515-529 in the green book prior to completion. The second was a multiple choice worksheet on electricity definitions. Well that was all that was done in class today, make sure to have both of those worksheets completed for tomorrow.

The next scribe is going to be Renan.

FIRST OF ALL...

MERRY CHRISTMAS & HAPPY NEW YEAR

HAPPY HOLIDAYS

Hey guys! (and Mrs. Kozoriz!) Did you have a great winter break? I finally got this post up. I have been procrastinating on everything. I had so much time that I didn't know when to actually do this post. I didn't realize that we go back to school on Monday until today. Pretty sad... I hope everyone's all pumped up for the new year even though it means GOING BACK TO SCHOOL. No more sleeping in - BOOO!! I hope you guys are happy with all the presents you got from your loved ones. However, we should turn our switches back on to let the current flow in our circuits because guess what? MORE CIRCUITS when we get back! HAHAHA! Anyway...

DECEMBER 21, 2007 AGENDA:

We went over the `Simple Circuits` worksheet. I can't remember anything else that happened except for a few people decorating Mrs. Kozoriz's white board according to the aforementioned holiday of the year. Everyone was basically excited for the tantalizing two-week holiday. We were all excited to exit the doors, go home, hang out with friends, and finally be able to sleep in everyday! Of course, there are PRESENTS waiting to be opened.

Here are the answers for those who didn't take them down last year.


1.a)



b) Resistance_total = 10Ω + 10Ω + 10Ω = 30Ω (The Greek letter, Ω, represents OHMS, which is the unit for resistance.)

c)

(The unit for current, I, is A or amperes.)

d) Potential Drop = 0.4A x 10Ω = 4V (The unit for potential drop is volts, or V.)

e) Current = 12V / 30Ω = 0.4A

(Note that the total current circulating a SERIES CIRCUIT is the same as the current that goes through each of the resistor.)

f) Power = 4V x 0.4A = 1.6W (Watt is the unit for power.)

2.a) b)

c) Current_total = 12V / 3.3Ω = 3.6A

d) Potential Drop = 12 V (In a parallel circuit, each resistor has the same potential drop.)
e) Current in each resistor = 3.6A / 3 = 1.2A
f) Power = 1.2A x 12V = 14.4W



3) Series circuit = 2.4 watts; Parallel circuit = 11 watts


4.a) 1440Ω
b) 0.16A


REVIEW:

• Electric Potential - is the electric potential energy per unit of charge
• E = qV
• Electric Potential Difference (voltage) - ∆V

*** It is necessary to determine the total or equivalent resistance of the circuit before other elctrical quantities can be calculated. It is also important to identify the resistors that are in series with each other and those that are parallel with each other.

*** Add the resistors to reduce the number of resistors in the circuit. Begin by looking at the resistors furthest from the source (battery).

• Kirchoff's Current Law - the sum of the currents entering a junction must equal the sum of the currents leaving the same junction
• Kirchoff's Voltage Law - the sum of the potential drops around a circuit must euqal the sum of potential rises around the circuit
• Factors that affect resistance :

1. Length - the longer the conductor, the greater the resistance
2. Cross Sectional Area- the larger the cross sectional area, the less resistant it is to charge flow
3. Temperature - the greater the molecular motion, at higher temperatures, the greater the resistance (not for all substances)
4. Type of Material - some materials are better conductors than others.

• RESISTIVITY - general measure of the resistance of a substance, has units Ωm

- where R is the resistance in ohms, L is the length in meters, A is the cross-sectional area, in meters² and ρ is the resistivity in Ωm²/ m

• Five steps to follow to successfully analyze a compound circuit:

1. Each set of parallel conductors must be replaced by a single equivalent resistance
2. Each series resistance must be combined to find the total.
3. Total current in the circuit can be found using the equation: I = V / R
4. The voltage across each series group is found using: V = IR; to check, the total voltage must equal the sum of the individual voltage
5. The current in each branch of the parallel conductors can be found using: I = V / R; to check, the total current must equal the sum of individual currents

Oh and I remember now. We got more worksheets for this unit. Make sure you do them! Be careful because they are tricky. You can easily get confused and mix up the rules for series and parallel circuits. See you guys on January 7, 2008. Lastly, the next scribe is DINO!

HAPPY NEW YEAR TO ALL!

HAVE A GREAT 2008!!!

