Optics: An Educator - PDF document

Optics: An EducatorÕs Guide With Activities in Science and Mathematics Optics: An EducatorÕs Guide With Activities in Science and Mathematics X rays are a high-energy called the Advanced X-ray AstrophysicsFacilityÐAXAF) the worldÕs mostfrom space. Astronomers must haveEarthÕs atmosphere absorbs and blocks NASA NASA Projects, MSFC, OpticsObservatorythan the Hubble Space Telescope andMSFC. The observatoryÕs telescope wasRay Calibration Facility. vOptics: An EducatorÕs Guide With Activities in Science and Mathematics EG-2000-10-64-MSFC Hubble Space Telescope into orbit onApril 26, 1990. With its vantage pointabove EarthÕs atmosphere Hubble hasJupiter, and storms on Saturn, all with Aft ShroudDouble Roll-outSolar Array (2) hyperbolic-shaped mirror. The design NASA NASA Projects, MSFC, Optics Telescope Optics: An EducatorÕs Guide With Activities in Science and Mathematics EG-2000-10-64-MSFC The futuristic idea of a small laser-propels the lightcraft into the sky.Improving Observatory Alignmentnear Ft. Davis, Tspectroscopy. It has a special mirror Next Generation Space Telescope NASA NASA Projects, MSFC, Optics viiOptics: An EducatorÕs Guide With Activities in Science and Mathematics EG-2000-10-64-MSFC Space Station Windows NASA NASA Projects, MSFC, Optics activity for its effects on the EarthÕsupper atmosphere. It uses a Wolter Optics: An EducatorÕs Guide With Activities in Science and Mathematics EG-2000-10-64-MSFC Classroom ActivitiesActivity 1:Reflection of Light With a Plane (Flat) MirrorActivity 2:Reflection of Light With Two Plane MirrorsActivity 7:Exploring Diffraction With a SpectroscopeActivity 10:Light and Color-Color SpinnersActivity 11:Light and Color-FiltersActivity 12:Light and Color-Hidden MessagesActivity 13:Simple MagnifiersActivity 1:Reflection of Light With a Plane (Flat) MirrorActivity 2:Reflection of Light Withe Two Plane MirrorsActivity 3:Reflection of Light With Two Plane Mirrors-Double SidedActivity 5:Making a PeriscopeActivity 6:Constructing a SpectroscopeActivity 7:Exploring Diffraction with a SpectroscopeActivity 10:Light and Color-Color SpinnersActivity 12:Light and Color-Hidden MessagesActivity 13:Simple MagnifiersActivity 4:Making a KaleidoscopeActivity 5:Making a PeriscopeActivity 8:Diffraction of Light by Very Small AperturesActivity 9:Discovering Color With a PrismActivity 14:Focusing Light With a LensActivity 15:Building a TelescopeActivity 16:Building a MicroscopeActivity 17:Interference FringesActivity 18:Polarization of Light Optics: An EducatorÕs Guide With Activities in Science and Mathematics EG-2000-10-64-MSFCx $   3+% :.3= 7,=   4   ,,&#x;&#x;&#x;&#x;&#x-231;&#x.700;
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$2"6&#x;&#x;&#x;&#x;&#x-231;&#x.700;64  07 6 2 Optics: An EducatorÕs Guide With Activities in Science and Mathematics Activity/LessonCommunicationProblem SolvingConnectionMeasurement1.Reflection/Plane Mirror2.Reflection/2 Mirrors3.Reflection/Double Mirrors4.Making a Kaleidoscope5.Construction of a Kaleidoscope6.Making a Periscope7.Constructing a Spectroscope8.Exploring Diffraction9.Electromagnetic Spectrum10Diffraction of Light11.Discovering Color/Prism12.Fabrication of a Prism13.Color Spinners14.Filters15.Hidden Messages16.Simple Magnifiers17.Focusing Light With a Lens18.Building a Telescope19.Building a Microscope20.Construction of a Micoscope21.Interference Fringes22.Polarization of Light 4 Optics: An EducatorÕs Guide With Activities in Science and Mathematics Introduction to ColorColor is a part of the electro-magnetic spectrum and has alwaysexisted, but the first explanation ofcolor was provided by Sir IsaacNewton in 1666.Newton passed a narrow beam ofsunlight through a prism located ina dark room. Of course all the visiblespectrum (red, orange, yellow, green,blue, indigo, and violet) was displayedon the white screen. People alreadyknew that light passed through aprism would show a rainbow or visiblespectrum, but NewtonÕs experimentsshowed that different colors are bentthrough different angles. Newton alsothought all colors can be found inwhite light, so he passed the lightthrough a second prism. All the visiblecolors changed back to white light.Light is the only source of color.The color of an object is seen becausethe object merely reflects, absorbs, andtransmits one or more colors thatmake up light. The endless variety ofcolor is caused by the interrelationshipof three elements: Light, the source ofcolor; the material and its response tocolor; and the eye, the perceiver of color.Colors made by combining blue,yellow, and red light are calledadditive; and they are formed byadding varying degrees of intensityand amounts of these three colors.These primary colors of light arecalled cyan (blue-green), yellow, andmagenta (blue-red).Pigment color found in paint, dyes,or ink is formed by pigment moleculespresent in flowers, trees, and animals.The color is made by absorbing, orsubtracting, certain parts of thespectrum and reflecting or transmittingthe parts that remain. Each pigmentmolecule seems to have its owndistinct characteristic way of reflecting,absorbing, or transmitting certainwavelengths. Natural and manmadecolors all follow the same natural laws. 6 Optics: An EducatorÕs Guide With Activities in Science and Mathematics MirrorImage of Object(Virtual Image) Object The angle of incidence is equal tothe angle of reflection.Reflection in a Flat MirrorEvery object we see has many raysof light coming from it either byreflection or because it is a lightsource such as a light bulb, the Sun,a star, etc. Each point on that objectis a source of light rays. In theillustration below, the tip of the arrowis used as an example of a point on theobject from which rays of light wouldbe coming. As the rays from the object SmoothReflectingi = Angle of Incidencer = Angle of Reflectionir are reflected by the mirror, thereflected rays appear to come from theimage located behind the mirror at adistance equal to the object's distancefrom the mirror. The image is called avirtual image since the rays do notactually pass through or come fromthe image; they just appear to comefrom the image as illustrated below. 8 Optics: An EducatorÕs Guide With Activities in Science and Mathematics In the case where the object islocated between the focal point andthe mirror, such that the objectdistance is less than the focal lengthof the mirror, a virtual, upright, andenlarged image is obtained. This isthe case when looking at yourself ina concave Òmake-upÓ mirror, which isdescribed below.A ray (1) appearing to come fromthe focal point strikes the mirror andis reflected parallel to the optical axis.A ray (2) parallel to the optical axis isreflected by the mirror so that it goesthrough the focal point. A ray (3) strikingthe mirror at the optical axis is reflectedso that the angle of reflection is equalto the angle of incidence.The ray diagram below uses threereflected rays to illustrate how theimage can appear to be enlarged andupright. The image formed is a virtualimage.Convex MirrorThe image formed by a convexmirror is virtual, upright, and smallerthan the object. This is illustrated bythe ray diagram on the following page.The diagram depicts the three raysthat are discussed in the followingparagraph.A ray (1) parallel to the optical axisis reflected as if it came from the focalpoint (f). A ray (2) directed toward thefocal point is reflected parallel to theoptical axis. A ray (3) striking themirror at the optical axis is reflectedat an angle equal to the angle ofincidence. f(1)(3)(2)ObjectImageOpticalAxis 10 Optics: An EducatorÕs Guide With Activities in Science and Mathematics Converging LensWhen using a thin lens, that is, thethickness at the center of the lens isnot too great, a thin lens mathematicalapproximation can be used. Thisapproximation assumes the bending oflight occurs in one plane inside thelens.A ray of light coming from a verydistant object, such that the ray isparallel to the optical axis, will be bentby refraction at the two surfaces of thelens and will cross the optical axis atthe focal point (f) of the lens, as seenin the illustration below. A ray passingthrough the center of the lens willpass through the lens undeviated. ObjectImagef (1)(2) The size and location of an imageformed by a lens can be found by usingthe information from these two rayswhich is shown in the illustration below.The following illustration depictstwo rays, which are defined in thefollowing text. A ray (1) parallel tothe optical axis passes through thefocal point (f). A ray (2) passingthrough the center of the lens isundeviated.The image is real, smaller than theobject, and upside down. If a piece ofpaper is placed at the image location,a real image can be seen on the paper.An example of this is taking a picturewith a camera, where the photographicfilm is located at the image position. OpticalAxisFocalLengthf Ray #1Ray #2 12 Optics: An EducatorÕs Guide With Activities in Science and Mathematics 14 Optics: An EducatorÕs Guide With Activities in Science and Mathematics EG-2000-10-64-MSFC Procedures1. Stand the mirror at 90 degrees tothe surface of the table.2. Stand the two wooden blocks onthe ends. Position them parallel toeach side of the mirror and 10inches from the face of the mirror. Start Here 12"
12" Mirror TileCardboardWooden Blocks Tracing Pattern 3. Place the cardboard horizontallyacross the top of the two woodenblocks. Place a paper tracingpattern on the flat surface betweenthe two blocks of wood.4. Place your finger or pencil at thestarting point on the pattern.5. Look only in the mirror and trace thestar pattern found on page 5. Nowtrace the swirl pattern also on page 5. 16 Optics: An EducatorÕs Guide With Activities in Science and Mathematics EG-2000-10-64-MSFC Observations, Data, and Conclusions1. What did you learn after tracingthe two patterns?2. What information did your eyesgive you?3. What information did your brain orbody give you?4. Where did the hand in the mirrorseem to be located when you lookedin the mirror?5. Is it harder to trace a pattern withyour finger or with a pencil? Why?6. What characteristic of light did youlearn about when you did this activity?7. After completing these questions, drawsome designs of your own. Exchangeyour designs with another studentand trace their designs. 18 Optics: An EducatorÕs Guide With Activities in Science and Mathematics EG-2000-10-64-MSFC Procedures ProtractorTape 1.Place the mirrors at a 90-degree angle.2.Place yourself in front of the mirrors.3.Look into the mirror and follow theinstructions. All instructions shouldbe followed while looking into themirror, not at your body.A.Raise the right hand that yousee in the mirror.B.Turn your head to the left.C.Touch your right ear with yourleft hand.D.Look into the mirror and winkyour left eye.E.Raise both hands with yourpalms facing the mirror..Touch one little finger to thethumb on the other hand.G.Bring both hands togetheruntil your fingers touch.H.Raise the left hand with thepalm facing the mirror and theright hand with the palmturnedaway from the mirror.I.Touch your right shoulder withyour left hand.J.Choose a partner and give fiveinstructions of your own. Observations, Data, and Conclusions1.What did you observe during thisactivity?2.What information did your eyesgive you?3.Why was this activity difficult?4.What characteristic of light did thisactivity use or demonstrate? 