Newton's blog

Katie Vaughan
4/25/08
Newton Paragraphs
1. Aristotle believed in the constant of acceleration due to gravity. Aristotle noted that even objects with very different weights would fall at the same rate of gravity. Galileo tested this by rolling balls of different weights down the same sloped decline. This would show the equal acceleration, but at a good speed to observe because it was not free falling. We have studied this with the formula of F=mg. G=9.81 m/s^2 and you can use this to see the force applied or the mass of the object that was free falling. The part of the chapter that pertains to this is stated through, “If you drop two bodies that don’t have much air resistance, such as two different lead weights, they fall at the same rate.” This law does not pertain to air resistance that is caught by such objects such as a feather.
2. Another topic that pertains to our physics class was Newton’s 1st Law, which states that “a body will accelerate, or change its speed, at a rate t hat is proportional to the force.” In Newton’s Principia Mathematica is also known as Newton’s First Law it states this law. This law is related to our studies because of the formula F=ma. This equation is used throughout the physics year to find either the force, mass, or the acceleration. The a is always 9.81 m/s^2, if it is on earth, but otherwise you have to find the acceleration due to that planet’s gravity.
3. The last topic that relates to our studies of physics is of the equation of F=Gm1m2/r^2. This applies because of what is stated in the article, “that theory states that every body attracts every other body with a force that is proportional to the mass of each body.” This topic is given to find the mass of either one of the objects, the distance between them, or the force that is applied. The G is a constant given on the physics reference table. This topic that Newton’s theory of gravity, and we learned about this on physics class throughout the year.

Chapter 20 #63

Above is a cross section diagram of the Leyden Jar. Pieter van Masschenbroek invented the Leyden Jar in 1975. The Leyden Jar would be used to store electric charge. The original jar was made out of a glass bottle, and it contained water to conduct electricity. A metal wire was passed through the cork which was used to close the jar. There was a conducting metal foil wrapped around the outside of the jar and also covering some of the inside surface. The inner and outer surfaces of the jar store opposite charges that are of equal amounts.

Franklin’s bells were used as an original form of detecting when an electrical storm was going to occur. This was because when the bells were connected to a lightning rod, they would ring when an electrical storm was close by. This idea was started when Franklin, during one of his experiments, realized that when 2 differently charged objects made contact with each other then they both would become the same charge. He also found that some things were attracted to charged objects. Using this idea he used a bell in place of one of the objects.

Blog Post #63

Pieter van Masschenbroek designed the Leyden Jar to store electric charge in 1975. It was originally made by okaying water into a glass bottle. The water acted as the conductor. A metal wire was then passed through the cork that closed the jar. The design later changed to used metal foil. The new jar was then chared by an electrostatic generator. The inner and outer surfaces store opposite charges that were of equal quantities.
The Wimshurst Machine, designed around 1880 by James Wimshurt is used to generate high voltages. Two large contra-rotating disks are mounted in vertical plan along with two metallic brushes as cross bars, and also included a spark gap. The electric charge is created through electrostatic induction. These two insulated disks and metal cross bars rotate in opposite directions which create an imbalance of charges. Sparks jump across the gap since the positive feedback increases until the dielectric breakdown voltage of the air is reached.

ch 20 #63

During one of Franklin’s initial experiments he noticed that a pith ball or cork would be repelled if touched together but at would be attracted to a charged object. He realized this because the two objects were initially charged differently, but once they touched they acquired the same charge. He later realized if he replaced the charged object with a bell he could make an "electric bell." Later he used the bell as a lightning detector that became known as Franklin’s Bells. When the bell was connected to a lightning rod it would ring when an electrical storm was nearby, which could be used as an early form of weather detection.

The Leyden Jar is a device that was invented by Pieter van Masschenbroek in 1975 to store electric charge. The Leyden Jar was made of a glass bottle with water to act as a conductor for electricity. It was made with a metal wire that passed through a cork which closed the jar. The design of the jar later added a metal foil coating part of the inner surface and a conductor foil wrapped around the outside surface. The jar is also now charged by an electrostatic generator connected to the inner electrode, with the outer plate being grounded. Additionally, the inner and outer surfaces store opposite charges that are equal in amount.

