By Christopher Scott LaRoche
completed in partial fulfillment of the requirements for
Teaching High School Physics
Physics 301
Fall 1998
Illinois State University
Carl J. Wenning, Instructor
Unit Overview
This physics class will consist of primarily high school seniors with the prerequisite classes of Algebra I and Algebra II. Algebra II may be taken concurrently with Physics. The textbook for the class will be Physics-Itís Methods and Meaning (1992 Alexander Taffel, PHD). Midway through the semester the students will be entering the domain of optics. The unit will begin with the behavior and properties of waves. With the background information of waves weíll begin studying the nature of light. The unit will end with reflection and refraction through the use of mirrors and thin lenses.
The unit will provide the student with content knowledge which will help them understand the world around them. They will be able to see a magnifying lens and describe to their parents how it works. The unit will also provide the student with the tools to solve a variety of problems. They can use Snellís law to calculate the angles of incidence and reflection, or they can use the thin lens equation to determine the location of an image. Also the unit will hopefully change the students beliefs that physics is hard. A hands on technique will allow the students an opportunity to discover concepts on their own. By letting the students explore for themselves they may gain an appreciation toward physics.
The understanding of optics is crucial to not only the scientist but also to the student and the society as a whole.
Optics is important for the student because it helps them explain the world around them. People donít think about how they are able to see they just know that they can. Optics reveals the mysteries behind the nature of light and how it interacts with the human eye. Therefore, knowing the concepts and how to apply them can help a student ìseeî the world around them.
Throughout history societies have benefited with the development of optical devises. Glasses have allowed people with vision problems to see clearly again. Telescopes have helped the people explore the universe, while microscopes have helped view the microscopic world. Knowing how to use the optical equipment is important, but knowing the physics behind it offers the person the chance to better the optical technology.
The understanding of optics is crucial to the scientist. One of the quickest ways to collect data is through sight. One can generalize and describe just by looking, thus the importance of optical satellites. Scientists are reaching new bounds in the galaxy and being able to see the other planets reveals volumes of information. However, this would be useless if the telescopes didnít work. Therefore, scientist must know about optics to create a working space telescope.
Content Outline
Energy Transfer By Waves
Transverse and Longitudinal Waves
Frequency, Wavelength, and Speed
Waves undergo reflection, refraction, interference, and diffraction
Nature of Light
Light as a form of energy
Photoelectric Cell
Ignition of paper with a magnifying glass
Speed of Light
Albert Michelsonís Method
Ole Roemerís Method
3*108 m/s
Light travels in straight lines
Intensity of Illumination
Inverse Square Law of Illumination
Reflection
Law of Reflection
Wave Theory explains the Law of Reflection
Mirrors
Flat, Concave, Convex, and Spherical
Virtual and Real Images
Ray Diagramming for image location
Spherical Aberration
Refraction
Snellís Law
Measuring the Index of Refraction
Measuring the speed of light in a substance
Total Internal Reflection and the Critical Angle
Total Reflecting Devises
Prisms
Fiber Optics
Lenses
Types- Concave and Convex
Definitions:
Convergent and Divergent
Focal Point and Focal Length
Principal Axis
Real and Virtual Images
Object and Image Distances
Magnification
Ray Diagramming
Thin Lens Equation
Applications of Lenses
Eye
Eye Glasses
Camera
Microscope
Telescope
Magnifying Lens
Diffraction
Huygenís Principle
Single Slit Diffraction Patterns
Effects of slit width on diffraction
Interference
Constructive and Destructive
Thomas Youngís Double Slit Experiment
Measuring Wavelength
Band Width
Diffraction Grating
Coherence of Light
1. Lasers
Major Objectives
After the student has finished with the optics unit they should have learned the content knowledge objectives. Some of the content knowledge objectives include:
After the optics unit the students will also be able to demonstrate the following process skills:
Many students enter the physics course with the idea that physics is hard and nothing but number crunching. It is no lie that a physic course is challenging nor is it a lie that there is a lot of number crunching. However, once a student overcomes the challenges and understands the importance of calculations they will soon see how important physics is in everyday life. Material should be delivered in a hands on fashion to where the student can explore and discover the underlying concepts. Once students see how much physics is surrounding their everyday lives they will grow even more curious. Soon the student will hunger for more information and realize that many questions can only be answered through equations and number crunching. Once the student has reached this level physics will become fun.
Hopefully I will be able to offer hands on activities that spark the curious minds of students. I want to point out all the applications optics has in the everyday world. Hopefully students will begin to bring in outside resources and together as a class figure out how something works. For instance, it would be great if a student brought in a flashlight and asked how it worked. As a class we could analyze the flashlight and discuss how it uses concave mirrors to focus incandescent light.