20 Optics: An EducatorÕs Guide With Activities in Science and Mathematics EG-2000-10-64-MSFC Procedures1.Place the protractor on a table andstand the two mirrors on top of itat a 90-degree angle. The mirrorsshould be placed so that you canreadily measure the angle as youopen and close the mirrors.2.Place the mirrors at a 90-degreeangle. How many mirrors do yousee? How many complete images doyou see? How many parts of imagesdo you see? Record your observationsin the chart on page 21.3.Change the mirrors to a 10-degreeangle and count the whole imagesand the parts of images that yousee. Repeat step 2.4.Continue to change the degrees ofthe angle from 0 through 180degrees and repeat step 2.HINT: When you look into the mirrors,place your face between the twomirrors or as close to the edges aspossible. Keep your face perpendicularto the space or hinge between the twomirrors. ProtractorTape 1.Make your observations as youcomplete the table on the followingpage. (Refer to question No. 4 below.)2.At what degrees or angles do youseem to see whole images and nopartial images?3.How does the number of degreesseem to be related to the numberof mirrors that you count?4.Using the following formula,compute each angle measured andcompare your answers to what yousee in the mirror. Because you areusing simple materials, yourobservations may differ slightlywith the computations.Number of images observed inmirror equals 360 degrees dividedby angle indicated on theprotractor.Example: 360 = 4 imagesPerform the math computationsand complete the table in questionNo. 1 above.5.Are the number of observed imagesand the computed math answers thesame? Why or why not? Observations, Data, and Conclusions 22 Optics: An EducatorÕs Guide With Activities in Science and Mathematics EG-2000-10-64-MSFCMath Computations: 24 Optics: An EducatorÕs Guide With Activities in Science and Mathematics EG-2000-10-64-MSFC Procedures1. Place the three mirrors together asshown, using the long side of eachmirror. Put a few pieces of tape onthe backs of the mirrors to holdthem together.2. Put two of the rubber bands aroundthem to hold them securely together.3. Use this simple kaleidoscope to dothe following activities.A.Hold the kaleidoscope in your handand look through it at objectsaround the room.B.Hold the kaleidoscope above thewhite cardboard and look downinside it. Put some object such as acoin, or the small pieces of coloredpaper in the resealable bag (keepthem in the bag) on the whitecardboard inside the kaleidoscope.Observe the images reflected in themirrors. Small Objects Rubber Observations, Data, and Conclusions1.How many images did you see?2.Did the images appear to be thesame size as the object?3.How were the objects oriented withrespect to the reflected images? 26 Optics: An EducatorÕs Guide With Activities in Science and Mathematics EG-2000-10-64-MSFC PVC pipe 4 inches in diameter and Cardboard endpieceFoam rubberpackingThree mirror tilesglued at 60 anglesCardboard eyepiecePVC pipe 4 inches in diameter and Cardboard endpieceFoam rubberpackingTwo mirror tiles gluedat 20 anglesCardboard endpiece 7.Position this circular cardboardpiece into the end of the PVC pipeand glue it with white glue to formthe eye piece of the kaleidoscope.8.Now cut another circular cardboardpiece to fit the opposite end of thepipe. In the center of the cardboardcut a triangle with three 60-degreeangles.9. Match this triangular opening withthe opening formed by the threemirrors and use the white glue toglue the cardboard into place.It is also possible to make akaleidoscope using two mirrorspositioned at a 20-degree angle. Youmay fill in the third side with a pieceof mirror tile. Experiment withvarious angles of the mirrors andlocations of the eyepiece holes.Kaleidoscopes made with smallerangles are more interesting. 28 Optics: An EducatorÕs Guide With Activities in Science and Mathematics EG-2000-10-64-MSFC ProceduresInsert both flat mirrors into theperiscope viewing tube as shown. Themirrors must be facing each other.When the mirrors are insertedcorrectly each mirror will be restingon the wooden supports. As eachmirror is inserted, place a small pieceof Scotch tape over the mirror slots onthe outside of the viewing tube. Holdthe periscope so the mirrors are restingon the wooden supports, then lookthrough it.NOTE: The mirrors will fall out if youturn your periscope upside down. Object 2"3"2"3" Cut-out squareof cardboard Observations, Data, and Conclusions 1.Draw a diagram of the path a rayof light follows as it travels from anobject, through the periscope, andinto your eye.2.Do you think the periscope wouldwork if the mirrors were at someangle other than 45 degrees?A periscope can easily be madefrom materials that you can find athome. The drawing above gives you anexample to use. Mirrors of any sizewill do, as long as they are flat. 30 Optics: An EducatorÕs Guide With Activities in Science and Mathematics EG-2000-10-64-MSFC Procedures1.Make or adapt a box that is about 10inches long, 6 inches wide, and 2inches deep. The box must have atight lid.2.Use a black marker and color theinside of the box and lid.3.Choose one end of the box andmeasure 1/4 inch from the corner.WITH ADULT HELP ORSUPERVISION, cut out a 1-inchsquare hole.4.Next cut a piece of diffractiongrating 1Ð1/2 inches square.5.Cut a frame of manila paper for thediffraction grating. The sidemeasurements should be 1Ð1/2inches square, and insidemeasurements for the hole in theframe should be 1 inch square.6.Frame the diffraction grating andtape it inside the box to cover the1-inch square hole cut in step No. 3,with lines of the diffractiongrating vertical.7.Directly opposite the diffractiongrating on the other end of the box,measure and mark 1/2 inch from thecorner of the box and 1/4 inch fromthe bottom. WITH ADULT HELP ORSUPERVISION, cut a hole 1-inchhigh and 1/2-inch wide.8.Cut a rectangle of manila paper 1Ð1/2inches by 2 inches. In the center ofthe manila rectangle, cut a smallrectangular hole 3/4-inch high and1/4-inch wide.9.WITH ADULT SUPERVISION,break the razor blade into twopieces along the long hole in theblade. ce t h e s h a rp ed g es o f t h e b l a d e t og t h e r t o f o rm a l o n g n a w s l i 10.Mount the razor blade slit so thatthe long slit is parallel to the linesof the diffraction grating.11.WITH ADULT SUPERVISION,center the slit in the double-edgerazor blade over the opening in thelarge manila rectangular frame.Tape pieces of the blade in place.12.Tape the framed razor blade to theoutside of the box on the endopposite from the diffraction grating.13.Place the lid securely on the box.Find a light source. Aim the razorblade at the light and look throughthe diffraction grating.14.Observe the emission spectrumemitted by the light source. Diffraction GratingManila Paper1 1/2"
1 1/2"Hole1"
1"Lid Razor Blade Manila Paper1 1/2"
2" Hole 1"
1 1/2" 32 (Students should color these boxes with their crayons.) ROGBIVRedOrangeGreenBlueIndigoViolet YYellow ProceduresUse a spectroscope and look atdifferent kinds of light. View bulbswith different gases inside. Observations, Data, and Conclusions1.Observe each source of light. Explainwhat you see.2.Observe the colors. Start with thefirst color on the left and list themin the table in the order that yousee them.3.When you look at the different lightsources through the spectroscope,observe the stripes of color. Do theyfade or blend into each other?Describe the bands of color.4.Does each light source produce thesame group of colors or spectrum?5.Each group of colors for each differentlight source is called the emissionspectrum for that source. How are thespectra or groups of colors alike?Different?6.Why are the groups of color for eachlight source different? ColorsLight Source 34 The ElectromagneticFor hundreds of years, scientists believedthat light energy was made up of tinyparticles which they called Òcorpuscles.Ó In the1600Õs, researchers observed that light energyalso had many characteristics of waves.Modern scientists know that all energy isboth particles, which they now call photonsand waves.Photons travel in electromagneticwaves. These waves travel at differentfrequencies, but all travel at the speed oflight. The electromagnetic spectrum isthe range of wave frequencies from lowfrequencies (below visible light) to highfrequencies (above visible light). (Seefigure below.)The radio wave category includes radio andtelevision waves. These low-frequency wavesbounce off many materials.Microwaves pass through some materialsbut are absorbed by others. In a microwaveoven, the energy passes through the glassand is absorbed by the moisture in the food.The food cooks, but the glass container isnot affected.Like other wavelengths, infrared or heatwaves are more readily absorbed by somematerials than by others. Dark materialsabsorb infrared waves while light materialsreflect them. The Sun emits infrared waves,heating the Earth and making plant andanimal life possible.Visible lightwaves are the verysmallest part of the spectrum and are theonly frequencies visible to the human eye.Colors are different within this category,ranging from the red wavelengths, whichare just above the invisible infrared, toviolet. Most of the SunÕs energy is emittedas visible light.The Sun also emits many ultravioletwaves. High-frequency ultravioletwavelengths from the Sun cause sunburn.X rays can penetrate muscle and tissuebut are blocked by bone, making medical anddental x-ray photographs possible.Gamma-ray waves, the highest frequencywaves, are more powerful than x rays and areused to kill cancerous cells.The atmosphere protects Earth fromdangerous ultraviolet, x-ray, and gamma-ray radiation. 1 km1 cm1 cm 36 Optics: An EducatorÕs Guide With Activities in Science and Mathematics EG-2000-10-64-MSFC ProceduresUse both diffraction screens, one at a time.1.Hold one diffraction screen by itsedges and place it in front of youreyes. Look through it at a pointsource of light several feet awayfrom you.2.Slowly rotate the diffraction screenwhile continuing to look through itat the light source.3.Repeat steps 1 and 2 with the otherdiffraction screen. Rotate Observations, Data, and Conclusions1.Draw or describe the pattern youobserved through each diffractionscreen the first time you looked atthe light source.2.How did the pattern change aseach diffraction screen was slowlyrotated? You can observe the same squareaperture diffraction pattern using apoint source of light at home. Finda window with sheer curtains andobserve a street light through thecurtains. This experiment will need tobe done at night when the street lightis lit. To observe the diffraction pattern,turn the room light off and look at thestreet light through the sheer curtain.The street light serves as the lightpoint source and the curtain providesthe diffraction screen. 38 Optics: An EducatorÕs Guide With Activities in Science and Mathematics EG-2000-10-64-MSFC Procedures1.Hold the small prism with onefinger at the top and one finger atthe bottom. Position the prism 2 to3 inches in front of your eye. Lookthrough one side of it in thedirection of the light source asshown below.2.First, look at the incandescentlamp. Observe the colors that arevisible as you view this lamp.3.Next, view the fluorescent lampand then the cadmium lamp. (Thekinds of light source may vary.)4.Record your observations in thenext section. Prism Fluorescent Lamp Light SourceColors Observations, Data, and Conclusions1.Observe the colors from the threedifferent light sources and listthem in order in the chart below.Start with the first color on the leftand list them as you see them.