4/1/08 Blog Post

Heyy, so today we started off by Mr. Wirth reminding to scribes to always be alert! Well this one obviously was, because I remember that we started off with a review sheet he handed us...

We did about 4 problems on the sheet that reminded us of the properties of this unit.
We calculated the amount of charge passing through resistor (R2) in 60 seconds. We did this by using I=delta q/T
Next we learned how to draw a parallel circuit using the ammeter symbol, battery, and 2 resistors of a certain ohm.
Lastly we calculated the equivalence resistance of the circuit by using the equation 1/Req=1/R + 1/R2...

After reviewing these concepts we jumped right into notes...
VOLTMETER: measures potential difference between two points in a circuit.
**these are connected in PARALLEL
**extremely HIGH internal resistance
**draws extremely SMALL current

AMMETER: measures current through ONE point in a circuit...
**connected in SERIES
**extremely LOW internal resistance
**creates extremely SMALL voltage drop


so that was all the notes did for the day... by the way ellen missed all of this because she was not here. so i hope she takes full advantage of this blogging experience...

ok peaceout

Chapter 20 Question 63

Leyden Jar
It is a devide for storing electrical charge and was invented in 1745 Pieter van Musschenbroek. It was the first capacitor and was used to conduct experients dealing with electricity. the design consists of an electrode connected to a metal foil folding part on the inner surface of a glass jar. The conducting foil is wrapped around the outside of the jar which is charged by an electrostatis generator, which is connected to the inner electrode and the outter plate is grounded. Both the inner and outter surfaces of the jar hold opposite charges. Originally it was a glass bottle partially filled with water with a wire passing through the cork that closed it. Benjamin Frankilin found out the charge was stored in the glass and not the water.
Franklin's Bells
During one of his initial experiments he noticed that a pith ball or cork would be repelled if touched together but initially would be attracted to a charged object. he realized this because the two objects were initially charged differently, but once they touched they acquired the same charge. He later realized if he replaced the charged object with a bell he could make an "electric bell." Later he used the bell as a lightning detector. When the bell was connected to a lightning rod it would ring when an electrical storm was nearby.

March 25, 2007

Today we began a new unit called Electrical Circuits, which originated in about 1350-1400. A circuit is a closed loop or path along which charged particles move, in which an electrical current can exist. a cirsuit is formed by a source of potential differnce, including one or more resistances.

Circuit elements include:
Source elements: device or system that can produce a potential difference
Load elements: device or system to which the source is connected
Control elements: used to control the flow of electrical current
Path elements: used to interconnect other elements

Circuit symbols can be found on page 4 of the reference tables

Terms and Definitions:
Current (I)- flow of electric charge, the time-rate at which charge flows past a given point in a circuit.
Unit: ampere (A)
1 ampere= 1 coulomb/second 1A=1c/s
equation: I= the change in q/time

The Life of Period 1 Physics Class of March 13, 2008

White Board Review

Today started of as any other review day with the white board questions. Make sure you all know how to draw a single positive charge and a single negative charge. Also, know the pair of positive charges of equal magnitude, positive and negative charge of equal magnitude, as well as a positive and negative charge of different magnitudes. Some of these examples look as follows:

Ok now onto the new material:

Work

-Work is done when a force is appplied over a distance, the unit for work is the Joule. If we move a charge in an electric field, and the charge is repelled by the field, then we do work against the field. The potential energy of the charge is increased by the amount of work done

Electric Potential Difference/ "Potential Difference"

-Consider moving a charge "q" between 2 points A and B. the work we do is "W" and we have thus increased teh potential energy of q by "w" joules. So we have "Work Per Unit Charge" AKA a potential difference exists between points A and B.