Physics 40S 3rd Period

sorry for the late scribe,!well, yesterday in class we went thru chapter 23 study guide about Simple circuits.then we went also, over the other sheet that Ms. K gave to us on electric current. We answered the sheet. Ms.K showed us a demo about the 5 bulb and a 2 which is the 2 bulb is brighter (parallel) than the 5 (series)and that's it for now....have a good and happy holiday guys..!!

Next Scribe for Friday: Vincent!!!

Scribe Post

Well today we got back our tests after much anticipation of our marks. We went over the Electric Circuits sheet that Ms. K posted the answers to. We went over the 23 chapter guide.

We also were given a lab to do which didn't go all so well because most of us had a hard time understanding exactly what it was asking. I'm guessing that tomorrow we will probably be going over the lab.

Also the test for Electric Circuits has been moved to the second week that we come back from holidays; it will be joined to our next unit as one big test. This happened after lots of complaining of the lack of knowledge in this unit.

That was basically all of today's class, and the tomorrow's scribe will be .........Hall of Fame!

Hope everyone enjoyed the festive colours=)

Electric Circuits

Hello all! I am your scribe for today.

So we had a substitute in today for Ms. K who gave us a few sheets to work on for the class. All of which were about electric circuits. The sub was pretty helpful and not only helped us with using our units and types of circuits but also gave us quite the inspirational speech on being persistent in learning physics.

That's really all that happened today, so I thought I'd include some hyperlinks to some websites that discuss electric circuits that may help anyone who is having trouble with the concepts....

Tomorrow's Scribe will be Nicole!!

http://www.math.ucdavis.edu/~daddel/linear_algebra_appl/Applications/Electrical_Circuits/Electrical_Circuits.html

http://www.hyperstaffs.info/work/physics/child/index.html

1 - December 17 - Scribe

We picked up 3 sheets, The direction of the Electric Current, Chapter 23 Study Guide, Simple Circuits and Henry Cavendish and the First electric Meter. then we did a lab where it was similar to crocodile clips whereby we made circuits where you take light and connect it to an electric supply. Then we answered the questions and then handed it in. We where supposed to correct the test but we had no time.

That basically sums up the class. The next scribe is kim.

Thursday, Dec 13 and Friday, Dec 14

Well so far on Thursday we went over two sheets one of which, The cathode ray problems, has the solutions up on the bottom. After spending half of the class on that we continued onto our review for the test, which is also posted up on the bottom. Of course on Friday we had our electric and magnetic fields test, hope you guys did good on it cause i sure didn't xD.
Next is 1

Scribe Post

This is Oliver speaking, reporting from physics class, from third period. During this class we quickly began by answering questions on the board from a sheet that we were supposed to have done the night before, and that took us a good chunk of the class. We all took turns answering and so the last three questions 14, 15, and 16 are for homework. After this Ms. K showed us this thing where you could tell where the path of a charged particle was in a magnetic field. After that, we basically went into review questions. She handed out a worksheet, chapter 27 and it's to be done for tomorrow, or at least try it. By the looks of it some people had trouble in the beginning already. Good luck everyone ! bye bye. Oliver signing off.

The next scribe is 111111111 !!!!!!! what an awesome name.

magnetic fields and current

Oh dear its Anthony. Sorry about the delayed scribe post. I forgot about it yesterday. Ok anywho if we can recall we learned the right hand rule in grade 11. But for those who forgot about it lets do a refreshment on our old skills. Before we start let me mention a few things.

1) an electron is forced in the opposite direction of a proton.
2) the charge must be moving. A magnetic field will not influence the motion of a charged particle at rest.
3) the velocity of the moving charge must be perpendicular to that of the direction of the magnetic field.
here are easy steps to determine force direction.

*use this for proton

1) open your hand. Now point your fingers in the direction of the magnetic field.
2)rotate your hand so that your thumb points in the direction of the current.
3) look at your palm. the direction your palm is facing is the direction of the force acting upon the charge.

*use for electron

do steps 1-3 above but use your left hand! amazing it works! Because the electron acts opposite to the proton the left hand will work. Founded By Professor Cadonic.

next scribe is oliver

Voltage

Hello everyone MrSiwWy here for today's physics scribe post, in which we actually covered quite a bit. The class began with Ms. K correcting the sheets that we had for homework over the weekend and also by reading pages 4 - 5 on the topics of Work and Kinetic Energy and Electric Potential in the handout booklet she gave to us sometime last week. This booklet's title on the cover is Grade 12 Physics: Gravitational Potential Energy.