(Hint: ROY G. BIVÑred, orange,yellow, green, blue, indigo, violet)2.What differences and/or similaritiesdid you observe in each light sourcewhen looking through the glass,plastic or acrylic plastic?3.Were the colors always in the sameorder?4.Were the colors always in bands?5.Did the bands always form thesame shapes?Hint:An artificial light sourcewill not transmit the completespectrum unless it is a white lightsource. 40 ¥ acrylic plastic about one-half inch thick.¥ Hacksaw with fine blade or band saw,very fine sandpaper (400 or 600 grit,possibly available at auto paint stores orauto body repair shops), very fine file,craft felt, silver polish, one small boardwith two tacks (optional). Junior Home Scientist Project ProceduresFrom Acrylic Plastic 1.Place the plastic in a bench vise andcut it to shape with a fine-bladehacksaw. The angles should be asnear 60 degrees as possible. File thecut edges smooth.2.Put a piece of fine sandpaper (400or 600 grit) on a flat surface. Rubthe cut face or edge of the prism onthe sandpaper holding the face or cutedge flat against the paper in orderto get a nice flat face. Continuesanding and using finer and finersandpaper until the surface issmooth, free of scratches, and hasa translucent appearance.3.Now the plastic is ready to polish tomake the surface transparent. Thepolishing pad is a 2-inch 4-inchpiece of craft felt. Tack the felt to aboard or hold it stretched on a flatsurface. Wet the felt with water andput a small amount of silver polishon the felt. Rub the plastic on the feltstrip. Expect to spend one-half houror more to polish a single edge orface of the plastic. When finished,wet the plastic with water and pat itdry so the surface will not be scratched. 42 Optics: An EducatorÕs Guide With Activities in Science and Mathematics EG-2000-10-64-MSFC Procedures Observations, Data, and Conclusions1.Color the circles with the magicmarkers. You may color each sectiona different color or draw a colorfuldesign.2.When you have colored the circle onboth sides, punch two holes in thecenter of the circle about one-half toone-quarter inch apart.3.Cut a piece of string about 36 to 48inches long. Thread the stringthrough the two holes and tie thetwo ends together.4.Now hold a piece of the string in eachhand and twist it. Pull the string andmake the paper circle spin.1.Observe the pattern on thespinning circle. What did you see?2.What colors did you see?3.Did the colors seem to mix andbecome other colors?4.How can you make green?5.How can you make orange?6.How can you make gray or white?7.How can you make brown?8.Can you make stripes? How?9.What else can you make? Keepexperimenting! 44 Optics: An EducatorÕs Guide With Activities in Science and Mathematics EG-2000-10-64-MSFC Procedures Observations, Data, and ConclusionsPlace a filter in front of the lightsource. Combine two colored filters.Now combine three colors. Experimentwith many different combinations.1.What colors can you make with twodifferent filters?2.What colors can you make withthree different filters?3.How many different colors can youmake?4.What did you learn about colorfilters? Source 46 1.Using at least 3 different magicmarker colors, draw a design. Thinkin terms of space and astronomydesigns.2.Use magic markers to draw moredesigns, be sure to include at leastone hidden message in yourdesigns. Can you hide three or moremessages in one design?(Students should use a space orastronomy word as their hiddenmessage and then draw designsover it.)3.View the design through severalfilters. Procedures Observations, Data, and Conclusions1.When you viewed the designswithout a filter, what did you see?2.What did you see when you looked atyour design with each colored filter?3.What did you see when you usedtwo different filters together?4.Why did you see different thingswith each different filter?5.If possible, exchange designs withanother person and read theirsecret message. 48 Optics: An EducatorÕs Guide With Activities in Science and Mathematics EG-2000-10-64-MSFC Procedures Observations, Data, and Conclusions1.Place a piece of transparent tapeacross the opening of the slide orcardboard. Wet one finger and placeone small drop of water onto the tape.2.Position the water drop above thenewspaper or numbers. Can youread the letters or numbers?3.Continue to experiment. Use a bigdrop of water. Use a tiny drop ofwater. Hold the drop very close tothe letters and words. Move thedrop slowly away from the words.Keep experimenting.4.Now place the edges of the bottlesclose to the words. Do all of thebottles magnify? Do some of themmagnify? Do they magnify better ifyou put water in them? Experimentwith bottles of all shapes. Do somejars of water reverse letters?Water Drop Magnifier1.What did you see when you lookedthrough the drop of water?2.Could you read the letters? Did theletters and numbers appear larger?3.How did you focus the water dropmagnifier?4.Which water drop magnified more,the large drop or the small drop?Why? Hint: How does the size ofthe water drop effect the way lightis bent or refracted?5.What shape bottle or jar magnifiesbest?6.What parts of bottles magnify best?7.Do these bottles or jars magnifybetter with water in them?8.Why do bottles magnify objects? Cardboard orSlide Frame Transparent 50 Optics: An EducatorÕs Guide With Activities in Science and Mathematics EG-2000-10-64-MSFC Procedures ProceduresUsing both lenses, one at a time,complete all the activities in then complete 1.Experiment with the lenses. Holdeach lens above a surface such asyour hand, the writing on this page,the fabric of your clothes, etc. Adjustthe lens until the surface is in focusand you can see the object clearly. Atthis point, we are using the lens asa magnifier. Details of the objectshould be sharp.2.With the 12-inch ruler, measure thedistance from the edge of each lensto the imagethat you havein focus onthe paper, asshown. Thisdistance willbe known as for lens No.1 and Dlens No. 2.3.Calculate an estimatedmagnification power for each lens.The magnification of a lens can beexplained simply as how many timeslarger the lens makes the objectappear. To perform this calculation,assume that the nearest distance 12 1110 at which you can see objects clearlyis 10 inches. Use the estimatedfocal length measurement of eachlens, Dand D, that was measuredin the procedure above. Observations, Data, and Conclusions1. Using the following equation, calculatean estimate of the magnification foreach lens: = Ñ(inches) near distancefor clear vision(inches) estimatedfocal length of lens2. Using the previous equation,compute the magnification () ofeach lens using the distance () foreach lens. for lens No. 1 for lens No. 2 10 = for lens No. 1 10 for lens No. 23.Which lens has the greatermagnification? 52 3.If you found two clear images, whatwas different about them? Why werethere two images? (optional)4. Using the following equation,calculate the focal length of each lensusing the measurements that youhave just made.The following equation describes how thefocal length are related for a lens.=focal length=object distance=image distance 1 1 1Use this equation twice, once for each lens.Focal length lens No. 1centimeters (cm)Focal length lens No. 2centimeters (cm) 54 Optics: An EducatorÕs Guide With Activities in Science and Mathematics EG-2000-10-64-MSFC ProceduresThis telescope will be constructedusing the same lenses that were usedin the experiment named, ÒFocusingLight With a Lens,Ó page 49.1.The mailing tubes will be the bodyof the telescope with the smallerone sliding inside the larger one.The length of the assembledtelescope will be a little longer thanthe sum of the focal lengths of thetwo lenses. Add the value of thefocal lengths of the short and longlens together. Divide that length bytwo and then add another inch. Cutboth of the tubes to that length witha knife or saw.2.Use the scissors to cut out two circlesfrom the manila paper that are thesame size as the diameter of themailing tube. These circle frameswill mount and center the lenses onthe tube. With a knife, cut out circlesthat are slightly smaller than thediameter of the lenses in the centerof the paper frame circle. Glue thelenses to the center of the frame. Theshorter focal length lens will be theeyepiece. Glue that framed lens tothe end of the smaller tube. Glue theother framed lens to the end of thelarger tube.3.Slide the two cardboard tubestogether. You have now assembleda simple refracting telescope. Lookthrough the eyepiece of yourtelescope and focus it on a distantobject. Slide the two cardboardtubes in and out until you have aclear image. What do you observe?4.Use the red and black tape to makestripes on the white posterboard(see illustration on page 55) to useas a chart. Lens with shortestfocal length(eyepiece) Lens with longest focal length(objective lens)Manila frame 56 Converging lenses can be found inmany of the everyday items we see inour homes. How many can you find?Here are a few examples: Paperweights,fish bowls with water in them, bottomsof soda bottles, etc. Junior Home Scientist Diagonal Mirror Newtonian Reflector Telescope Lens Lens Refractor TelescopeMost astronomical telescopes arereflectors. Objective mirrors are easierto make than objective lenses. Largemirrors are structurally easier todesign and less expensive to buildthan large lenses. 58 Optics: An EducatorÕs Guide With Activities in Science and Mathematics EG-2000-10-64-MSFC ProceduresThis microscope will be constructedusing two converging lenses of short focallength suitable fora microscope asdescribed in thetheory section onthe previous page.Two cardboardtelescoping tubesthat fit snugly oneinside the otherwill be the body ofthe microscope.1.To build your microscope, place thelens identified as the eyepiece(ocular) lens on the end of thecardboard tube having the smallestdiameter.2.Take the other lens, the oneidentified as the objective lens, andplace it on the end of the cardboardtube having the largest diameter.3.Slide the two cardboard tubestogether. You have now assembleda simple microscope. View severalitems. Slide the two cardboardtubes in and out until you havea clear image. Observations, Data, and Conclusions1.List the various objects that youexamined through your microscope.Find two additional items to examine.2.Take two of the objects that youexamined through your microscopeand look at them through thelaboratory microscope.3.What differences did you observewhen you looked through themicroscope you made and thelaboratory microscope?4.Which is the better microscope?5.What makes that microscope better? ObjectiveLensEyepiece LensEye LensRetinaOptic NerveEyebrain invertsthe image 60 Optics: An EducatorÕs Guide With Activities in Science and Mathematics EG-2000-10-64-MSFC 46 mm Lens * 28 mm Lens * Manila Folder(Rolled up) 1/2 Inch 1/2 Inch Dowel 4
4