Potential Difference is the change in electricl potential energy per unit charge as a charge is moved from one point to the other. V=W/q . . . . (don't worry the equation is on the reference tables) Also V= volts of potential difference

Electron- Volt/ "Amount of Work"
-The tiny amount of work from the previous promblem is defined as the "elecgtron-volt"
- Symbol is eV
Formal Definition
-The energy required to move one elementary charge (e) through a potential difference of one volt (v)

-Electron-Volt is also on the reference tables

Electric Potential
-Similar to the concept of gravitatonal potential
- we used mgh to calculate gravitational potential
- this implies a preference point whre h=0, so gravitational potential=0 at that point
- often we might use sea level as h=0 if the object does not move
-For elecric potential we use a distance of infinity from the charge in question
-Elecgtric potential is defined as a work per unit charge
-work required to birng one coulomb of positive charge in from infinity to a point in an electric field
-results in electric potential energy equal to the work done
-it is a scalar quantity
-unit is jouls/coulomb (j/c)




* BAGEL DAY COUNT-DOWN: 7 DAYS *

#63 Blog Post

The Leyden Jar was a device designed by Pieter van Masschenbroek in 1975 to store electric charge. Originally the Leyden Jar was made of a glass bottle filled a little bit with water to act as a conductor. The jar had a metal wire passing through a cork which closed the jar. At this time there was no outer plate. Later the design changed to a metal foil coating part of the inner surface and a conductor foil wrapped around the outside surface. The jar is also now charged by an electrostatic generator connected to the inner electrode, with the outer plate being grounded. Additionally, the inner and outer surfaces store opposite charges that are equal in amount.
The Wimshurst Machine, was designed between 1880 and 1883 by James Wimshurt to generate high voltages. The device consisted of two large contra-rotating discs, that are mounted in a vertical plane, two cross bars with metallic brushes, and a spark gap. This device creates electric charges through the concept of electrostatic induction. This works when the two insulated disks and the metal sectors rotate in opposite directions passing the crossed metal neutralizer bars and brushes, creating an imbalance of charges. The positive feedback increases the accumulated charges until the dielectric breakdown voltage of the air is reached which is what makes the sparks which jumps across the gap of the two disks.

#63 blog post

Static electricity has been involved in experiments since the 1700s. One of the first experiments with static electricity involved the Leyden Jar. The Leyden jar was invented in 1745 by Pieter van Musschenbroek. This was the first capacitor and were used to conduct experiments involving electricity. The original model was a glass bottle partially filled with water with a metal wire passing through the cork that was used to close the bottle. Another invention that was used for early static electricity experiments was the Wimshurst machine. The Wimshurst machine is an electrostatic device for generating high voltages developed between 1880 and 1883 by James Wimshurst. "It has a distinctive appearance with two large contra-rotating discs mounted in a vertical plane, two cross bars with metallic brushes, and a spark gap formed by two metal spheres." The device did not have the previous disadvantage to temporarily and randomly switch its polarity. Overall the static electricity within history has progressed over the years.

3/7/08 class

happy friday!!

we had our usual bagels for breakfast club brought in by me. Then we did a mini lab. We rubbed fur and silk on plastic and glass rods as well as a ruler. The point of this lab was to determine the charge on these various materials and how their charge changed.

After that we just chilled. the end.

Last Wednesday

Today we spent our time exploring the world of electricity. This post was the introductory day to electricity therefore we spent most of our time doing mini experiments.
We first demonstrated static electricity by rubbing a orange balloon on Austins head. (This balloon was later used on probably 15 students therefore i feel this experiment was highly unsanitary.)
We next demonstrated electricity by rubbing bunny fur to create a "magnetic" charge that would pick us crumbs.
By rubbing plastic and silk the plastic rod was able to pick up bits of paper.
The last experiment was showing how water bent because it was attracting to the certain charged rod.
These experiments demonstrated how opposites attract.

This concludes my blog post. This day was more about experiements that have to be seen rather than heard

PLEASE COMMENT ON THIS WONDERFUL POST!

Physics Explained

By Alex Eberts
Many people have a lot of unanswered questions regarding some of the things that we as humans see on a daily basis. Why do rainbows occur? How are mirages visible? Why is the sky blue? How come there are so many colors in a sunset? All of these questions can be answered using physics. Physics can explain many of the natural phenomenon’s we see everyday.


Glass can create different effects using visible light and the spectrum of colors. The effect glass creates when light is refracted is called dispersion. Dispersion occurs when the different colors, like blue and red, refract or bend in the glass in different ways. One specific device that has this effect is a prism; it breaks up the white light into all of the different colors. Raindrops act as prisms because if the sun is shining while it is raining then the light from the sun will refract or be dispersed off the raindrop. The white light hits the raindrop and when it is dispersed it is separated into different colors. This creates the effect of the rainbow and this is how we see rainbows. The diagram below demonstrates a raindrop acting as a prism with the white light from the sun being dispersed and refracted off it.











