The Final Chapter... ELECTRIC CIRCUITS

To begin my posting on electricity I will first explain a little about what a DC Circuit is.

First off, a DC circuit (DC for direct current), is an electrical circuit which is made of constant voltage, current sources and resistors. Now I know you may be wondering well what is an electrical circuit?  To put it simply, it is network which exsists in a closed loop. From a source, the current will carry energy on this closed path. It is an absolute requirement that the electrical circuit be a CLOSED LOOP!

Above is a an example of a series circuit

In a series circuit there is only one path for the current to follow as clearly shown above.

Because the current has only one path, the current is the same at all points along the wire.

Regarding voltage in a series circuit...  the equation is :

This equation proves that the the sum of the voltage drops is equal to the voltage drop across the entire circuit.

Above is a parallel circuit which is a circuit where the current has two or more paths to follow.

Because the current has two or more paths to follow, the total current is the sum of the currents through each resistor.

The equation for current is:

You must pay particular attention to the value of R you are using. If you are told to find a particular current in a certain resistor you must used the R value which corresponds to the resistor.

In contrast to the series circuit, the voltage drop is equal to the voltage of the source. This is proved by the equation:

 

Above is a complex circuit, containing both a parallel and series circuit.
It is a network, still closed loop, which has a return path for the current. This circuit connects two or more components.

The current of such a circuit is calcuated in a different way. First you must find the current R(p) which is found again by the equation:

After this you have to calculate in the other resistance (of the series) to calculate the entire R(e).
Now in order to find the current in the circuit you have to plug the R(e) into the equation:

Now you are able to find and solve for the current (I).

Regarding the Voltage...

You can find the voltage across an individual resistor by the equation: V=RI. Something to be careful of is that you are using the correct values when substituting in the numbers. It can many times we tricky if you aren't supposed to used R(e), but instead R(1) or R(2). Also.. this equation is used

It is used when you find the voltage drop in a parallel portion of a circuit. Instead of using the other

When you find the voltage drop across a resistor in a series.

Optics Reflection.

What I've Learned:

Of course there are countless equations, problems, diagrams, etc that I've had to learn. So I won't bore you to death by listing all of them, but instead get to the more important things.

To start out with I learned perhaps one of the most important laws of this section, the law of reflection. In this law it is stated that the angel of incidence is equal to the angel of reflaction. (both of these angles are measured with respet to the normal "N").

Now there are three important mirrors: flat mirrors, concave mirros, and convex mirror. In a flat mirror the light rays are reflected in the SAME order as they approach it. In concave mirros, there is a spherical surface that is the reflects the light rays. In convex, there is an outside portion of the mirror that is the reflecting surface.

Another important thing I learned about was refraction, or the bending of a ray of light as it passes from one medium to another. The equation: n= c/v with the c= 3 X 10^8 m/s is crucial to solving the problems. Moving onto lenses now... they are somewhat similar but at the same time somewhat opposite from mirrors. A converging (convex) lens is thick in the center and thin at the edges. A diverging (concave) lens is thin in the center and thick at the edges. An important thing to remember in this section is that  a real image is always form on the side of the lens OPPOSITE to the object and the virtual image is on the same side of the lens as the object. Lastly, is the total internal reflection. This states that for incident angels greater than the critical angel, there is NO refracted ray at all, and all of the light is reflected.

What I've Found Difficult:

Compared to other units, I've found this one in particular to be one of the easier ones. But that does not mean there were not tricky pieces of information that I had trouble with, because there certainly were! The most difficult part of the section was the sign convention and the difference between mirrors and lens. In lens the converging lens were convex which meant that the radius of curvature and focal length were both positive. In contrast, concave mirrors are converging and the convex mirrors are diverging.

Problem Solving Skills:
In the section, I used my reason skills the most. When constructing diagrams, I had to use logic to discover (first of all if i was doing it correctly) if the image was real, virtual, upright, inverted, enlarged, or smaller, which was a crucial part of solving the problem. I also learned to slow down and read the question carefully. For example: If the problem said that the mirror was diverging I had to remember to change the focal length to negative even if it was given in a positive quantity. Slowing down and paying attention and having the endurance to finish the problem lead to overall great success in this unit!

Why is the sun ORANGE?: photography project.

When someone thinks of sunsets... it reminds them of beautiful colors and romantic evenings. Who would have ever thought that this captivating occurance had anything to do with physics, but it does! In my picture I emphasize the question... "Why is the sun orange at sunset?" As a student I can only answer it one way... with physics.