3/4 Inch Base Plate* Lenses may be obtained from school supply store. 62 Optics: An EducatorÕs Guide With Activities in Science and Mathematics EG-2000-10-64-MSFC Procedures1.Stack the two glass flats one on topof the other. Put the flats on theblack construction paper or cardboardprovided. Place the flats under afluorescent light.2.View the flats at an angle so thefluorescent light can be seen in thereflection as shown below. Observethe interference fringes. They willappear as contour lines or concentricrings that are somewhat irregular.3.Press on the glass flats with yourfinger and observe the effect on theinterference fringes. Flourescent LightGlassAirGlassBlackpaper Straight, parallel linesare seen when Uneven, wavy linesare seen when Use of high-quality glass vs.low-quality glass in this experiment Observations, Data, and Conclusions1.Were you able to observe theinterference fringes? What did theylook like?2.What happens when the glass flatsare pressed? 64 Optics: An EducatorÕs Guide With Activities in Science and Mathematics EG-2000-10-64-MSFC Procedures1.Place one Polarizing filter on top ofthe other filter. Look through bothof them toward a light source suchas a fluorescent light or a window.Rotate one of the filters withrespect to the other one until nolight passes through them.2.Place a flat molded plastic objectbetween the two filters and looktoward the light source. Some lightwill now pass through the twoPolarizing filters as illustrated.Observe the pattern of light createdby the transparent piece of plastic;note the corners.3.Using the metal or cardboard frameprovided, cover the frame withoverlapping layers of transparenttape. Use no more than three layersof tape at any overlapping place onthe frame. Place the frame with thetransparent tape between the twoPolarizing filters. Rotate the filtersagain so that the light is blockedout and look at the light source. Polarizer45 Polarize r Material that rotates the plane Unpolarizedsource Observations, Data, and Conclusions1.Why does light not pass through thetwo Polarizing filters turned at 90degrees to each other?2.Why does light pass through themolded transparent plastic?3.What effect do the layers oftransparent tape have on the lightas it passes through them and thePolarizing filters? Experiment with polarized light athome. Find an old pair of Polarizingsunglasses and carefully remove eachlens from the frame. These two lenseswill provide you with two Polarizingfilters to use to examine other materials.Corn syrup in water is another materialthat has the ability to rotate the planeof polarization of light between twoPolarizing filters. For best results, thewater and syrup solution should beput in a clear container with flat sides. 66 Reflection of Light With Two Plane MirrorsDouble Mirrors Placed at a Number of AnglesObservations, Data, and Conclusions1.Computation.2.You will see whole images at 60, 90, and 180 degrees.3.The number of images and the number of mirror frames that are reflected willbe equal.4.The number of images equals 360 degrees divided by the angle indicated on theprotractor.5.The number of observed images and the computed images should be equal, butthe observed images may be one or two less because of the crude equipmentused.Observations, Data, and Conclusions1.There is no exact number of images because the equipment being used is verycrude. The activity is included to encourage the student to observe more carefully.2.The objects appear to be the same size, but they are reflected in parts or pieces.3.In some segments of the kaleidoscope, the images are reversed left to right oreven upside down.Observations, Data, and Conclusions1.The lines are the same as those shown in the illustration at the top of page 17.2.No, the periscope will not function if the mirrors are positioned at different angles. 68 Observations, Data, and Conclusions1.By refraction, a prism can break white light up into its seven major colors.Some of the suggested light sources will appear to be white light to the eye,but a prism will show that some wavelengths are not present.2.The acrylic plastic or plastic prism will refract and break the light into color, butthe quality of the plastic or glass will determine the sharpness of the colors.3.Colors always come out of a prism in the same order. Some colors will be omittedif the light source is not white light.4.The colors blend or shade into each other.5.The bands of color do not always have the same shape or width. The shape orwidth of the color band depends on the type of light source.Observations, Data, and Conclusions1.The colors seem to blend and form other colors. The perception of color isdetermined by light, the source of color; material and its response to color;and the eye of the perceiver of color.2.The colors seen by the student will depend on the design, the kind of pigmentused, and the speed of the movement.3.While spinning, the colors seem to mix and become other colors. The mixingof the colors is a function of the eyes and brain.4.Combine blue and yellow pigments to make green.5.Combine red and yellow pigment to make orange.6.If all colors are equally combined in design, they should make white or gray.The kind of pigment used will affect the colors.7.Most of the time, brown can be made by adding red, yellow, and blue.8.Color one side of the circle and add a few lines or dots on the other halfof the circle. Experiment. 70 4.The smaller water drop magnifies more because of the way it bends or refractslight. The focal length of the small drop is shorter because the curvature of thesurface of the water drop is greater. The shorter the focal length of a lens, thegreater the magnification.5.Bottles with curved edges magnify better.6.The bottom or curved side of a bottle magnifies best.7.The water acts as a lens and refracts or bends light to a focal point.8.Some bottles serve as converging or convex lenses, and they bend or refractthe light to focus it.Observations, Data, and Conclusions1.Answers will vary depending on the lenses provided.2.Answers will vary depending on the lenses provided.3.The lens of the eyepiece of a telescope will have the shorter focal length and thegreater magnification. The object lens will have the longer focal length and lessmagnification.1.Answers will vary depending on the lenses provided.2.With a single lens, the focal image will generally be smaller than the object.The focal image may be the same size as the object, but it will never be larger.3.If you found two distinct images, one will be large and one will be small. Onemay also be reversed. There are two distinct images because the object distanceis different. The object distance is the distance between the object and the lens.The student must consistently use the same object distance whenmeasurements are made.4.Answers will vary depending on the lenses provided. 72 Observations, Data, and Conclusions1.Polarized material allows light to pass through it only in one direction or plane.See the figure on page 64.2.The plastic is transparent and it will allow the light to pass through it, butthe student should notice the bands of color around areas of stress. As theobject was molded into shape, there were areas that were pulled and pushed,and these stress marks were molded into the plastic. The stressed areasinterrupt the light rays entering the plastic and change the plane ordirection of that light.3.The transparent tape changes the plane or direction of polarization. The tapemay also act as a filter and absorb some wavelengths. Layering the tape mayalso reinforce the light waves that are in or out of phase. Two or more lightwaves that exactly match or overlap at the crests and troughs of the waves aresaid to be in phase. When the crests and troughs of two or more waves do notmatch or overlap, the waves are said to be Òout of phase.Ó 74 The point that all light rays from a mirror or lens pass through.frequencyThe number of waves that pass a point in a given unit of time.High-energy wave of high frequency and with a wavelength shorter than an x ray; releasedin a nuclear reaction.The reproduction of an object formed with lenses or mirrors.When two or more light rays overlap exactly at the crest and the trough, they are said to beindex of refractionThe amount that light is refracted when it enters a substance; given as the ratio of speedof light in a vacuum to its speed in a given substance.infrared radiationInvisible radiation with a longer wavelength than red light and next to red light in theelectromagnetic spectrum; used in heat lamps, to detect heat loss from buildings, and todetect certain tumors.interferenceThe addition by crossing wave patterns of a loss of energy in certain areas and reinforcementof energy in other areas.A toy in which reflections from mirrors make patterns. It was invented in 1819by David Brewster.(light amplification by stimulated emission of radiation)A device that produces a highly concentrated, powerful beam of light which is all onefrequency or color and travels only in one direction.law of reflectionAngle of incidence equals the angle of reflection.A curved, transparent object; usually made of glass or clear plastic and used to direct light. 76 reflectionThe light or image you see when light bounces off a surface; bouncing a wave or ray off a surface.reflecting telescopeA telescope in which magnification is produced by a parabolic mirror.refractionBending of a wave or light ray caused by a change in speed as it passes at an angle from onesubstance into another.scatteringThe spreading out of light by intersecting objects, whose size is near the wavelength.sphericalSurface of a lens or mirror that is part of a sphere.subtractive colorOne of the three pure pigment colorsÑmagenta, yellow, cyan; these pigment colors produceblack when mixed.Semitransparent; a material that admits some light.transparentSee-through; light can go through.true imageA true image is the way other people see us. It is the opposite of the image that is seen in amirror.electromagnetic spectrum.virtual imageAn image formed by a mirror or lens that cannot be projected onto a surface.Band of visible colors produced by a prism when white light is passed through it.wavelengthThe total linear length of one wave crest and trough.Invisible electromagnetic radiation of great penetrating power. 78 NASA Educator Resource Center NetworkTo make additional information available to the education community, the NASA EducationDivision has created the NASA Educator Resource Center (ERC) network. ERCÕs contain awealth of information for educators: Publications, reference books, slide sets, audio cassettes,videotapes, telelecture programs, computer programs, lesson plans, and teacher guides withactivities. Because each NASA Field Center has its own areas of expertise, no two ERCÕs areexactly alike. Phone calls are welcome if you are unable to visit the ERC that serves yourgeographic area. A list of the centers and the geographic regions they serve starts on the next page.Regional Educator Resource Centers (RERCÕs) offer more educators access to NASA educationalmaterials. NASA has formed partnerships with universities, museums, and other educationalinstitutions to serve as RERCÕs in many states.Teachers may preview, copy, or receive NASA materials at these sites. A complete list of RERCÕsis available through CORE.ERC and regional ERC locations:http://spacelink.nasa.gov/ercnNASA CORE was established for the national and international distribution of NASA-producededucational materials in audiovisual format. Educators can obtain a catalog and an order form byone of the following methods:¥ NASA CORE Lorain County Joint Vocational School 15181 Route 58 South Oberlin, OH 44074¥ Phone (440) 774Ð1051, Ext. 249 or 293¥ Fax (440) 774Ð2144¥ E-mail: nasaco@lecca.org¥ Home Page: http://core.nasa.gov 80 If you live in:Precollege Officer:Educator Resource Center:FloridaDr. Steve DutczakNASA Kennedy Space Center:GeorgiaChief, Education andNASA KSC Educator Resource CenterPuerto RicoServices BranchMail Code ERCVirgin IslandsNASA Kennedy Space CenterKennedy Space Center, FL 32899Ð0001Mail Code ABÐG1Phone: (407) 867Ð4090Kennedy Space Center, FL 32899Ð0001KentuckyDr. Bill WilliamsNASA Langley Research Center:North CarolinaPrecollege OfficerNASA Langley Educator Resource CenterSouth CarolinaNASA Langley Research CenterVirginia Air and Space CenterVirginiaMail Stop 400Hampton, VA 23669Ð4033West VirginiaHampton, VA 23681Ð0001Phone: (757) 727Ð0900 Ext.757IllinoisMs. Jo Ann CharlestonNASA Lewis Research Center:IndianaChief, Office of Education ProgramsNASA Lewis Educator Resource CenterMichiganNASA Lewis Research CenterMail Stop 8Ð1MinnesotaMail Stop 7Ð421000 Brookpark RoadOhio21000 Brookpark RoadCleveland, OH 44135Ð3191WisconsinCleveland, OH 44135Ð3191Phone: (216) 433Ð2017AlabamaAlicia BeamNASA Marshall Space Flight Center:ArkansasEducation Program SpecialistNASA Marshall EducatorIowaNASA Marshall Space Flight CenterResource CenterLouisianaMail Code CD60One Tranquility Base DriveMissouriHuntsville, AL 35812Ð0001Huntsville, AL 35807Ð7015TennesseePhone: (256) 544Ð8811Phone: (256) 544Ð5812MississippiWanda F. DeMaggioNASA Stennis Space Center:Education Programs ManagerNASA Stennis EducatorNASA Stennis Space CenterResource CenterBldg. 