The raindrop acts like mirror also because it some of the dispersed light back at the sun. The different colors in the white light enter the raindrop at different angles therefore creating the different colors. Each raindrop only helps to contribute to one beam of light that is seen in the rainbow. Raindrops that are found located higher in the sky are red, orange or yellow light and raindrops that are found located lower in the sky are green, blue and violet. The antisolar line helps us to determine the color we will see. If a raindrop is located at 42° of the antisolar line then we will see red light. This helps to create the rainbow as a whole and make it so large. If the raindrop is located at 40° at the antisolar line then we will see blue light etc. The diagram below helps to explain how we see things due to the antisolar line. (Physics of Rainbows)











Why is the sky blue? Light in the sky is considered to be scattered light. This means that it is made up of many particles that when light is refracted or dispersed off of them it creates the blue sky that we see everyday. However, the sky is not only made up of blue light, it is made up of all the colors of the spectrum our eyes just mainly see blue. The image of clouds in the sky is created a fairly similar way. The reason why our eyes see white clouds is because it is light bouncing of water particles in the air. Therefore the clouds may look white and opaque, but they are really transparent.(Physics of the Blue Sky)

Sunsets and sunrises have the effect of being very colorful because of light scattering off of molecules located in the atmosphere. The spectrum of the color blue is much more readily visible to the human eye therefore that is why when we look at the sky we mainly see the color blue. At sunrise and sunset the light from the sun has a harder time getting through the atmosphere to our eyes therefore light is scattered towards the red end of the spectrum.(Why the Sky is Blue)

Mirages are another effect that can be explained due to physics. Mirages happen when there are two different temperature layers in the air. There is a hot layer of air and a cold layer of air. Because there are two layers there is a boundary between them which can refract light it creates an image. An example of when this can occur is on asphalt in the summer time.(Mirages1)

Works Cited

http://acept.la.asu.edu/PiN/rdg/rainbow/rainbow.shtml#top

http://acept.la.asu.edu/PiN/rdg/sky/sky.shtml

http://physics.bu.edu/~duffy/PY106/Eye.html

http://www.unmuseum.mus.pa.us/mirage.htm

Winter Break Blog: Rianbows, Mirages, Color of Sky

Physics Explained

Rainbows:

White light is a combination of many colors; a rainbow is when the white light has all of its colors separated. To form a rainbow the white light from the sun hits the raindrops and then reflects off the side of the raindrops and exits into your eyes. Each angle has a different distinct color.

Color of Sky:

The sky is scattered sunlight whose particles are smaller than the wavelength of the light. The sky is actually not only blue, it has many other colors in it as well; just the eye are the most sensitive to blue and not so much violet, and most of the light in the sky is violet and blue, therefore, creating the blue image in the sky. A further explanation as to why the sky is the color blue is because of the preferential scattering of short wavelength blue light compared to the scatter of long wavelength of red light, which is proportional with the gases in the atmosphere to the scattering of light by individual molecules (Rayleigh scattering).

Mirages:



The effect that two air levels at different temperatures is a mirage. Light can be refracted; considering there are two different temperatures of air and cold air is denser than hot air is. The specific type of mirage known as the oasis mirage happens when the air just about the ground is heated by the ground. A real example of this is when you believe to see the asphalt ground as water. This appears like this because the black color of the asphalt heats up the above air fast, which creates the refraction of the light from the sky. Light is refracted many times if there are numerous amounts of layers of different temperature air. As a result to this, natural objects can appear to look like city buildings. An example of this type of mirage is the Alaskan City Mirage.

Works Cited

"Light and Optics." Patterns in Nature 2000 March 3, 2008 http://acept.la.asu.edu/PiN/rdg/rainbow/rainbow.shtml#top.

"What Causes a Rainbow?." 2000 March 3, 2008 http://www.howstuffworks.com/question41.htm.

"Blue Skys and White Clouds." Patterns in Nature 1999 March 3, 2008 http://acept.la.asu.edu/PiN/rdg/sky/sky.shtml.