In the Earth's atmosphere, there are many particles that have similar sizes to the wavelength of visible light. These wavelengths cause the sun's white light to separate and spilt into distinct units. The two main elements of Earth's atomsphere, Nitrogen and Oxygen, cause both the violet and blue lights to scatter because the small size of their wavelength. When sunsets(or sunrises) occur, the light has to travel much more distance from the Sun to the observer than any other time of the day. This results in the longer wavelengths (red and orange colors) to be more easily seen compared to the shorter wavelengths of blue or violet color that have been highly scattered.

One of many Quotes from Albert Einstein

When assigned this project I knew that picking a single quote from Albert Einstein would be a challenge... this was simply because he has such great knowledge and insight that I knew it would be hard to narrow down one I wanted to reflect on. Scrolling through I found this one that really popped out at me in particular.

"If I were not a physicist, I would probably be a musician. I often think in music.
I live my daydreams in music. I see my life in terms of music. ... I get most joy in life out of music."

Quote Analysis:

Within the quote Albert Einstein is showing his passion for music and how he often goes through life relating his days to that love. Now "thinking in terms of music" might be thought of as impossible but what I believe he is trying to say is how closely he connects his life to the subject. It is not something that he does for 30 minutes a day and just forgets about... but he lives through his enduring passion of music everyday and all day because in life he gets the most joy out of music. A very powerful statement resembling Einstein's deep connection, devotion, and respect for music.

A personal connection...

You know what I absolutely love about this quote is how closely it describes me. If I was not a student, sitting in class or finishing homework up late at night, I would love to be a musician. I find something about great composers, classical music, rock and roll or even country music, absolutely fascinating. I could sit at my piano for hours just playing a simple melody over and over again and not get tired. I have to agree with Einstein, I do get the most joy in life out of music. It is a type of stress relief for me and a huge part of my life. Being brought up with a lot of respect and interest in the subject brings me closer to music and will continue to in the years to come. I think it is very important for people to find something in life that they are passionate about. To me, that point is clearly emphasized in this quote. Einstein is passionate about music, and when using that passion for the enjoyment of others and yourself reminds us what happiness in life is really about, making the world a better place by doing something you love. What a simple yet powerful quote to think about... Perhaps next time I think about turning the tv on, going to the mall, or watching a movie... I will think again and rediscover my passion and joy that I find in music every time I play a few notes...

Group 6: Ski Jumping

For Group 6's project we used a glogster and a pixton to explain our topic of Ski Jumping in the winter Olympics. Enjoy!!


Below is a Pixton. It is a digital tool used to help to create online comic strips. Our group used it to explain how physics relates to Ski Jumping as well as the winners for the 2010 winter Olympics.



Below is a glogster, which is a digital took which helps to create an online collage, being used to explain and introduce ski jumping as a sport (including rules, equipment, and even two video)

Ski Jumping Glogster

Also below is another glogster in order to better view the FBDs and Energy Conservation Diagrams as well as a small description explaining the page.

Ski Jumping FBDs and Energy Conservation Diagrams


Attributions:

1. (ski jumping images) Flickrstrom author: johnny9s
2. (ski jumping videos) Youtube
3. (information), www.wikipedia.org (article: Ski Jumping and the 2010 Winter Olympics), http://www.reachoutmichigan.org/funexperiments/agesubject/lessons/newton/skijumping07.html (article on ski jumping), http://ffden-2.phys.uaf.edu/211_fall2004.web.dir/Brendan_Karchere/Body%20Pages%20(2-5)/Page%203.html (article on the physics behind ski jumping), and http://www.vancouver2010.com/olympic-ski-jumping/additional-information/about-the-sport_146098ob.html (article on 'about the sport')

ENERGY!

WHAT I'VE LEARNED...
I have come across and learned many different and new things in the unit of conservation of energy. To start with energy is a conserved substance-like quantity with the capability to produce change. It is universal, does not come in different "kinds" or exist in different forms, and energy itself is unchanged as it is moved around and is stored in different ways. There are many different ways it is stored such as elastic Eel, kinetic Ek, gravitational potenial Eg, and chemical potential Echem; it can also be stored in the random motion of molecules (Ethermal) or the wave motion of molecules (Esonic).

There are many different ways in which energy can be transferred in or out of a physical system in three ways.
1. working: energy is transferred by forces that causes displacements
2. heating: temperature is a "measure of the average kinetic energy of the molecules of a substance"
3. electromagnetic radiation: can transfer energy such as light, microwaves, ultraviolet light and infrared light

A way to express this energy storage and transfer can be done in an energy conservation bar graph diagram. In it you identify the system, initial energy, final energies, and the energy transfers.