All in all, I hope the students see past the number crunching and say that physics is challenging but itís not impossible. I want them to accept the challenge and leave with skills and attitudes that they can solve any problem.
Alternative Conceptions
Dorothy Gabel points out in her book that alternative conceptions in optics stems
from the fact that most students donít have a conceptual model of the nature of light. (Gabel, p.182) Other research also shows that students have many myths about the behavior of light. For example, students tend to believe that most if not all of the light which enters the eye is refracted in the lens. However this is not the case because most of the refraction occurs at the air-cornea interface. (Jewett 1994, p.352) The former belief leaves the student with the misconception that vision underwater is blurry. This statement is true to those that have perfect vision because the water-cornea interface have much less of a difference in the index of refraction than just an air-cornea interface. The little difference in the index of refraction means that the light will only slightly refract causing the light rays to focus behind the retina. On the other hand, some one would be able to see clearly underwater if they were near-sighted. Once again the water-cornea interface will lower the index of refraction, but this time the light rays will be focused on the retina. This phenomenon occurs due to the fact that near-sighted people focus light in front of the retina so with a lower refraction in water the rays would be focused on the retina. Thus the near-sighted person would be able to see clearer underwater than out of water if they didnít have their glasses on. (Jewett 1996, p.284)
One of the most helpful aids used to understand the nature of light can also be a leader in providing misconceptions. Teachers always perform ray diagrams using an arrow with the base on the principal axis. They show the three main rays used to generalize ray diagramming by starting the light rays at the head of the arrow. This leaves the students with the idea that light rays only travel from the top of an object. They miss the idea that light rays come from all directions. Quickly we see that a simple aid becomes a crutch which supports alternative conceptions. Therefore teachers must pay careful attention to all areas of physics that may produce misconceptions in the classroom. (Jewett 1996, p.367)
Classroom Methods
(1) Inquiry lesson
Author: LaRoche, Christopher Date: 11-9-98
Course Name: Physics Grade Level: 12th
Unit Title: Optics Concept: Focal Length of Thin Convex Lenses
Objective:
The student will be able to, generalize the characteristics (similarities and differences) of convergent lenses, explain the concept of focal length based on experimentation, and give examples of common instruments that work through the use of thin lenses.
Content:
Convergent lenses have similarities and differences in physical characteristics to other convergent lenses.
Similarities
The three convergent lenses have the same diameter and circumference.
All three lenses are colorless.
All three lenses are smooth to the touch.
All three lenses are convex.
Differences
Some lenses are thicker in the middle than the others.
Some lenses are almost flat or not bowed out in the middle.
Convergent lenses have a unique focal length.
Parallel rays of light refract through the lens and converge at the focal point.
Thicker lenses have shorter focal lengths than their thinner counterparts.
Instructional Activities:
1. Ask the class what are the physical characteristics of the lenses in
front of them and what type of lenses they are.
2. By placing one lens up to their eye theyíll find that everything around
them is blurry.
3. Holding the lens slightly above some letters on the paper and then
raising the lens the students will see a magnified image.
4. Students will place a lens on a blank sheet of paper and then slowly
raise the lens until a clear image of the ceiling is formed on the paper.
Students will measure and record the height it took to obtain the most
focused image. The measured height will determine the focal length of
the lens.
(4) 5. Students will hold the thick lens up to their eye while holding the
thinnest lens in front of the former. Moving the thin lens forward will
magnify a distant object just like a telescope.
(4) 6. Students will hold the thick lens up to their eye while holding the
thinnest lens in front of the former. Moving the thin lens forward will
magnify a distant object just like a telescope.
7. Spend some time discussing what will be done for tomorrows class.
(5) Evaluation: Evaluate by asking the students to generalize the properties
of the lenses which will ultimately determine their
understanding of the focal length.
(45)
Materials: Three convex lenses of 5cm, 10cm, and 20cm focal lengths,
rulers, pencils, and handout/procedures. (see
Attachment A)
Sources: Self Produced Inquiry Lesson
(2) Inquiry lesson
Author: LaRoche, Christopher Date: 11-9-98
Course Name: Physics Grade Level: 12th
Unit Title: Optics Concept: Ray Diagramming
Objective:
The students will be able to, gain a concrete understanding of focal point, generalize the behavior of light rays before and after coming into contact with a convex lens, and use the generalization obtained from experimentation to find an image of an object by way of ray diagrams.
Content:
Parallel rays of light refract through a convex lens and cross on the principal axis.
The focal point is determined through the use of parallel rays.
B. Every lens has its own unique focal point.
Guidelines or Generalizations can be determined which is the basis of ray diagramming.
Light rays from the left of a convex lens parallel to the axis are refracted through the lens and pass through the focal point.