For electric potential:

1. "Just as PE (potential energy) transforms to KE (kinetic energy) for a mass lifted against the gravitational field, the electric PE of an electric charge transforms to other forms of energy when it changes location in an electric field. When released, how does the KE acquired by each compare to the decrease in PE?"

The answer: equal (since both require work to move an object while still under the influence of the field whether it's gravitational or electric. Once work has been applied some potential energy has been transformed into kinetic energy in both cases.)

2. "Similarly, a force pushes the charge (called a test charge) closer to a charged sphere. The work done in moving the test charge is the product of the average force and the distance moved. W = FD. This work is equal to the PE of the test charge. If the test charge is released, it will be repelled and fly past the starting point. Its gain in KE at this point is equal to its decrease in PE." (note: terms in bold font are the answers since it was fill in the blanks.)

3. "complete the statements.
-Electric PE/charge has the special name Electric potential.
-Since it is measured in volts it is commonly called voltage."

4. "When a charge of 1 C has an electric PE of 1 J, it has an electric potential of 1 V. When a charge of 2 C has an electric PE of 2 J, its potential is = 1 V." (This is due to the fact that electric potential is the electric potential energy divided by the charge, as stated above in question 3)

5. "If a conductor connected to the terminal of a battery has a potential of 12 volts, then each coulomb of charge on the conductor has a PE of 12."

6. "If a charge of 1 C has a PE of 5000 J, its voltage is 5000 V."

7. "If a charge of 0.001 C has a PE of 5 J, its voltage is 5000 V."

8. "If a charge of 0.0001 C has a PE of 0.5 J, its voltage is 5000 V."

9. "If a rubber balloon is charged to 5000 V, and the quantity of charge on the balloon is 1 millionth coulomb (0.000001 C) then the PE of this charge is only 0.005 J.

10. "Some people get mixed up between force and pressure. Recall that pressure is force per area. Similarly, some people get mixed up between electric PE and voltage. According to this chapter, voltage is electric PE per unit charge."

Next, we moved on to a lab which consumed the majority of today's class time. The lab was essentially the assembly of a figure that embodied the main idea of increasing potential energy within an electric field (raising a charge AKA applying work to raise the charge against the electric field). The procedure and materials required for the lab are approximately similar to the following (since I don't have a green book with me right now):

Materials:

A Ruler
Clay
Steel balls (Any object can substitute for this, such as pennies in this case)
Masking tape

Procedure:

1. Insert a ruler within a molded ball of clay so that the ruler can stand upright without much independent mobility.

2. Take a 2 cm x 8 cm piece of tape and label it "3 V - 3 J/C" and repeat this process for three more equal sized pieces of tape with the labels "6 V - 6 J/C", "9 V - 9 J/C" and "12 V - 12 J/C."

3. Attach these pieces of tape to the ruler approximately at each 3 cm interval indicated on the ruler.

4. Once each piece of tape is attached to the ruler, attach the steel balls (or pennies) to each piece of tape, starting with 4 at the bottom on the 3V piece of tape, then with 3 on the 6V, and so on.

Results

Basically, we were given questions accompanying the lab as usual, and this was our overall analysis for the lab. Now essentially for the lab there was a structure which indicated that the amount of charges decreased as the voltage increased while you move farther up. If you think about the surface the structure is resting on in terms of the base of the electric field, you move the charges upwards and the voltage increases while the charges decrease. This also implicates an energy change, which can be calculated by multiplying the voltage with the amount of charges present at that level. So for this lab, the following data table was completed as the lab progressed:

Here are the corresponding analysis questions for the lab (accompanied by my answers):

"1. How much energy is required to lift each coulomb of charge from the tabletop to the 9-V level?"
The energy required to raise one coulomb of charge from the tabletop to the 9-V level is 9 J of energy. This is due to the fact that there are 2 charges at a voltage of 9 J/C accumulatively giving an energy value of 18 J, but since the question only inquires about the energy of one charge this 18 J is divided by 2 to give 9.

"2. What is the total potential energy stored in the 9-V level?"
(Note that this is basically explaining the calculations made in the table for each energy value)The total potential energy at a given location when you raise the object further up against the electric field can be found by using the electric potential of the object / charge. Since V = PE/q, and both q and V are known, solving for PE gives PE = V*q, PE = (2 C)*(9 J/C) = 18 J.