"Mirages in The Sky." 1998 March 3, 2008 .

Physics Blog: Winter Break

Rainbows, Mirages, Sky

Rainbows, Mirages, and the color of sky at dawn and dusk are more than just a pretty site for one’s eye. They have a lot of physics behind them that can explain their nature and being. The leprechaun does not just find the pot of gold at the end of a rainbow, but can be enlightened by the physics that causes such a miracle. The refraction of various lights causes the colors that encompass our world. Many physics concepts such as dispersion, refraction, and others involve the explanation of the formation of rainbows, mirages, and the sky.
The topic of rainbows is very interesting, because the concepts involved are quite complex. Think about the time one sees rainbows; it is always after a rainstorm, light rain, or some type of precipitation. This is one of the factors that help form the rainbows. The sunlight that forms rainbows bounces off the water vapor and particles in the air and reflect back into your eyesight. The white light from the sun is not only reflecting off the water, but it is also refracting and dispersing from the drops. Only the refracted rays are actually seen in the eyes, because they form the colors and rainbow. Specifically, every raindrop shows one color of the rainbow. For example, every light reflected at 42 degrees is seen as red light. The various colors that make up a rainbow spectrum; red, orange, yellow, green, blue, indigo, violet, each have specific and different refractions. For example, blue light bends or refracts more so than the green light. The green light then refracts more than the red light, and so on. The prism that makes up the rainbow split into different colors, which form due to the refraction techniques. “Each rainbow is your own,” this is because each rainbow looks different compared to the rainbow seen from a friend’s companion (Rainbows: Lights and Optics).
Another physics phenomenon includes the mirages in a sky. Two layers of air at different temperatures form a mirage. Cold air is denser than hot air, therefore the boundary between the two layers can refract light. The easiest and most commonly known mirage is the pond of water in the desert. Examples of various mirages include a band of marching soldiers on a mountain, certain UFO spottings, and of course the water in the desert. Mirages on top of water are seen when the air temperature is much warmer than that of the water. When there are several boundaries between the air layers, the more light is refracted and the more complex the image appears. Some claim to have seen castles, cities, and buildings refracting off a cliff. There are many mirages seen in the desert as well as the Arctic especially. The smoothness, shape, and amount of boundaries all are factors of what make the mirage (Krystek).
Mirages are not in fact optical illusions but real physics phenomenon, and can be photographed. This chart explains the classification of a mirage: IMAGEEEEE? The refraction of a mirage includes terrestrial refraction, inside the atmosphere and astronomical refraction, beyond the atmosphere (Young). The various forms of refraction and the boundaries between airs form the physics marvel of a mirage.
Lastly, the final physics wonder seen throughout the atmosphere is why the sunset and sunrise are full of colors. The sun formulates this because of the way the optics of the human eye work. When the sun is rising or setting, it has to travel through much more atmosphere to reach the human eye. Most of the blue light scatters in other direction, leaving mostly the red and orange side of the spectrum to reach our eyes. The human eye relies on refraction and lens to see the images of the world. Because the red and blue lights are on the opposite side of the light spectrum, they come to they eye at different times. Due to the refraction of our eye, blue light is almost never seen, because it refracts in too many different directions. The red, orange, and yellow light is more direct and can be seen from far away at sunrise or sunset (Polarization).
Physics is a science full of interesting and incredible marvels. The science of rainbows includes dispersion, refraction, and reflecting. Mirages are all about boundaries between airs that create a real photographable image. Finally, the sun, the thing that lights the world is perceived through our eye due to the different wavelengths of color. Overall, each one of these topics includes a lot of interesting physics that make up their formation.










Works Cited
Krystek, Lee. "Mirages in the Sky." Mirages in the Sky. 1998. 1 Mar 2008 .
"Light and Optics." Patterns in Nature. 26 Dec 1999. Department of Physics and Astronomy: Arizona State University. 1 Mar 2008 .
"Polarization." Polarization; And the Human Eye. 1999. 4 Aug 1999 .
Young, Andrew T. "Introduction." An Introduction to Mirages. 2008. .

Human Eye Paper

The eye is a very interesting and complex organ within the human body. Its main function is to provide sight.