1100 Mail Code AA10Building 1200Stennis Space Center, MS 39529Ð6000Stennis Space Center, MS 39529Ð6000Phone: (228) 688Ð1107Phone: (228) 688Ð3338The Jet PropulsionMr. David M. SeidelNASA Jet Propulsion Laboratory:Laboratory (JPL) servesManager, Educational Affairs OfficeNASA JPL Educator Resource Centerinquiries related toNASA Jet Propulsion LaboratoryMail Code 601Ð107space and planetaryMail Code T1709NASA Jet Propulsion Laboratoryexploration and other4800 Oak Grove Drive4800 Oak Grove DriveJPL activities.Pasadena, CA 91109Ð8099Pasadena, CA 91109Ð8099Phone: (818) 354Ð9313Phone: (818) 354Ð6916 82 NASA Aeronautics CentersNASA Marshall Space Flight Centerhttp://www.msfc.nasa.gov/educationNASA Ames Research Centerhttp://www.arc.nasa.gov/kids.htmlNASA Dryden Flight Research Centerhttp://trc.dfrc.nasa.gov/trc/NASA Langley Research Centerhttp://edu.larc.nasa.govNASA Lewis Research Centerhttp://www.grc.nasa.gov/www/oep 84 Optics: An EducatorÕs Guide With Activities in Science and Mathematics EG-2000-10-64-MSFC Fold along the line and tape closedNational Aeronautics and Space AdministrationEducation DivisionMail Code FEWashington DC 20546-0001 Please PlaceStamp HerePost OfficeWill Not DeliverWithout ProperPostage Optics: An EducatorÕs Guide With Activities in Science and Mathematics X rays are a high-energy called the Advanced X-ray AstrophysicsFacilityÐAXAF) the worldÕs mostfrom space. Astronomers must haveEarthÕs atmosphere absorbs and blocks NASA NASA Projects, MSFC, Optics Observatorythan the Hubble Space Telescope andMSFC. The observatoryÕs telescope wasRay Calibration Facility. vOptics: An EducatorÕs Guide With Activities in Science and Mathematics EG-2000-10-64-MSFC Hubble Space Telescope into orbit onApril 26, 1990. With its vantage pointabove EarthÕs atmosphere Hubble hasJupiter, and storms on Saturn, all with Aft ShroudDouble Roll-out hyperbolic-shaped mirror. The design NASA NASA Projects, MSFC, Optics Telescope viiOptics: An EducatorÕs Guide With Activities in Science and Mathematics EG-2000-10-64-MSFC Space Station Windows NASA NASA Projects, MSFC, Optics activity for its effects on the EarthÕsupper atmosphere. It uses a Wolter Optics: An EducatorÕs Guide With Activities in Science and Mathematics EG-2000-10-64-MSFCviii Classroom ActivitiesActivity 1:Reflection of Light With a Plane (Flat) MirrorActivity 2:Reflection of Light With Two Plane MirrorsActivity 7:Exploring Diffraction With a SpectroscopeActivity 10:Light and Color-Color SpinnersActivity 11:Light and Color-FiltersActivity 12:Light and Color-Hidden MessagesActivity 13:Simple MagnifiersActivity 1:Reflection of Light With a Plane (Flat) MirrorActivity 2:Reflection of Light Withe Two Plane MirrorsActivity 3:Reflection of Light With Two Plane Mirrors-Double SidedActivity 5:Making a PeriscopeActivity 6:Constructing a SpectroscopeActivity 7:Exploring Diffraction with a SpectroscopeActivity 10:Light and Color-Color SpinnersActivity 12:Light and Color-Hidden MessagesActivity 13:Simple MagnifiersActivity 4:Making a KaleidoscopeActivity 5:Making a PeriscopeActivity 8:Diffraction of Light by Very Small AperturesActivity 9:Discovering Color With a PrismActivity 14:Focusing Light With a LensActivity 15:Building a TelescopeActivity 16:Building a MicroscopeActivity 17:Interference FringesActivity 18:Polarization of Light ixOptics: An EducatorÕs Guide With Activities in Science and Mathematics EG-2000-10-64-MSFC Table of ContentsLight, Color, and Their Uses
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2 Optics: An EducatorÕs Guide With Activities in Science and Mathematics Activity/LessonCommunicationProblem SolvingConnectionMeasurement1.Reflection/Plane Mirror2.Reflection/2 Mirrors3.Reflection/Double Mirrors4.Making a Kaleidoscope5.Construction of a Kaleidoscope6.Making a Periscope7.Constructing a Spectroscope8.Exploring Diffraction9.Electromagnetic Spectrum10Diffraction of Light11.Discovering Color/Prism12.Fabrication of a Prism13.Color Spinners14.Filters15.Hidden Messages16.Simple Magnifiers17.Focusing Light With a Lens18.Building a Telescope19.Building a Microscope20.Construction of a Micoscope21.Interference Fringes22.Polarization of Light 3 Optics: An EducatorÕs Guide With Activities in Science and Mathematics Introduction to Light and ColorIntroduction to LightLight is a form of radiant energyor energy that travels in waves. SinceGreek times, scientists have debatedthe nature of light. Physicists nowrecognize that light sometimesbehaves like waves and, at other times,like particles. When moving from placeto place, light acts like a system ofwaves. In empty space, light has afixed speed and the wavelength can bemeasured. In the past 300 years,scientists have improved the way theymeasure the speed of light, and theyhave determined that it travels atnearly 299,792 kilometers, or 186,281miles, per second.When we talk about light, we usuallymean any radiation that we can see.These wavelengths range from about16/1,000,000 of an inchto 32/1,000,000 of an inch. There areother kinds of radiation such asultraviolet light and infrared light, buttheir wavelengths are shorteror longer than the visible lightwavelengths.When light hits some form ofmatter, it behaves in different ways.When it strikes an opaque object, itmakes a shadow, but light does bendaround obstacles. The bending of lightaround edges or around small slits iscalled diffraction and makes patternsof bands or fringes.All light can be traced to certainenergy sources, like the Sun, anelectric bulb, or a match, but mostof what hits the eye is reflected light.When light strikes some materials,it is bounced off or reflected. If thematerial is not opaque, the light goesthrough it at a slower speed, and itis bent or refracted. Some light isabsorbed into the material andchanged into other forms of energy,usually heat energy. The light wavesmake the electrons in the materialsvibrate and this kinetic energy ormovement energy makes heat. Frictionof the moving electrons makes heat. 4 Optics: An EducatorÕs Guide With Activities in Science and Mathematics Introduction to ColorColor is a part of the electro-magnetic spectrum and has alwaysexisted, but the first explanation ofcolor was provided by Sir IsaacNewton in 1666.Newton passed a narrow beam ofsunlight through a prism located ina dark room. Of course all the visiblespectrum (red, orange, yellow, green,blue, indigo, and violet) was displayedon the white screen. People alreadyknew that light passed through aprism would show a rainbow or visiblespectrum, but NewtonÕs experimentsshowed that different colors are bentthrough different angles. Newton alsothought all colors can be found inwhite light, so he passed the lightthrough a second prism. All the visiblecolors changed back to white light.Light is the only source of color.The color of an object is seen becausethe object merely reflects, absorbs, andtransmits one or more colors thatmake up light. The endless variety ofcolor is caused by the interrelationshipof three elements: Light, the source ofcolor; the material and its response tocolor; and the eye, the perceiver of color.Colors made by combining blue,yellow, and red light are calledadditive; and they are formed byadding varying degrees of intensityand amounts of these three colors.These primary colors of light arecalled cyan (blue-green), yellow, andmagenta (blue-red).Pigment color found in paint, dyes,or ink is formed by pigment moleculespresent in flowers, trees, and animals.The color is made by absorbing, orsubtracting, certain parts of thespectrum and reflecting or transmittingthe parts that remain. Each pigmentmolecule seems to have its owndistinct characteristic way of reflecting,absorbing, or transmitting certainwavelengths. Natural and manmadecolors all follow the same natural laws. 9 Optics: An EducatorÕs Guide With Activities in Science and Mathematics Object(3)(1)c(2)f Image ir OpticalAxis Introduction to LensesA simple lens is a piece of glass orplastic having two polished surfacesthat each form part of a sphere or ball.One of the surfaces must be curved;the other surface may be curved orflat. An example of a simple lens wouldbe obtained if a piece of a glass ballwere sliced off as shown in thefollowing illustration.The piece of the ball sliced offwould be a lens with a spherical sideand a flat side. Lenses can be madein a variety of shapes for variousapplications. Some examples of lensshapes are illustrated here. Glass BallLens (1)(2)(3)(4)(5) A lens thicker in the center thanat the edge is called a converging orpositive lens. A lens thinner at thecenter than at the edge is calleda diverging or negative lens. In theillustration shown, lenses 1, 2, and 3are converging or positive lenses.Lenses 4 and 5 are diverging ornegative lenses. 11 Optics: An EducatorÕs Guide With Activities in Science and Mathematics When the object lies between thelens and the focal point, a virtual,upright, and enlarged image is obtained,as seen in the illustration below.Three rays are included in theillustration. Following are descriptionsof these rays. A ray (1) leaving theobject parallel to the optical axis willbend at the lens and go through thefocal point (f). A ray (2) leaving theobject going through the center ofthe lens will be undeviated. A ray(3) leaving the object as if it camefrom the front focal point of the lenswill bend at the lens and travel in aline parallel to the optical axis. ObjectVirtualImageOptical Axisf(3)(1)(2)f After passing through the lens, thethree rays described above will appearto come from an enlarged and uprightimage. Any other ray leaving the tip ofthe object will appear to come fromthe tip of the image after passingthrough the lens. The three rays usedin the illustration below were chosenbecause their paths are always known.Two rays are actually enough to locatethe image, while the third ray is usedfor an additional check of the locationof the image. 12 Optics: An EducatorÕs Guide With Activities in Science and Mathematics 14
\b\t\n\t\f\rOptics: An EducatorÕs Guide With Activities in Science and Mathematics EG-2000-10-64-MSFC Procedures 1. Stand the mirror at 90 degrees tothe surface of the table.2. Stand the two wooden blocks onthe ends. Position them parallel toeach side of the mirror and 10inches from the face of the mirror. Start Here Reflection in Mirror 12"