Rays coming through the focal point, on the left side of the lens, emerge from the lens parallel to the axis.
Ray diagramming can be used to locate the image of an object without the
use of lenses and light sources.
Instructional Activities:
(5) 1. Ask the class if they can describe the focal point of a convex lens
based on the previous inquiry lesson. Then ask if the idea of a focal
point makes sense to them.
(2) 2. Help the students set-up the plexi-glass lens and the light source.
(5) 3. The students will see that the parallel light rays refract in the lens and
cross the principal axis. The students will be asked what they just
found (focal point).
4. Students will then have to trace the path of a light ray traveling
through a point (O) and focal point (F). Both points will be located to
the left of the lens. The students will then label the light path they just
traced as (1).
(2) 5. Students will then examine their sketches to determine if any of the
light rays from step three above intersect with (1). Students will
designate the other intersecting ray as (2).
(10) 6. Students will write up the generalizations they have just observed.
7. Students will use the newly found generalizations to find the image
location of an object in the shape of an arrow. The procedure to
accomplish this will be left up to the students.
(--) 8. If time permits, the students will attempt to perform ray diagramming
on the board. Otherwise weíll begin class tomorrow with ray
diagrams.
(5) Evaluation: Evaluate by asking the students to determine the
generalities necessary to ray diagram, and to then apply this
knowledge to solve image location problems.
(45)
Materials: Two light sources which produce a narrow beam of light,
large plexi-glass lenses (convex), grid paper, colored
pencils, rulers, and blackboard optics kit (not necessary).
(see Attachment B)
Sources: Self Produced Inquiry Lesson
Demonstrations
ìSlinkyî Wave
Transverse and Longitudinal Waves
Have a student hold one end of a long slinky while the teacher holds the other end. The teacher will begin to wave their end back and forth to represent transverse waves. The teacher can then compress a portion of the slinky and let go. The slinky will produce a concrete example of longitudinal waves.
(Cutnell/Johnson, p.483)
Single and Double Slit Interference
Constructive and Destructive Patterns
Aim a laser beam through a single or double slit. (The demonstration should be away from the students as a safety consideration.) Students can see the patterns on the wall which then can be used to show that the distance between fringes decreases with an increase in slit separation.
(Freier/Anderson, O-32 & O-33)
Prismís, Squares, and Circles
Refraction
Shine a laser through a glass square and note how the beam refracts. Do the same with the prism and circle shaped glass. This demonstration is best done with a blackboard optics kit.
(Kutasov, p.277)
Prism Mirror
Critical Angle
Shine a laser beam through a prism until the critical angle is found. The students will see that the critical angle will produce total internal reflection.
(Griffith, p.321)
Pinhole Camera
Image Production and Ray Diagramming
Punch a hole in the bottom of a Styrofoam cup and make a one inch hole in the bottom of another cup. Tape a sheet of thin paper over the end of one of the cups and then attach the two cups together (top to top). Now cover the cups with aluminum foil, but leaving the holes at both ends open. Place your eye up to the one inch hole and point toward a lit candle. The students will be able to see the image of the candle on the thin paper. From here the students can make several observations about the image size and location.
(Edge, 6.08)
Magic Trick
Image location with Concave Mirror when object is at Center of Curvature.
Get a black box with a light fixture attached to the top of the box. Another fixture should be placed directly underneath the other fixture on the inside of the box. Place a bulb in the fixture which is located inside the box. An 18 inch concave mirror should be position so the light bulb sits at its center of curvature. When the light is turned on the image will be located at the top fixture. A true optical illusion is produced.
(Freier/Anderson, O-10)
Diffraction Grating
Composition of Light
Give the students a sheet of diffraction grating. When the students look at an incandescent light source they will be able to see that the light is composed of many colors (ROYGBIV).
(Self Produced)
Photoelectric Cell
Light Energy Converted to Mechanical Energy
Place an incandescent bulb next to a photoelectric bulb. When the light is turned on the photoelectric bulbs filament will begin to spin.
(Self Produced)
Two Sunglasses Better Than One?
Polarization
Ask the students what will happen if you placed two polarized sunglasses together. Then ask them to predict what will happen if you rotate one pair of sunglasses. This is an interesting introduction to polarization.
(Self Produced)
Car Mirrors
Properties of Convex Mirrors
Bring in some old side mirrors from a car. Ask the students to explain why the mirror states, ìObjects In Mirror Are Closer Than They Appear.î Let the students play around with the actual mirror to see if they can come up with some answers.
(Taffel, p.369)
Water Drop Optics
Positive and Negative Lenses
Place a piece of clear tape at the end of a straw. Now cut the straw so it is only 1 cm long at the taped end. Place the straw on a piece of news paper and fill the straw with water using another straw. Make sure the water forms a large meniscus and then look through it. The students will see that the meniscus represents a convex lens which produces a magnified image. As water slow drains out the meniscus will change shape into a concave lens. If the students look through the straw now they will see that the image is reduced in size.