"3. The total energy of the charges in the 6-V level is not 6 J. Explain this"
The total energy of the charges in this level is not equivalent to 6 J since there are 3 charges present at a voltage of 6 J/C, rather than just one charge at a voltage of 6 J/C. Since there are 3 charges at a voltage of 6 J/C giving an overall energy for the level as 18 J.

"4. How much energy would be given off if the charges in the 9-V level fell to the 6-V level? Explain"
Now since the charges are dropping to a lower voltage at 6 J/C from 9 J/C, an energy equivalent to 3 joules would be emitted from the system since the charges are falling from 9 to 6. * not sure about this one since I can't remember what I actually put and am not in the mentality to reason out the answers momentarily.

Application question

"1. A 9-V battery is very small. A 12-V car battery is very big. Use your model to help explain why two 9-V batteries would not start your car."
Now if you think about it, the more charges that are present then the higher the energy value for that level. Now since these two cases involve voltages that are quite similar, there are obviously much more charges found in the large car battery than in the small 9-V battery, therefore allowing for quite a bit more energy available for use by applying the battery correctly.

Once all the labs were in, Ms. K went over the answers to the other sheet we were given on friday. The answers to the questions are as follows:

1. V = 31 V
2. a] PE = 3.6 x 10^-14 J
2. b] V = 180 V
3. 1.9 x 10 ⁷ m/s
4. 3.2 x 10 ^-9 J
5. a] w = 1.92 x 10 ^-18 J = 12 eV
5. b] E = 1.92 x 10 ^-18 J = 12 eV
5. c] V = 2.0 x 10 ⁶ m/s

Once she finished putting that up, we were let to work on our own on either finishing up the lab or to finish the sheets she put out in the front of class. Jeez, I wish I could've put more so that anyone who doesn't quite understand this unit yet or is yearning for some help with their tribulations concerning problems in this unit. Now as for our homework, the sheets that were up front for pick up are probably going to corrected tomorrowed, and by the way, the test is on friday. Good night everyone and the next scribe for tomorrow's class will be Anthony!

Scribe

Well today we viewed a couple more presentations!

We had a dose of the Mars Mission from Oliver...
and a presentation on telescopes from Sergio.

After we moved on to a couple of the sheets that Kizoriz handed out.

Well that pretty much sums it up.

Have a good weekend.

The next scribe will be...

Mr SiwWy
PS. Afternoon class worked on the Charges, Voltage, Energy lab from the green book.
Make sure you read the notes on potential, potential energy, potential difference.
Note the difference among them (pardon the pun :))

More Presentations...

The title pretty much says it all... Today we had a couple more groups/individuals present their projects. We seem to be learning quite a bit about the Mars Exploration, but we also got to see a bit of Metaphysics from Grey-M and Aichelle.

Remember, all groups should hand in a self evaluation which includes a mark out of 10 for Presentation, a mark out of 40 for the total Project, and explanations as to why they deserve such a mark.

That's all for today... I have to work now, so I'll see you all tomorrow where we will finish the remaining presentations and GREY-M will be scribing about them =D

Scribing time!

Ok, so today was pretty straight forward....it was presentation day! Craig and I started off the class with our presentation of Cosmology using iMovie which was pretty awesome if I do say so myself ;). Next to go was our vice President Vincent! He did his presentation using power point. His was very in depth and he used amazing video's and pictures to get his points across. Last but not least (in any way) was Chris Cadonic's presentation using power point as well. His was on Special and General Relativity and had the basic details of a very well planned lecture. He was able to take a very complicated subject and actually explain it in terms our class understood, even using classmates as examples. His project actually ended up taking the rest of the class but I don't think that anyone really mind, especially Sergio. XD! So I guess that covers what happened in physics today, all the others who still need to present good luck! and the next scribe is.......CRAIG!

Scriiiibe

Hello everyone!
In today's class, we were assigned page 423 questions 7-12 in the green book! YAY! We basically had the whole class to go over that, so I assume we all should have finished! We also viewed Kim's lovely powerpoint presentation on Mars today because she will not be in class tomorrow. Our presentations will take place tomorrow, so hopefully you guys all finished! We also got two sheets titled Electrical Forces and Coulomb's Law. Since we have our presentations taking place tomorrow we should be finished these sheets by Thursday! The scribe for tomorrow will be *KASIA*! okay have fun and have a good night everyone! =)