12" Mirror TileCardboardWooden Blocks Tracing Pattern 3. Place the cardboard horizontallyacross the top of the two woodenblocks. Place a paper tracingpattern on the flat surface betweenthe two blocks of wood.4. Place your finger or pencil at thestarting point on the pattern.5. Look only in the mirror and trace thestar pattern found on page 5. Nowtrace the swirl pattern also on page 5. 15 Tracing Pattern #1 Start Here* Tracing Pattern #2 Start 20
\b\t\n\t\f\rOptics: An EducatorÕs Guide With Activities in Science and Mathematics EG-2000-10-64-MSFC Procedures 1.Place the protractor on a table andstand the two mirrors on top of itat a 90-degree angle. The mirrorsshould be placed so that you canreadily measure the angle as youopen and close the mirrors.2.Place the mirrors at a 90-degreeangle. How many mirrors do yousee? How many complete images doyou see? How many parts of imagesdo you see? Record your observationsin the chart on page 21.3.Change the mirrors to a 10-degreeangle and count the whole imagesand the parts of images that yousee. Repeat step 2.4.Continue to change the degrees ofthe angle from 0 through 180degrees and repeat step 2.HINT: When you look into the mirrors,place your face between the twomirrors or as close to the edges aspossible. Keep your face perpendicularto the space or hinge between the twomirrors. ProtractorTape 1.Make your observations as youcomplete the table on the followingpage. (Refer to question No. 4 below.)2.At what degrees or angles do youseem to see whole images and nopartial images?3.How does the number of degreesseem to be related to the numberof mirrors that you count?4.Using the following formula,compute each angle measured andcompare your answers to what yousee in the mirror. Because you areusing simple materials, yourobservations may differ slightlywith the computations.Number of images observed inmirror equals 360 degrees dividedby angle indicated on theprotractor.Example: 360 = 4 imagesPerform the math computationsand complete the table in questionNo. 1 above.5.Are the number of observed imagesand the computed math answers thesame? Why or why not? Observations, Data, and Conclusions 21 Optics: An EducatorÕs Guide With Activities in Science and Mathematics EG-2000-10-64-MSFC AngleNumber ofMirrorsObservedNumber ofImagesObservedComputations 10û20û30û40û50û60û70û80û90û100û110û120û130û140û150û160û170û180û\n\t\r 22
\b\t\n\t\f\rOptics: An EducatorÕs Guide With Activities in Science and Mathematics EG-2000-10-64-MSFCMath Computations: 23 Optics: An EducatorÕs Guide With Activities in Science and Mathematics EG-2000-10-64-MSFCMaking a Kaleidoscope Level: Grades (9Ð12)Activity: 4 AB Objective Science and Mathematics Standards Theory Materials The student will experiment withmultiple reflections in mirrors.Science as InquiryPhysical ScienceProblem SolvingCommunicationConnectionComputation/EstimationMeasurementWhen three rectangular mirrorsthat are the same size are arrangedin an equilateral triangle (See Glossary,page 73), rays of light from an objectform multiple images due to reflectionsfrom the mirrors. The equilateral triangleformed by the mirrors has three equalangles of 60 degrees, and the sides haveequal lengths.¥ 3 flat rectangular mirrors of equal size¥ rubber bands¥ Transparent tape¥ small items to put in thekaleidoscope (glitter, confetti, ect.)¥ a piece of white cardboard¥ resealable bag 24
\b\t\n\t\f\rOptics: An EducatorÕs Guide With Activities in Science and Mathematics EG-2000-10-64-MSFC Procedures 1. Place the three mirrors together asshown, using the long side of eachmirror. Put a few pieces of tape onthe backs of the mirrors to holdthem together.2. Put two of the rubber bands aroundthem to hold them securely together.3. Use this simple kaleidoscope to dothe following activities.A.Hold the kaleidoscope in your handand look through it at objectsaround the room.B.Hold the kaleidoscope above thewhite cardboard and look downinside it. Put some object such as acoin, or the small pieces of coloredpaper in the resealable bag (keepthem in the bag) on the whitecardboard inside the kaleidoscope.Observe the images reflected in themirrors. MirrorsSmall Objects Rubber Observations, Data, and Conclusions 1.How many images did you see?2.Did the images appear to be thesame size as the object?3.How were the objects oriented withrespect to the reflected images? 25 Construction of a Large(Adult Supervision Is Requiredat All Times) Junior Home Scientist Project Materials ¥ 1 piece of PVC pipe 10 centimeters(about 4 inches) in diameter andabout 16 inches long¥ 12-inch mirror tile¥ hack saw with fine blade¥ 1 glass cutter¥ sandpaper¥ flat black spray paint¥ white glue¥ epoxy glue¥ cardboard¥ foam rubber used for packing andshipping¥ scissors or utility knife¥ thick leather gloves¥ red, blue, or yellow paint (optional)¥ contact paper (optional) Procedures 1.Buy or cut to size the 16-inchlength of PVC pipe. Sand the edgesand corners of the pipe until theyare smooth.2.Use the flat black paint and spraythe inside of the pipe. Leave thepaint to dry overnight. Later, paintthe outside of the pipe any color ordesign that you desire. Contactpaper could also be used.3.While wearing leather gloves, cutthe 12-inch square mirror tile into3-inch strips. Sand the edges of themirrors.4.Position the three strips of glassclose to one end of the PVC pipe.Place the mirrors to form three60-degree angles.5.Use the epoxy to glue the mirrorsinside the pipe. Pack foam behindeach mirror to provide stability.6.Cut a circular piece of cardboard tofit the inside diameter of the pipe.Cut a 1-inch hole in the middle ofthe cardboard. \n\t\r 26
\b\t\n\t\f\rOptics: An EducatorÕs Guide With Activities in Science and Mathematics EG-2000-10-64-MSFC PVC pipe 4 inches in diameter and Cardboard endpieceFoam rubberThree mirror tiles anglesCardboard eyepiecePVC pipe 4 inches Cardboard endpieceFoam rubberTwo mirror tiles glued anglesCardboard endpiece 7.Position this circular cardboardpiece into the end of the PVC pipeand glue it with white glue to formthe eye piece of the kaleidoscope.8.Now cut another circular cardboardpiece to fit the opposite end of thepipe. In the center of the cardboardcut a triangle with three 60-degreeangles.9. Match this triangular opening withthe opening formed by the threemirrors and use the white glue toglue the cardboard into place.It is also possible to make akaleidoscope using two mirrorspositioned at a 20-degree angle. Youmay fill in the third side with a pieceof mirror tile. Experiment withvarious angles of the mirrors andlocations of the eyepiece holes.Kaleidoscopes made with smallerangles are more interesting. 27 Optics: An EducatorÕs Guide With Activities in Science and Mathematics EG-2000-10-64-MSFCMaking a Periscope AB Objective Science and Mathematics Standards Theory Materials The student will experiment with asimple periscope to see how it reflects light.Science as InquiryPhysical ScienceProblem SolvingCommunicationConnectionComputation/EstimationMeasurementA periscope is an optical instrumentthat uses a system of prisms, lenses, ormirrors to reflect images through atube. Light from a distant object strikesthe top mirror and is then reflected atan angle of 90 degrees down theperiscope tube. At the bottom of theperiscope, the light strikes anothermirror and is then reflected into theviewerÕs eye. This simple periscope usesonly flat mirrors as compared to theperiscopes used on submarines, whichare usually a complex optical systemusing both lenses and mirrors.¥ 2 flat mirrors¥ a cardboard tube with openings oneach end¥ wooden supports¥ tape Level: Grades (5Ð8), (9-12)Activity: 5\n\t\r 28
\b\t\n\t\f\rOptics: An EducatorÕs Guide With Activities in Science and Mathematics EG-2000-10-64-MSFC Procedures Insert both flat mirrors into theperiscope viewing tube as shown. Themirrors must be facing each other.When the mirrors are insertedcorrectly each mirror will be restingon the wooden supports. As eachmirror is inserted, place a small pieceof Scotch tape over the mirror slots onthe outside of the viewing tube. Holdthe periscope so the mirrors are restingon the wooden supports, then lookthrough it.NOTE: The mirrors will fall out if youturn your periscope upside down. Object 0" 2"3"2"3" Cut-out squareof cardboard Observations, Data, and Conclusions Junior Home Scientist 1.Draw a diagram of the path a rayof light follows as it travels from anobject, through the periscope, andinto your eye.2.Do you think the periscope wouldwork if the mirrors were at someangle other than 45 degrees?A periscope can easily be madefrom materials that you can find athome. The drawing above gives you anexample to use. Mirrors of any sizewill do, as long as they are flat. 29 Constructing a Spectroscope Level: Grades (5Ð8)Activity: 6 AB Objective Science and Mathematics Standards Theory Materials With adult supervision the studentwill construct a simple spectroscope.Science as InquiryPhysical ScienceProblem SolvingCommunicationConnectionComputation/EstimationMeasurementAll elements or pure substances, suchas gold, silver, neon, or hydrogen, give offa set of wavelengths of light when theyare heated. Scientists can study the lightgiven off by stars and other objects inspace or heated substances here onEarth and identify the kinds of elementsthat are present. In fact, the elementhelium, which is a very light gas, wasdiscovered by studying the spectral linesof the Sun. Later, helium was found hereon Earth. Scientists who study light usevery complicated spectroscopes toobserve and measure wavelengths givenoff by light sources.¥ 1 cardboard box with lid¥ sharp knife or blade¥ 1 double-edged razor blade¥ scissors¥ black marker¥ tape¥ 1 manila file folder¥ commercially purchased diffractiongrating (plastic material with 13,440grooves per square inch). (See List ofCatalogs, page 83.) 30
\b\t\n\t\f\rOptics: An EducatorÕs Guide With Activities in Science and Mathematics EG-2000-10-64-MSFC Procedures 1.Make or adapt a box that is about 10inches long, 6 inches wide, and 2inches deep. The box must have atight lid.2.Use a black marker and color theinside of the box and lid.3.Choose one end of the box andmeasure 1/4 inch from the corner.WITH ADULT HELP ORSUPERVISION, cut out a 1-inchsquare hole.4.Next cut a piece of diffractiongrating 1Ð1/2 inches square.5.Cut a frame of manila paper for thediffraction grating. The sidemeasurements should be 1Ð1/2inches square, and insidemeasurements for the hole in theframe should be 1 inch square.6.Frame the diffraction grating andtape it inside the box to cover the1-inch square hole cut in step No. 3,with lines of the diffractiongrating vertical.7.Directly opposite the diffractiongrating on the other end of the box,measure and mark 1/2 inch from thecorner of the box and 1/4 inch fromthe bottom. WITH ADULT HELP ORSUPERVISION, cut a hole 1-inchhigh and 1/2-inch wide.8.Cut a rectangle of manila paper 1Ð1/2inches by 2 inches. In the center ofthe manila rectangle, cut a smallrectangular hole 3/4-inch high and1/4-inch wide.9.WITH ADULT SUPERVISION,break the razor blade into twopieces along the long hole in theblade. Pl a ce t h e s h a rp ed g es o f t h e b l a d e t og e t h e r t o f o rm a l o n g n a rr o w s l i 10.Mount the razor blade slit so thatthe long slit is parallel to the linesof the diffraction grating.11.WITH ADULT SUPERVISION,center the slit in the double-edgerazor blade over the opening in thelarge manila rectangular frame.Tape pieces of the blade in place.12.Tape the framed razor blade to theoutside of the box on the endopposite from the diffraction grating.13.Place the lid securely on the box.Find a light source. Aim the razorblade at the light and look throughthe diffraction grating.14.Observe the emission spectrumemitted by the light source. Diffraction GratingManila Paper1 1/2"