The outermost layer of the eye is called the sclera and it maintains the shape of the eye. The front clear part of this is called the cornea. Extraocular muscles are the muscles that move the eye and these are attached to the sclera. All light must pass through the cornea first and then moves onto the choroid which is the second layer of the eye. This part contains blood vessels that supply blood to the different parts of the eye and contains two structures called the iris and ciliary body. Within the iris there are two muscles the sphincter and dilator. The dilator muscle makes the iris smaller and pupil larger which allows more light into the eye. The sphincter muscle makes the iris larger and pupil smaller which allows less light into the eye. Pupil size can change from 2 millimeters to 8 millimeters on average and when the size of the pupil changes, it changes the amount of light that enters the eye 30 times. The innermost layer of the eye is called the retina and this is the light-sensing portion of the eye. Contained in this layer are rod cells, which are responsible for vision in low light, and cone cells that are responsible for color vision and detail. The macula is located in the back part of the eye in the center of the retina. In the center of the macula is the fovea centralis and this part contains only cones as it is used for seeing fine details. The retina also contains a chemical called rhodopsin, known as "visual purple." This chemical converts light into electrical impulses that the brain then measures as vision. Retinal nerve fibers are connected at the back of the eye, forming the optic nerve, which sends the electrical impulses to the brain. The optic disk is where the optic nerve and blood vessels exit the retina. This is a blind spot on the retina because there are no rods or cones. Yet we are unaware of this blind spot because each eye covers the blind spot of the other eye. This is some of the basic anatomy of the human eye. (Bianco, M.D. 2)

There are many infections, diseases, etc. that cause vision problems or even blindness. Glaucoma is when drainage of an aqueous humor which is produced in the ciliary body and then drained through the canal of schlemm is blocked. The conjunctiva, which keeps the eye moist, can have an infection called conjunctivitis also known as pink eye. The eye is protected from injuries by a bony cavity called the orbital cavity and eyelids do this by blinking. Eyelashes and eyebrows also protect the eye from particles that may harm it. Nearsightedness, also known as myopia, is when a person is able to see near objects well but has difficulty seeing objects that are farther away. Farsightedness, also known as hyperopia, is when a person is able to see distant objects well but has difficulty seeing objects that are closer. Astigmatism is an uneven curvature of the cornea that causes distortion in vision. The older we get the more the lens becomes less elastic and loses its ability to change shape. This is called presbyopia. It is more noticeable when we try to see things up close, because the ciliary body must contract to make the lens thicker and the loss of elasticity prevents the lens from becoming thicker. This causes us to lose our ability to focus on certain objects. A cataract is cloudiness in the lens that blocks light from reaching the retina and can be corrected with surgery. Trachoma is an infection caused by an organism called Chlamydia trachomatis and is disease is the most common cause of blindness is the world, however is rare in the United States. Other causes for blindness include vitamin A deficiency, tumors, strokes, neurological diseases, other infections, and hereditary diseases. (Bianco, M.D. 9, 10, 12)

The eye relies on refraction in order to focus on various objects. Refraction takes place by the aqueous humor, which is a liquid on top of the lens. Light is refracted as it comes into the eye by the liquid, is then refracted more by the lens, and then more by the vitreous humor, which is a jelly-like substance located in the space between the lens and the retina. The lens is critical in creating a sharp image so it can adjust quickly when focusing objects at different distances and this process is known as accommodation. (Polarization 1)

The eye is a very interesting and vital organ in the human body. It works to help us focus in on images at various distances. By this we are able to observe the world around us and enjoy its beauty.

Works Cited

Bianco, M.D., Carl. ""How Vision Works"." How Stuff Works. 1998. 2 Mar 2008 http://health.howstuffworks.com/eye4.htm

unknown, unknown. "Polarization; and the Human Eye." University. 2 Mar 2008 http://physics.bu.edu/~duffy/PY106/Eye.html

The Electromagnetic Spectrum by Austin

The Electromagnetic Spectrum

Electromagnetic waves occur when there is a disturbance in the electric force field, which is made up of charged particles like electrons and protons. Different kinds of waves are determined by how long their wavelengths are. A wavelength can be determined by how many times a wave completes its cycle over a set period of time. The shorter the wavelength, the more powerful the wave is and the more energy it has.