(Edge, 6.03)
Laboratory Activities
Reflection of Light
Acquaint the student with basic properties of reflection and the location of images.
The students will first need to become proficient with the use of image locating. Place a piece of cardboard under a blank sheet of paper. Place a line horizontally across the blank sheet. Next place a pin at the middle of the line but about 5 inches up the paper. The student will then place the cardboard at eye level along with a ruler. By looking down the edge of the ruler the student will be able to see the pin, do this on the left side of the paper below the horizontal line. Once the student has the pin is in line of the ruler edge they should mark a line against the ruler. The student then can do the same line of sight procedure on the right side. Once they have done this they can extend their lines back until they cross. The lines should intersect directly at the pin. This is how the students will find the image by line of sight.
Next the students will get a clean piece of paper and make the same horizontal mark across the paper. At this horizontal line place a flat mirror facing you. Place a pin about an inch away from the front of the mirror. Starting at the left side of the mirror the students can use the line of sight technique by drawing in lines which travel to the image on the mirror. Repeat the process on the right side of the mirror. Now that the students have two lines they can remove the pin and mirror. Extend the two lines until they cross, the point of intersection is the image location. Quickly the students will see that the image is behind the mirror or is virtual. The angle of incidence and angle of reflection can even be found if the students are curious. Finally, other types of mirrors can be used with the line of sight method to find the image location.
(Greeseth/Jesse, E.1.a)
Principles of Refraction
Acquaint the student with basic properties of refraction and the location of images.
Students will use the line of sight method described in the previous experiment to find the image location in rectangular shaped piece of glass. Place a piece of rectangular glass in the middle of a clean piece of paper. A piece of cardboard should be placed under the paper as described in the last experiment. Place two pins about 2 inches away from each other at a 45( angle from the top of the glass rectangle. Starting at the bottom right side of the glass use the line of sight method until the two pins are lined up one behind the other. (This may take some moving around.) Once the two pins are lined up draw in a line next to the ruler. Trace the outline of the rectangle glass block. Remove the glass and pins from the paper. Draw a line from the two pins to the top surface of the rectangle, then extend the line of sight line to the bottom of the rectangle. Connect the point of intersection at the top of the rectangle to the bottom intersection point. The student will be able to see that the light refracted in the medium and they can then measure the angles of incidence and refraction. If time permits other shapes can be used as well.
(Greeseth/Jesse, E1.b)
Convergent Lenses (Student Directed)
Determination of object placement to achieve specific image requirements.
In previous class work the students developed the necessary conclusions to help them direct this experiment. The students will be asked the following questions:
Where does the object have to be located to produce an image that is inverted and smaller?
Where does the object have to be located to produce an image that is inverted and is the same size as the object?
Where does the object have to be located to produce an image that is inverted and enlarged?
Where does the object have to be located to produce an image that is erect and enlarged?
Where does the object have to be located to produce no image?
The students will be required to back all of their answers with measurements taken in the lab setting. For example, all focal points should be determined, the object and image distances determined, and the object and image heights should be determined for each question.
The students will be given an optics bench with all the necessary equipment. To get the students started they will be advised to read each question thoroughly and as a team list possible solutions. Then starting at the top of their list perform the idea to see if it works. If the first idea doesnít work then they should go to the next until the question is answered. Since this is a student directed experiment the teacher will leave the procedures up to them. However, the teacher should walk around and give any help that they deem needed. It is the teachers role to be the guide to keep the experiment progressing. We donít want any students to be left with the feeling of helplessness.