1 1/2"Hole1"
1"Lid Razor Blade Manila Paper1 1/2"
2" Hole 1"
1 1/2" 31 With a Spectroscope Level: Grades (KÐ4), (5-8)Activity: 7 AB Objective Science and Mathematics Standards Theory Materials The student will be able to seewhat happens to light when it passesthrough a spectroscope.Science as InquiryPhysical ScienceProblem SolvingCommunicationConnectionComputation/EstimationMeasurement¥ spectroscope (one spectroscope forfour students)¥ light sources (sunlight,incandescent, fluorescent, cadmium,sodium, neon, mercury, helium, etc.)(See List of Catalogs, page 83.)¥ diffraction grating¥ compact discA spectroscope is a device that can beused to look at the group of wavelengthsof light given off by an element. Allelements give off a limited number ofwavelengths when they are heated andchanged into gas. Each element alwaysgives off the same group of wavelengths.This group is called the emissionspectrum of the element.In the visible wavelengths of theelectromagnetic spectrum, red, with thelongest wavelength, is diffracted most; andviolet, with the shortest wavelength, isdiffracted least. Because each color isdiffracted a different amount, each colorbends at a different angle. The result isa separation of white light into the sevenmajor colors of the spectrum or rainbow.A good way to remember these colors inorder is the name Roy G. Biv. Each letterbegins the name of a color: red, orange,yellow, green, blue, indigo, and violet.(Reference Electromagnetic Spectrumpage 34.) 32 (Students should color these boxes with their crayons.) ROGBIVRedOrangeGreenBlueIndigoViolet YYellow Procedures Use a spectroscope and look atdifferent kinds of light. View bulbswith different gases inside. Observations, Data, and Conclusions 1.Observe each source of light. Explainwhat you see.2.Observe the colors. Start with thefirst color on the left and list themin the table in the order that yousee them.3.When you look at the different lightsources through the spectroscope,observe the stripes of color. Do theyfade or blend into each other?Describe the bands of color.4.Does each light source produce thesame group of colors or spectrum?5.Each group of colors for each differentlight source is called the emissionspectrum for that source. How are thespectra or groups of colors alike?Different?6.Why are the groups of color for eachlight source different? ColorsLight Source 33 Optics: An EducatorÕs Guide With Activities in Science and Mathematics EG-2000-10-64-MSFC ActivitiesAdditional Activities White light can be separated intoall seven major colors of the completespectrum or rainbow by using adiffraction grating or a prism. Thediffraction grating separates light intocolors as the light passes through themany fine slits of the grating. This is atransmission grating. There are alsoreflection gratings. A reflection gratingis a shiny surface having many finegrooves. A compact disc makes a goodreflection grating.The prism separates light intocolors because each color passesthrough the prism at a different speedand angle. The angles of reflection ofthe light, upon entering and leavingthe prism, vary with the wavelength orcolor of the light. LightDiffracted Diffraction Grating RedVioletWhite LightPrism \f\t\r 39 Optics: An EducatorÕs Guide With Activities in Science and Mathematics EG-2000-10-64-MSFC ActivitiesAdditional Activities Junior Home Scientist Repeat the previous activities witha high quality prism (highly dispersive).What differences do you observebetween the acrylic plastic or plasticprism and the prism made out ofoptical quality glass?You can make a prism at home byplacing a flat mirror in a shallow panof water. Put the pan of water in awindow where the Sun can shine intothe water. (See the figure below.) Thesunlight reflected from the mirror canbe seen as a rainbow of colorsreflected on a wall. SunlightWindowMirrorPan of Water \b\t\n\t\f\t\r 46 1.Using at least 3 different magicmarker colors, draw a design. Thinkin terms of space and astronomydesigns.2.Use magic markers to draw moredesigns, be sure to include at leastone hidden message in yourdesigns. Can you hide three or moremessages in one design?(Students should use a space orastronomy word as their hiddenmessage and then draw designsover it.)3.View the design through severalfilters. Procedures Observations, Data, and Conclusions 1.When you viewed the designswithout a filter, what did you see?2.What did you see when you looked atyour design with each colored filter?3.What did you see when you usedtwo different filters together?4.Why did you see different thingswith each different filter?5.If possible, exchange designs withanother person and read theirsecret message. 47 Optics: An EducatorÕs Guide With Activities in Science and Mathematics EG-2000-10-64-MSFCSimple Magnifiers Simple double-convex lenses can makegood magnifiers. Some transparent bottlesand jars bend light and magnify print.They may also reverse the print. Water ina jar or a drop of water can also serve asa magnifier.¥ photographic slide frame or thinpiece of cardboard with a 1-inchsquare hole¥ transparent tape¥ small transparent sauce orcondiment bottles¥ jars of different shapes¥ water¥ old magazine or newspaper AB Objective Science and Mathematics Standards Science and Mathematics Standards Materials The student will experiment withmagnifiers.Science as InquiryPhysical ScienceProblem SolvingCommunicationConnectionComputation/EstimationMeasurement 48
\b\t\n\t\f\rOptics: An EducatorÕs Guide With Activities in Science and Mathematics EG-2000-10-64-MSFC Procedures Observations, Data, and Conclusions 1.Place a piece of transparent tapeacross the opening of the slide orcardboard. Wet one finger and placeone small drop of water onto the tape.2.Position the water drop above thenewspaper or numbers. Can youread the letters or numbers?3.Continue to experiment. Use a bigdrop of water. Use a tiny drop ofwater. Hold the drop very close tothe letters and words. Move thedrop slowly away from the words.Keep experimenting.4.Now place the edges of the bottlesclose to the words. Do all of thebottles magnify? Do some of themmagnify? Do they magnify better ifyou put water in them? Experimentwith bottles of all shapes. Do somejars of water reverse letters?Water Drop Magnifier1.What did you see when you lookedthrough the drop of water?2.Could you read the letters? Did theletters and numbers appear larger?3.How did you focus the water dropmagnifier?4.Which water drop magnified more,the large drop or the small drop?Why? Hint: How does the size ofthe water drop effect the way lightis bent or refracted?5.What shape bottle or jar magnifiesbest?6.What parts of bottles magnify best?7.Do these bottles or jars magnifybetter with water in them?8.Why do bottles magnify objects? Cardboard orSlide Frame Transparent 49 Optics: An EducatorÕs Guide With Activities in Science and Mathematics EG-2000-10-64-MSFC When light from a source that is aninfinite distance away passes through aconverging lens, the light will come to a AB Objective Science and Mathematics Standards Theory Materials The student will experiment witha converging lens that has a focal pointwhich can be easily measured. Using alens, the student will observe the imageof an object through a lens and willdetermine the magnification of that lens.Science as InquiryPhysical ScienceProblem SolvingCommunicationConnectionComputation/EstimationMeasurementfocus at the focal point of the lens. Sinceit is inconvenient to get infinite distancesin the classroom, the following lensequation is used to compute the focallength of a lens:The measured distance of the object,, from the lens, and the measureddistance of the image, D, are usedto compute the focal length, , of aconverging lens. A more convenientform of this equation is¥ 2 converging lenses¥ a white cardboard imaging screen¥ a meter stick or metric ruler¥ a 12-inch ruler¥ a light source (flashlight)¥ an object such as an arrow made oftape on the flashlight lens cover
\r\f\t\r 53 Optics: An EducatorÕs Guide With Activities in Science and Mathematics EG-2000-10-64-MSFC Building a Telescope Theory AB Objective Science and Mathematics Standards Materials In a telescope, the lens held nextto your eye is called the eyepiece andis usually a short focal length lens ora combination of lenses. The lens atthe other end of the telescope iscalled the objective lens. Light froma distant object is focused by theobjective lens to form an image infront of the eyepiece. The eyepieceacts as a magnifier and enlarges thatimage. The magnification of thetelescope can be found by dividingthe focal length of the objective bythe focal length of the eyepiece.¥ 2 converging lenses (convex lenses)¥ telescoping tubes (mailing tubes)¥ manila file folder¥ scissors¥ knife or saw¥ glue¥ 1 white poster board¥ red and black tapeThe student will construct a simplerefracting telescope and calculate themagnification.Science as InquiryPhysical ScienceProblem SolvingCommunicationConnectionComputation/EstimationMeasurement
\r\f\t\r 54
\b\t\n\t\f\rOptics: An EducatorÕs Guide With Activities in Science and Mathematics EG-2000-10-64-MSFC Procedures This telescope will be constructedusing the same lenses that were usedin the experiment named, ÒFocusingLight With a Lens,Ó page 49.1.The mailing tubes will be the bodyof the telescope with the smallerone sliding inside the larger one.The length of the assembledtelescope will be a little longer thanthe sum of the focal lengths of thetwo lenses. Add the value of thefocal lengths of the short and longlens together. Divide that length bytwo and then add another inch. Cutboth of the tubes to that length witha knife or saw.2.Use the scissors to cut out two circlesfrom the manila paper that are thesame size as the diameter of themailing tube. These circle frameswill mount and center the lenses onthe tube. With a knife, cut out circlesthat are slightly smaller than thediameter of the lenses in the centerof the paper frame circle. Glue thelenses to the center of the frame. Theshorter focal length lens will be theeyepiece. Glue that framed lens tothe end of the smaller tube. Glue theother framed lens to the end of thelarger tube.3.Slide the two cardboard tubestogether. You have now assembleda simple refracting telescope. Lookthrough the eyepiece of yourtelescope and focus it on a distantobject. Slide the two cardboardtubes in and out until you have aclear image. What do you observe?4.Use the red and black tape to makestripes on the white posterboard(see illustration on page 55) to useas a chart. Largermailing tube Lens with shortestfocal length(eyepiece) Manila frame Lens with longest focal length(objective lens)Manila frame 56 Converging lenses can be found inmany of the everyday items we see inour homes. How many can you find?Here are a few examples: Paperweights,fish bowls with water in them, bottomsof soda bottles, etc. Junior Home Scientist Diagonal Mirror EyepieceParabolic Mirror Newtonian Reflector Telescope Lens Lens EyepieceObjective Lens Refractor TelescopeMost astronomical telescopes arereflectors. Objective mirrors are easierto make than objective lenses. Largemirrors are structurally easier todesign and less expensive to buildthan large lenses. 57 Building a Microscope Level: Grades (9Ð12)Activity: 16 AB Objective Science and Mathematics Standards Theory Materials The student will construct a simplelow-power microscope from twoconverging lenses. See pages 59Ð62.The student will be able to see howa microscope works.Science as InquiryPhysical ScienceProblem SolvingCommunicationConnectionComputation/EstimationMeasurementIn a microscope, the lens, placednext to the object to be magnified, iscalled the objective lens, while thelens held next to the eye is called theeyepiece. The eyepiece should have afocal length of about 25 millimeters,while the objective should have a focallength of 25 millimeters or less to besuitable for building a microscope.The distance to the enlarged imageformed by the objective lens is 160millimeters. The enlarged imageformed by the objective lens ismagnified by the eyepiece.¥ 2 converging lenses (convex lenses)¥ telescoping tubes (mailing tubes)¥ a selection of materials to view withthe microscope¥ a laboratory microscope 58