The longest wavelengths, like TV and radio waves can be about 20 meters or longer. They are used to transport information without using wires, and can even go through space. They work by sending electric currents through conductors called antennae which send and receive the wave impulses. These radio waves can communicate with submarines under water, create the radio we can listen to, and communicate into outer space.

There are also microwaves, which are between a millimeter and a meter long. We all think of the microwave ovens we use in the kitchen, but this is only one of their uses. They care also used in radar that can detect the range and speed of things. They are also useful for GPS and navigation systems.

Infrared waves are about 0.00001 meters. Infrared means “below red” in latin, because they are directly below visible light on the electromagnetic spectrum. They can be used for surveillance, night vision, tracking, wireless communication, and they are used extensively in weather forecasting.

Visible light is about 0.0000006 meters long in wavelength. The colors we see also have a spectrum of their own: red, orange, yellow, green, blue, indigo, violet. They also go in order of wavelength, with red being the longest and violet having the shortest length.

Ultraviolet, or UV rays are about 0.00000003 meters, and are usually associated with exposure to the sun. They can cause cancer, blisters, or scars if exposed too long. They are used in medicine for killing bacteria and viruses and sterilize equipment. They are also used to make blacklights, and experiments show that birds and insects can see UV light.

X-rays which are about 0.0000000009 meters, are used in medicine to photograph the bones and internal organs of a patient. And the highest energy waves are gamma which are produced through high energy protons or radioactive decay. They are so powerful that it takes large mass objects to absorb their energy. They can easily cause damage to living tissue, and are the most dangerous in a nuclear explosion.

Wednesday 2/13

So today we did not have a snow day (depressing) but we did have physics!! We learned about defraction today which is a change in the direction upon transmission into a new medium if the wave changes speed or strikes the boundary obiquely (this means not eqal to 90 or 0 degrees, basically not perpendicular). Refraction can occur through different media, such as water, glass or air.

Mr. Wirth described a very handy analogy that would help us remember refraction. Imagine a line of soldiers marching from a road onto sand (a slower medium). As they approach the sand and begin walking across it the line will bend. Wavefronts also bend and get closer.

The rules for refraction as follows:
1. If the speed decreases at the interface than the wave bends toward the normal; it forms a smaller angle with the normal.
2. If the speed increases at the interface than the wave bends away from the normal; it forms a larger angle with the normal.

The absolute index of refraction is a ratio of the speed of light in a vacuum to the speed of light in a medium, because it is a ration it is dimensionless. The reference table can be used for a particular frequency. Its symbol in n and the equation is n=c/v. Another equation used when there is two different mediums is n2/n1=v1/v2=wavelength1/wavelength2.

ALSO....we learned tody that Jess Dulski's father is a dentist. If your having problems with your teeth or think you may have a cavity contact Dr. Dulski immediately.

Julia Davis is also a champion sudoku player. She spends her time in class perfecting her skill so for fuure reference DO NOT interrupt her when she is trying to complete her sudoku puzzles. ( This should also be followed when she is applying her make-up. she has to look beautiful for her fans)

But anyways..BAGELS IN 2 DAYS AND BREAK!!!

2-12-08 class

Wavefronts and Rays
-use a ray to indicate the direction of motion of a wave front
-rays of a circular wavefront are radial lines
-rays on a plane wavefront are parellel lines
-use to track the direction of waves

Reflection
-a wave striking a surface at an angle
-latin "a bending back"
-the change in direction of a wavefront at an interface between 2 differences media so that the wavefront returns to the medium from which it originated

Law of Reflection
-angle of incidence= angle of reflection

Types
-law of reflection is always obeyed
-Specular-smooth surfaces, produces image of the source ex. mirrors

Physics Notes 2/5 by Jess

Diffraction- wavelength vs sive of opening
small opening-more diffraction
large-less diffraction

Resonance- increased amplitude of oscillation of a mechanical system when subjected to vibration at or near its own natural frequency

(insert Julia's "Oh, S***!" here)

Natural Frequency- frequency at which objects tend to ocillate when disturbed
-if objects are excited at natural fequecny, the aplitude of vibration will increase
-Electrical circuits also exert electricity
Example: pushing a swing, or musical instrument