(Self Developed)
Safety Considerations
The principal has many responsibilities in the school. One of the many responsibilities that the principal faces is the safety of the teachers and students in the classroom. They are responsible to make sure that there is adequate lighting and heating. They are also responsible to ensure that the laboratory space is large enough to permit proper conduct of experiments. The principal is also responsible to make sure that there are two unobstructed exits remote from each other, and that the lab tables are made of non-combustible material. The principal should also make sure that there are master cut off switches to both the gas and electric outlets. All outlets are to be grounded, fire extinguishers present, face/eye showers present, and safety showers present wherever there is a potential for chemical spills. If any of the safety features are flawed then it is the responsibility of the principal to find the means to correct them promptly. Finally the principal is required to make sure that regular safety inspections are performed. (NSTA Subcommittee on Safety, pp.1-2)
The science department chairperson is responsible to make all teachers and assistants aware of hazards in science classes. They are responsible to notify the principal of any safety measure flaws. They are also required to supply a first aid kit in each science laboratory. The chairperson should make sure that all dangerous chemicals are properly stored and locked. They should also inspect laboratory equipment to make sure that none is faulty which can become a safety hazard. Finally the chairperson is required to see that each room has a metal or earthware waste jars and that all waste is properly disposed of. (NSTA Subcommittee on Safety, pp.2-3)
The teachers main responsibility is to inform the students of the proper safety procedures. These procedures are then to be posted in the room for any student to review if necessary. The teacher must also inform the students at the beginning of each laboratory exercise the safety issues associated with it. (NSTA Subcommittee on Safety, pp.3-4)
One of the main safety issues one must deal with in Optics is electricity. Many of the times students will be using a light source which must be plugged in. If the wires are worn the student may receive a shock. The shock can be as minor as a sting or it can range from a burn to death. In order to prevent electrical accidents the teacher must replace worn cords, use grounded 3-prong plugs, and notify students of any hazards that may be present. (AAPT Committee on Apparatus, pp.3-5) Electric safety is not the only teachers concern in optics. Teachers should be very careful when dealing with lasers. The teacher should inform the students that they should never look into a laser beam because it can cause retinal damage. If the teacher does allow the students to use a laser then it is highly advised that they keep close supervision. In most cases it is easier and safer for the teacher to demonstrate with a laser and let the students use an incandescent light source. (AAPT Committee on Apparatus, pp.7-8)
Most of the demonstrations and laboratory exercises should not pose as any safety hazard. However there is a potential that the pinhole camera may produce some problems since a candle is used as an object. In order to make the demonstration safer the teacher could use a light bulb in a darkened room. I also believe that broken glass should also be considered a possible safety hazard. Since the students will be working with glass lenses there is a good chance that some will be dropped causing sharp edges. If such a situation happens then the teacher should quickly and properly dispose of the lens. In the demonstrations a laser is used, thus that is why I had the teacher demonstrate its uses. Having the teacher demonstrate with the lasers takes the safety issue down to a minimum. With the teacher using the laser they must be aware that they could accidentally shine the laser into the eyes of the students. This is why I stated that the teacher must perform all demonstrations with a laser away from the students. Finally, the teacher should make sure that all potential hazards are brought to the attention of the students before the experiment and demonstrations. Hopefully this will help eliminate any hidden dangers from arising.
Special Student Needs
The student which has a disability most readily seen in a physics classroom is one which is a paraplegic. A paraplegic person is one who has paralysis of two limbs due to spinal disease or injury. The most common form of paralysis is from the waist
down, therefore paraplegic students will be confined to a wheel chair.
B. Since a paraplegic student is confined to a wheel chair they may find that mobility
in the classroom may be a problem. Although there are laws for handicap
accessibility I have noticed in my observations that these laws are being pushed to
the limits, thus there is a chance that the classroom may not be well suited to
accommodate a wheel chair. For example the aisles may be to narrow and the desks
may not have enough under room for the wheel chair. Most demonstrations are done
in the front of the room on top of the desk, this may be a problem for someone who
is sitting low to the ground. If paraplegic students are unable to participate and see
the demonstrations then they may just tune out which will directly effect their
learning ability.
C. It is apparent that some measure must be taken to insure an equal learning experience
for a paraplegic student. Elimination of physical barriers should be addressed first.
Desks that are adjustable and aisle spacing large enough to accommodate a wheel
chair should be acquired. Demonstrations should be brought down to a level which
can be seen by the student. If the demonstration is potentially dangerous then video
tape it and show it to the whole class. Group work shouldnít be a problem as long as
the desks are adjusted to fit a wheel chair underneath. Lab work should also pose no
problem if the table and equipment is adjustable. If there is any other special needs
of the paraplegic student I simply will ask them and I will inquire within one of the
Special Education teachers.
D. Many times a teacher has a gifted student in their class. If this happens I would offer
the student the opportunity to do research into the physics of the ìHubbleî telescope.
The research would incorporate documentation of time and resources used. The
gifted student will have to prepare a report and poster board which will be used to
make a class presentation. The project will be offered as extra credit and it will also
be offered to the entire class. I would offer the project to the entire class to avoid
fairness issues, however it is most likely that only the gifted student will take on the
project. Note: Certain criteria must be met in order to receive credit. This prevents
everyone from doing a quick job to get some extra credit.
There is a chance that a student with limited English proficiency may enter my class.
The first thing I would do is talk to the Special Education teacher again because they would be able to direct me with what I should do to help the student in the class room. If the student falls behind due to the language barrier I may have to help them outside the class along with someone who is proficient in their language.