\b\t\n\t\f\rOptics: An EducatorÕs Guide With Activities in Science and Mathematics EG-2000-10-64-MSFC Procedures This microscope will be constructedusing two converging lenses of short focallength suitable fora microscope asdescribed in thetheory section onthe previous page.Two cardboardtelescoping tubesthat fit snugly oneinside the otherwill be the body ofthe microscope.1.To build your microscope, place thelens identified as the eyepiece(ocular) lens on the end of thecardboard tube having the smallestdiameter.2.Take the other lens, the oneidentified as the objective lens, andplace it on the end of the cardboardtube having the largest diameter.3.Slide the two cardboard tubestogether. You have now assembleda simple microscope. View severalitems. Slide the two cardboardtubes in and out until you havea clear image. Observations, Data, and Conclusions 1.List the various objects that youexamined through your microscope.Find two additional items to examine.2.Take two of the objects that youexamined through your microscopeand look at them through thelaboratory microscope.3.What differences did you observewhen you looked through themicroscope you made and thelaboratory microscope?4.Which is the better microscope?5.What makes that microscope better? ObjectObjectiveLensEyepiece LensEye LensRetinaOptic NerveEyebrain invertsthe image 60
\b\t\n\t\f\rOptics: An EducatorÕs Guide With Activities in Science and Mathematics EG-2000-10-64-MSFC 46 mm Lens * 28 mm Lens * Manila Folder(Rolled up) 1/2 Inch 1/2 Inch Dowel 4
4
3/4 Inch Base Plate* Lenses may be obtained from school supply store. 61 Interference Fringes Level: Grades (9Ð12)Activity: 17 AB Objective Science and Mathematics Standards Theory Materials The student will observeinterference fringes formed by a layerof air between two pieces of glass.Science as InquiryPhysical ScienceProblem SolvingCommunicationConnectionComputation/EstimationMeasurementWhen light of a single color (orwavelength) passes through the layerof air between two flat pieces of glass,part of the light is reflected by theglass-to-air boundary and part isreflected from the air-to-glass boundary.If the difference in the paths of thetwo rays is equal to a multiple ofwhole wavelengths, the light amplitudewill add to form a bright band. Thedark bands are formed by rays thatcancel each other. A good source oflight that has some single colors is afluorescent light. The light looks whiteto your eyes even though it contains abright green component caused by themercury vapor in the tube. This iscalled the mercury green line and hasa wavelength of 5,461 angstroms, whichis 0.5461 millimeters (0.5461 EÐ6 meters).See the illustration on page 62.¥ 2 glass flats (glass microscope slides)(see List of Catalogs, page 83.)¥ sheet of black construction paper¥ a light source such as an overheadfluorescent light¥ 1 set high-quality flats (optional)(see List of Catalogs, page 83.) 80 If you live in:Precollege Officer:Educator Resource Center:FloridaDr. Steve DutczakNASA Kennedy Space Center:GeorgiaChief, Education andNASA KSC Educator Resource CenterPuerto RicoServices BranchMail Code ERCVirgin IslandsNASA Kennedy Space CenterKennedy Space Center, FL 32899Ð0001Mail Code ABÐG1Phone: (407) 867Ð4090Kennedy Space Center, FL 32899Ð0001KentuckyDr. Bill WilliamsNASA Langley Research Center:North CarolinaPrecollege OfficerNASA Langley Educator Resource CenterSouth CarolinaNASA Langley Research CenterVirginia Air and Space CenterVirginiaMail Stop 400Hampton, VA 23669Ð4033West VirginiaHampton, VA 23681Ð0001Phone: (757) 727Ð0900 Ext.757IllinoisMs. Jo Ann CharlestonNASA Lewis Research Center:IndianaChief, Office of Education ProgramsNASA Lewis Educator Resource CenterMichiganNASA Lewis Research CenterMail Stop 8Ð1MinnesotaMail Stop 7Ð421000 Brookpark RoadOhio21000 Brookpark RoadCleveland, OH 44135Ð3191WisconsinCleveland, OH 44135Ð3191Phone: (216) 433Ð2017AlabamaAlicia BeamNASA Marshall Space Flight Center:ArkansasEducation Program SpecialistNASA Marshall EducatorIowaNASA Marshall Space Flight CenterResource CenterLouisianaMail Code CD60One Tranquility Base DriveMissouriHuntsville, AL 35812Ð0001Huntsville, AL 35807Ð7015TennesseePhone: (256) 544Ð8811Phone: (256) 544Ð5812MississippiWanda F. DeMaggioNASA Stennis Space Center:Education Programs ManagerNASA Stennis EducatorNASA Stennis Space CenterResource CenterBldg. 1100 Mail Code AA10Building 1200Stennis Space Center, MS 39529Ð6000Stennis Space Center, MS 39529Ð6000Phone: (228) 688Ð1107Phone: (228) 688Ð3338The Jet PropulsionMr. David M. SeidelNASA Jet Propulsion Laboratory:Laboratory (JPL) servesManager, Educational Affairs OfficeNASA JPL Educator Resource Centerinquiries related toNASA Jet Propulsion LaboratoryMail Code 601Ð107space and planetaryMail Code T1709NASA Jet Propulsion Laboratoryexploration and other4800 Oak Grove Drive4800 Oak Grove DriveJPL activities.Pasadena, CA 91109Ð8099Pasadena, CA 91109Ð8099Phone: (818) 354Ð9313Phone: (818) 354Ð6916 81 On-Line Resources for EducatorsNASAÕs Education Home Page serves as a cyber-gateway to information regarding educationalprograms and services offered by NASA for educators and students across the United States. Thishigh-level directory of information provides specific details and points of contact for all of NASAÕseducational efforts and Fields Center offices.Educators and students utilizing this site will have access to a comprehensive overview of NASAÕseducational programs and services, along with a searchable program inventory that has catalogedNASAÕs educational programs.NASA Education Home Page:http://education.nasa.govNASA Spacelink is one of NASAÕs electronic resources specifically developed for the educationalcommunity. Spacelink is a Òvirtual libraryÓ in which local files and hundreds of NASA WorldWide Web links are arranged in a manner familiar to educators. Using the Spacelink searchengine, educators can search this virtual library to find information regardless of its locationwithin NASA. Special events, missions, and intriguing NASA web sites are featured in SpacelinkÕsÒHot TopicsÓ and ÒCool PicksÓ areas.Spacelink may be accessed at: http://spacelink.nasa.govNASA Spacelink is the official home to electronic versions of NASAÕs Educational Products. NASAeducator guides, educational briefs, lithographs, and other materials are cross-referenced throughoutSpacelink with related topics and events. A complete listing of NASA Educational Products can befound at the following address:http://spacelink.nasa.gov/productsÒEducator FocusÓ is comprised of a series of Spacelink articles, which offers helpful informationrelated to better understanding and using NASA educational products and services. Visit ÒEducatorFocusÓ at the following address:http://spacelink.nasa.gov/focusJoin the NASA Spacelink EXPRESS mailing list to receive announcements of new NASAmaterials and opportunities for educators. Our goal is to inform you as quickly as possible whennew NASA educational publications become available on Spacelink:http://spacelink.nasa.gov/express 82 NASA Aeronautics CentersNASA Marshall Space Flight Centerhttp://www.msfc.nasa.gov/educationNASA Ames Research Centerhttp://www.arc.nasa.gov/kids.htmlNASA Dryden Flight Research Centerhttp://trc.dfrc.nasa.gov/trc/NASA Langley Research Centerhttp://edu.larc.nasa.govNASA Lewis Research Centerhttp://www.grc.nasa.gov/www/oep 83 Carolina Biological Supply Co.2700 York RoadBurlington, NC 27215Central Scientific Co. (CENCO)11222 Melrose AvenueFranklin Park, IL 60131Delta Education, Inc.P.O. Box 950Hudson, NH 03051Dick Blick Art MaterialsP.O. Box 1267Galesburg, IL 61401Edmund Scientific Company*(Specialty Optics)101 E. Gloucester PikeBarrington, NJ 08007Ð1380Flinn Scientific, Inc.P.O. Box 219131 Flinn StreetBatavia, IL 60510Ð9906Fisher Scientific Co.Educational Materials Division4901 W. LeMoyne StreetFrey Scientific Co.P.O. Box 8101905 Hickory LaneMansfield, OH 44901Ð81011Ð800Ð25ÐFREYHubbardP.O. Box 104Northbrook, IL 60065901 Janesville AvenueFort Atkinson, WI 53538Oriental Trading Company, Inc.P.O. Box 3407Omaha, NE 68103Science Kit and Boreal Labs777 E. Park DriveTonawanda, NY 14150SciencewareGrau-Hall Scientific6501 Elvas AvenueSacramento, CA 95819S&S Arts and CraftsColchester, CT 06415Stumps Decorations forSpecial OccasionsSouth Whitley, IN 46787Ð0305Triarco Arts & Crafts14650 28th Avenue N. 84
\b\t\n\t\f\rOptics: An EducatorÕs Guide With Activities in Science and Mathematics EG-2000-10-64-MSFC OpticsÐAn EducatorÕs Guide with Activities inScience, Mathematics, and Technology EducationTo achieve AmericaÕs goals in Educational Excellence, it is NASAÕs mission todevelop supplementary instructional materials and curricula in science, mathemat-ics, geography, and technology. NASA seeks to involve the educational communityin the development and improvement of these materials. Your evaluation andsuggestions are vital to continually improving NASA educational materials.Please take a moment to respond to the statements and questions below.You can submit your response through the internet or by mail. Send yourreply to the following internet address:http://ehb2gsfc.nasa.gov/edcats/educator_guideYou will then be asked to enter your data at the appropriate prompt.Otherwise, please return the reply card by mail. Thank you.1. With what grades did you use the educatorÕs guide?Number of Teachers/Faculty:______KÐ4______5Ð8______9Ð12______Community CollegeCollege/University:______Graduate______UndergraduateNumber of Students:______KÐ4______5Ð8______9Ð12______Community CollegeCollege/University:______Graduate______UndergraduateNumber of Others:______Administrators/Staff______Parents______Professional Groups______General Public______Civic Groups2. What is your home 5- or 9-digit zip code? __ __ __ __ __ - __ __ __ __3. This is a valuable educators guide. Strongly Agree Neutral Disagree Strongly Disagree4. I expect to apply what I learned in this educatorÕs guide. Strongly Agree Neutral Disagree Strongly Disagree5. What kind of recommendation would you make to someone who asks aboutthis educatorÕs guide? Average Poor Very Poor6. How did you use this educatorÕs guide? Background Information Critical Thinking Tasks Demonstrate NASA Materials Group Discussions Hands-On Activities Integration Into Existing Curricula Interdisciplinary Activity Lecture Team Activities Standards Integration Other: Please specify:7. Where did you learn about this educatorÕs guide? NASA Educator Resource Cemter NASA Central Operation of Resources for Educators (CORE) Institution/School System Fellow Educator Workshop/Conference Other: Please specify:8. What features of this educatorÕs guide did you find particularly helpful?9. How can we make this educatorÕs guide more effective for you?10. Additional comments:TodayÕs Date: Fold along the line and tape closed