Work: is the measrure of the amount of change that a force produces when it acts on a body; Work is equal to the product of the force and the distance through which the force acts. It is also scalar quantity, meaning there is no direction associated with it. The equation for finding work (w): W=Fx. Where F and x are NOT parallel but F is at the angle with respect to x the equation is W=Fxcos(theta). The units of work are in joules (J). 1 J = 1 Nm (Newton meter). Power is the rate at which work is done by a force. P= W/t=Fx/t=Fv with the unit of watts (W). Kinetic energy is the energy that a body has as a result of its motion. The equation is KE=1/2mv^2 with the units of Joules (J). The gravitational potential energy of a body of mass M at a height H above a given reference level is PE=mgh with the units of Joules (J). The work-energy theorem is the net work done on a body (by the net force) equals the change in the energy of that body. W=ΔKE=ΔPE. Elastic potential energy has to do with elastic materials such as springs etc. PEe=1/2kx^2 where k is the spring constant or force constant (measure the stiffness of a spring in Nm) and x is the displacement (in meters). The units of elastic potential energy are measured in Joules (J). Mechanical energy is the sum f kinetic energy and all forms of potential energy. ME=KE+PE.

WHAT I'VE FOUND DIFFICULT:
Although the unit has not been the most challenging or difficult one I have to to learn about, I still found many difficulties with what I have studied. When constructing energy conservation bar graph diagrams I learned I had to be very careful of what I decided my system was. If including the surface... I had to remember to include the friction in the final chart. If I did not include certain items in my system I had to be sure to remember to put that work into the system or take it out. EXAMPLE: A person pushes a box from a 0m position up a ramp to a stop. In this situation I would need to draw 5 blocks of work from outside the system to go into the system. I found this difficult because a minor error could create problems in the exercise I was working on.

MY PROBLEM SOLVING SKILLS:
AS I continue in my physics career my problem solving skills just seem to get better and better! The postings and reflections are also very helpful for me to determine and get an idea of this progress by writing about them. By putting the amount of effort into my problem solving skills, I can see my growth and growing strengths in the area.
STRENGTHS:
I am now able to look at a problem and careful analyze it with detail. I can distinguish the needed and not needed information that will help me solve my problem. I can effectively use my time to solve the problem by remaining focused on the problem at hand. For example, a couple of months ago I could not concentrate in an anything but silent room. I have learned that, that is not always possible and forced myself to focus in all types of enviroments to get my work done.
WEAKNESSES:
Physics, maths, and languages, are all types of classes that require a firm foundation of knowledge on which you build all types of other knowledge. A knowledge that you have to constantly use and look back to, remembering all that you learned is important and not something you can just forget. This is the part of physics that is most troubling to me. Knowing that I have to apply concepts I learned in September, not only scares me but stresses me out as well! I just need to remember to take it slow and easy and it never hurts to review. For example, a simple problem in energy conservation that requires knowledge of kinetic energy at first surprised me! I mean, I learned that last unit, why would I need it now? Learning that physics is all connected helps me to conquer this stress so now I can now stress less! It will take a little time to get used to but I am sure that I can overcome the stress of problem solving with skills I have learned throught my ENTIRE physics career.

PART B:
The question for this section should be how can I stop making connections with what we have studied and everyday life, history, situations in the world and any othe subject. The conservation of energy is EVERYWHERE! From driving up hills on your way to school, to walking up the four flights of stairs to your next class, to the kinetic energy of electrons when you watch your favorite tv show, the possibiltes are endless!
Kinetic energy: kinetic energy of an electron in a television picture
Potential energy: the potential energy of driving your car up a hill
Elastic potential energy: the elastic potential energy of jumping on your trampoline in the backyard for fun
Mechanical energy: riding your favorite roller coaster at Six Flags and finding your present speed/energy at a point along the ride

Knowing that all that I had learned was what literally kept me moving during the day was awesome! Energy conservation is not just what we learned about, but instead what actually keeps us living.

Attribution:
Physics Classwork and Notes

Buckle Up! Dangerous Driving Conditions

For my project, I decided to answer the question... "What types of weather make driving dangerous and difficult because of friction or lack thereof." To explain my answer I chose to use Glogster, an online collage website, to illustrate my points. Hope you enjoy!

Pippa's Glogster

Attributions:
http://www.madphotoworld.com/2008/04/10/Deepest-Snow-Road.jpgNotes http://www.mediabistro.com/fishbowlny/original/road.jpg
http://icons-pe.wunderground.com/data/wximagenew/g/gemini/1226.jpg
http://www.physicsclassroom.com/Class/Newtlaws/u2l2c1.gif