Student Assessment
After all the laboratory exercises have been performed I would assess their process skills. I would evaluate the students by placing them in front of an optics bench with an assortment of equipment. Each student will be given two questions which will be drawn out of a hat. After the student has their questions they will have to manipulate the equipment to achieve the desired result. Once they have answered the first question they must call me over to inspect their work. This will assess the students ability to determine variables, recall information from class/lab, construct hypotheses, and experiment until the questions are answered.
Example
Question--Where does the object have to be located to produce an image that is inverted
and smaller? (Measurements Must Be Included)
Question--Where does the object have to be located to produce an image that is inverted
and is the same size as the object? (Measurements Must Be Included)
To assess a students scientific disposition I would have them prepare a short report. The report would require some research, decision making and value judgements. The amount of work the student placed into the report would also be an indicator of their dispositions toward optics. For example, if they didnít do much work then they probably donít care for the assignment. On the other hand, the students that put all they have into it would reveal that they really enjoy the concepts and course.
Example
You are a member of a NASA research team that just developed a new optical satellite which is powered by a mini-nuclear reactor. The nuclear reactor has been outfitted to maintain a high planetary orbit. Normally maintaining such an orbit wouldnít be a problem however, the orbit that the satellite will follow will be on the outermost boundary of Earthís gravitational pull. Thus the nuclear reactor will occasionally be used as a propulsion method. The concerns that surround this project are as follows:
Are the costs of the project worth the scientific knowledge gained?
Even with the nuclear reactor will the optical satellite be able to maintain itís orbit?
If there is an accident aboard the satellite it will begin a descent toward earth. Upon striking the earth the nuclear reactor housing will rupture causing a massive radiation leak. Is the potential of a radiation leak on earth worth the scientific knowledge possibly gained?
There is also the chance that the optical satellite may not work at all. Is there any more room above the Earthís atmosphere for space garbage?
These are some of the questions that you as a researcher must consider before asking for more grant money. There are scientific and moral judgments that must be made. So what will you decide, go with the project or call it quits. Write up your research and conclusion in a small report.
Students have different types of learning styles. The three most common learning styles are descriptive, inductive, and deductive. Since there are different types of learners then there should be different types of assessment.
Assessment of Descriptive Learners
Give the student a set of convex lenses and ask them to determine their general properties. Then have the student play with the lenses until they can create a microscope, telescope, and a magnifying lens. The student should write down all observations and procedures which answered the questions.
Assessment of Inductive Learners
The student will work with the descriptive learner to determine the general properties of the lenses. The inductive learner will then explain what the general properties of the convex lenses. The inductive learner will then draw out and describe the lens arrangement which create a microscope, telescope, and magnifying lens for the rest of the class to see. If the class has any questions the inductive student will be there to try to answer.
Assessment of Inductive Learners
The deductive learner will also be given a set of convex lenses. They will be asked to determine the lenses general properties and determine a method to find the focal point. Once the student knows the focal point of the lenses they will be asked to use this and the idea of ray-diagramming to explain the physics behind microscopes, telescopes, and magnifying lenses.
Congruence With State and National Goals
Illinois State Goals for Learning (ISGL)
I believe that after the students have made it through the optics unit their scientific literacy will be heightened. Not only will they be able to recognize and define scientific terms but they will also be able to place the terminology in the everyday world. Being able to use the knowledge gained in a physics class outside of class correctly is an increase in scientific literacy. For example, students will be able to relate image location and focal point to near and far sightedness.
After student complete the student guided satellite project they will hopefully have a better understanding of the social and environmental implications and limitations to technology. The students will see that sometimes the technological advancement may not out weigh the environmental damage possible sustained. They may realize that the advancement of technology may cost more than the advancement is worth.
One Illinois State Goals for Learning states that students use principals of scientific research to create a simple research project. I have provided an opportunity for the students to research the physics behind the Hubble telescope. I will show the students how to go about doing the research, but then the students will be left on their own to apply the principals of research.
Illinois State Goal 11.B.5.b states, ìSelect criteria for a successful design solution to the identified problem.î I have given the student the necessary equipment to solve problems dealing with image and object location. The students will need to set-up the experiment and then decide if their idea answers the question. If they find that the question is not answered then they must prepare a new design. The students will develop processes, techniques, and methods to solve the optics problem. ( HYPERLINK http://www.isbe.il.us/ils/scg11.html http://www.isbe.il.us/ils/scg11.html)
National Science Education Standards (NSES)
The NSESís Teaching Standard A states, îTeachers of science plan an inquiry-based program for their students.î I believe that my unit plan does reflect a considerable amount of inquiry based work. For example, the students will be undergoing team work that incorporates a self discovery of optics phenomenon. They will slowly work with lenses until they discover the concepts of focal point and focal length.
The NSESís Teaching Standard B states, ìTeachers of science guide and facilitate learning.î In order to be a guide to student learning I have incorporated a student directed experiment. Here the students must work together and share the responsibility for their learning. While the students are producing their own procedures I will be able to offer helpful hints to prevent the students from feeling lost.
The NSESís Teaching Standard C states, ìTeachers of science engage in ongoing assessment of their teaching and of student learning.î I have incorporated a peer-evaluation to help assess the amount of effort and work each student placed into the student directed experiment. I also have students doing a report on the physics behind the Hubble Space Telescope. These are just some of the ways that Iíll be assessing the students, plus Iíll be able to reflect on their grades to see where I am lacking in my teaching ability.
The NSESís Teaching Standard D states, ìTeachers of science design and manage learning environments that provide students with the time, space, and resources needed for learning science.î Having done a safety assessment of my demonstrations and experiments I believe that the students will have a safe working environment. The students will have as many tools and resources available which I can muster up. I will also try to point out everyday phenomena that are directly related to optics, this is why I chose to use Hubble and other optical devises in my problems and examples.
The NSESís Teaching Standard E states, ìTeachers of science develop communities that reflect the intellectual rigors of scientific inquiry and the attitudes and social values conducive to science learning.î I have tried to account for different learning styles in my classroom. My goal is that the students will respect the diverse ideas and skills of their peers since everyone is different in some way. I believe that students can learn a lot from their peers so I have tried to team up mixed ability groups. With the mixed abilities I hope that the gifted students will help the less gifted. I want all the students to help each other gain skills and attitudes to succeed in the science classroom.
( HYPERLINK http://www.nap.edu/readingroom/books/nses/html/3.html#ts http://www.nap.edu/readingroom/books/nses/html/3.html#ts)
Project 2061ís Benchmarks for Scientific Literacy
After reading the Project 2061ís Benchmarks I realized that under The Physical
Setting, Part F most closely related to my unit plan. Here students are to know that visible light is one type of electromagnetic wave and that all electromagnetic waves move at the ìspeed of lightî. At the beginning of the optics unit the students will be instructed about the nature of light. Here they will be introduced to the idea that light is composed of waves and that they travel at the speed of light. (see Section II.) I also will be showing the students that waves can superpose each other, bend around corners, reflect off surfaces, and refract in different mediums. All of this content will be covered and demonstrated throughout the optics unit.
( HYPERLINK http://project2061.aaas.org/tools/benchol/bolframe.html http://project2061.aaas.org/tools/benchol/bolframe.html)
Philosophy Of Teaching Statement
I believe that all students have the right to a fair and equal education. Students
who are gifted should be encouraged to continue in their excellence, but at the same time help those who donít have the same abilities. Instead of splitting the ability levels in the class they should be brought together. Students can learn a lot from their peers so the gifted student may be able to explain the course information to a non-gifted student in a way which I couldnít. I also believe that to prevent the separation of ability levels I must not favor the students that have little to no problem understanding the information. I must also focus on the lower ability students because if I donít then they will only fall further behind.
I also believe that understanding and sensitivity must be shown to all students in order to maintain an environment conducive to learning. I, as a teacher, must be able to place myself into the shoes of the students to better understand what they are going through. I cannot forget that every student has outside influences that affect their potential to learn. Since everyone is different a better understanding of these differences will ultimately improve my teaching and the students learning ability.
I believe that rules should be set and followed by everyone. I further believe that since everyone has outside influences that may affect their classroom abilities, flexibility must also be incorporated. Hopefully a mutual respect will not allow the flexibility to be taken advantage of.
I also believe that it is my responsibility as a teacher to provide an environment which promotes an interest in science and education in general. I want to provide the resources needed to solve real life problems, problems which will leave the student an attitude that they can accomplish anything. The environment that I provide will hopefully leave the student with intellectual enthusiasm and courage to be creative.
Ultimately I believe that my teaching philosophy is ever changing because as my experience in the teaching field continues I will encounter situations that will affect my personal philosophy.
References
AAPT Committee on Apparatus. (1978) Teaching physics safely. Washington, DC: Author
Aarons, A.B. (1990) A guide to teaching introductory physics teaching. New York, NY: John Wiley & Sons.
Cutnell, Johnson. (1995) Physics. New York, NY: John Wiley & Sons.
Edge, R.D. (1987) String & Sticky Tape Experiments. College Park, MD: AAPT
Freier, Anderson. (1996) A Demonstration Handbook for Physics. College Park, MD: AAPT
Gabel, Dorothy. (1994) Handbook of Research on Science Teaching and Learning. New York, NY: Macmillan Publishing Company
Greenseth, Jesse. (1985) Experiments for General Physics. Champaign, IL: Stipes Publishing L.L.C.
Griffith, T.W. (1998) The Physics of Everyday Phenomena. Burr Ridge, IL: WCB/McGraw-Hill
(http://www.isbe.state.il.us/ils/scg11.html) Illinois State Goals of Learning from the Illinois State Board of Education
Jewett, J.W. (1994) Physics Begins with an MÖMysteries, Magic, and Myth. Boston: Allyn and Bacon
Jewett, J.W. (1996) Physics Begins with Another MÖMysteries, Magic, and Myth, and Modern Physics. Boston: Allyn and Bacon
Kutasov, Shoma. (1978) Physics Demonstrations. Los Angeles, CA: Penn Books
( HYPERLINK http://www.nap.edu/reading http://www.nap.edu/readingroom/books/nses/html3.html#ts) National Science Education Standards
NSTA Subcommittee on Safety. (1978) Safety in the secondary science classroom Washington, DC: Author
( HYPERLINK http://project2061.aaas.org/tools/benchol/bolframe.html http://project2061.aaas.org/tools/benchol/bolframe.html) Project 2061 Benchmarks for Scientific Literacy
Attachments
(A)
A Study of Thin Lenses
Experiment O.1
-Convergent Lenses-
Name: Partner: Date:
Part I
Pick up any lens and note its physical characteristics.
For example: Itís thicker than the other lenses.
Do the same for the other lenses.
What do these lenses have in common?
Pick up the thickest lens and put it next to your eye. Look through it at a distant object and describe what you see.
What do you have to do in order to see clearly through the lens?
Repeat with the other lenses.
What happened to the object you were looking at in #3 when you were able to see it clearly?
Did this happen for all the lenses?
Place a lens on your paper and move the lens toward you until you can see clearly. What happened?
What common household item does this remind you of?
Try your best to answer why the results from #4 differ from #5?
Starting with the thickest lens, place it on your paper. Position your paper and lens so it is facing a light, the ceiling should work fine. Slowly lift the lens off the paper and watch the spot where the lens was. What do you see?
Do this with all the lenses and note any differences.
As you lifted the lens off the paper you started to get an image. Then there was a distance in which the image was the clearest. The clearest image produced means that it is in ?
Did you notice that each lens produced an image at different heights from the paper? What was the distance from the paper to the lens (in cm) that gave you the clearest image?
Since this distance produces the most focused image what shall we call this
distance?( )
(B)
A Study of Thin Lenses
Experiment O.2
-Convergent Lenses-
Name:
Date:
Part I
Tape two pieces of paper together as instructed by the teacher.
Place the flat sides of the lens together. What kind of lens have you just made?
Position the lens so the seam running down the middle of the lens is on a vertical line.
Place the light source at any point to the upper-left of the lens. Mark the point where the light comes out as (O). Align the light beam parallel to the horizontal lines. Why did I ask you to position the light beam like this?
What happens to the light beam when it strikes the surface of the lens?
Trace in the light rays as best as you can. Now repeat step four but this time do it at the lower-left of the lens. What happened to the light beam when it strikes the surface of the lens?
Trace in the light ray. Do the two light rays cross?
If they do cross mark their intersection as (F). What do you think this is point of
intersection is called?
Will all parallel light rays cross at this point?
Measure distance from (F) to the surface of the lens. (Ask for help if you need.) What value did you get in centimeters?
Place a point (F) on the other side of the lens at the same length as measured in #7. Can we place a focal point (F) on both sides of the lens?
Explain why?
Now that we have a focal point on each side of the lens I want you to place your light source back at the point (O) at the upper-left of the lens. This time position the light beam so it is going through both point (O) and the left focal point (F). What happened to the light beam?
Draw in the path of the light beam with a colored pencil. Using the same colored pencil label this path as (1). Does the path of this light beam cross with any other light ray you have previously drawn in on the right side of the mirror?
Retrace the other light beam that crosses (1) with a different colored pencil and label
it (2).
Now that you have two light rays with different colors I want you to discuss and record any generalities which may be used with these rays. In other words, what happened to these light rays and will this behavior always hold true?
What you have just accomplished is commonly referred to as Ray Diagrams. You are probably thinking, ìWhat good does this do us?î The wonderful thing about ray diagrams is that the technique can be used to find any image!
Image Location
Part II
Tape two new pieces of paper together like you did before. Position the lens on the paper as described above also. Determine where the focal points (F) are and mark them on your paper.
Draw an arrow on left side of the lens with the base of the arrow on the principal axis. Call the arrow your Object. Using your newly acquired knowledge from Part I determine where the Image would be.
Describe what you did below.
Can you find the image of the arrow if the base of the arrow was below the principal axis? (Sketch it out)
The beautiful thing about Ray Diagrams is that you can do them by hand. You donít even need the light source and lens to determine where the image will be. Lets do some on the board.