Instruction Manual with Experiment Guide and Teachers’ Notes 012-09655A ® Beginning Optics System OS-8459 Op tics Ben ch
Basic Optics System T a b l e o f C o n t e n ts Contents Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 About the Equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 About the Experiments. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 Experiment 1: Color Addition . . . . . . . . . . . . . . . . . . . .
Beginning Optics System OS-8459 1 2 O 3 ic pt ch en sB 4 5 a b 6 c d e f Included Equipment Part Number 1. 1.2 m Optics Bench OS-8508 2. Viewing Screen OS-8467 3. +100 mm Mounted Lens 003-07204 4. +200 mm Mounted Lens 003-07205 5. Light Source OS-8470 6. Ray Optics Kit with: OS-8516A a. Storage Box/Water Tank 740-177 b. Mirror 636-05100 c. Hollow Lens OS-8511 d. Convex Lens 636-05501 e. Concave Lens 636-05502 f.
Beginning Optics System About the Equipment About the Equipment For detailed information on the Light Source and Ray Optics Kit, see the instruction sheets included with those components. Optics Bench Basic Optics components, such as mounted lenses and the adjustable lens holder, snap into the wide central channel of the optics bench. Place the base of the component on the bench and push down firmly to snap it in place. To move it, squeeze the tab on base and slide it along the bench.
Model No. OS-8459 About the Experiments 4. Snell’s Law (page 13): Determine the index of refraction of acrylic by measuring angles of incidence and refraction of a ray passing through the rhombus. 5. Total Internal Reflection (page 15): Determine the critical angle at which total internal reflection occurs in the rhombus. 6. Convex and Concave Lenses (page 17): Use ray tracing to determine the focal lengths of lenses. 7.
Beginning Optics System 6 About the Experiments ®
Model No. OS-8459 E x p e r i m e n t 1 : C o l o r A d d it i o n Experiment 1: Color Addition Required Equipment from Beginning Optics System Light Source Convex Lens from Ray Optics Kit Other Required Equipment Red, blue, and black pens Blank white paper Purpose Light source In Part 1 of this experiment, you will discover the results of mixing red, green, and blue light in different combinations. In Part 2, you will compare the appearance of red, blue, and black ink illuminated by red and blue light.
Beginning Optics System E x p e r i m e n t 1 : C o l o r A d d it i o n Part 2: Observing Colored Ink Under Colored Light Procedure 1. While you look away, have your partner draw two lines—one red and one black—on a sheet of white paper. One of the lines should be labeled A, and the other B, but you should not know which is which. Before you look at the paper, have your partner turn off the room lights and cover the red and green bars so the paper is illuminated only with blue light. Now look.
Model No. OS-8459 Experiment 2: Prism Experiment 2: Prism Required Equipment from Beginning Optics System Light Source Rhombus from Ray Optics Kit Blank white paper Purpose Incident ray The purpose of this experiment is to show how a prism separates white light into its component colors and to show that different colors are refracted at different angles through a prism.
Beginning Optics System 3. Experiment 2: Prism Rotate the rhombus until the angle (θ) of the emerging ray is as large as possible and the ray separates into colors. (a) What colors do you see? In what order are they? (b) Which color is refracted at the largest angle? (c) According to Snell’s Law and the information given about the frequency dependence of the index of refraction for acrylic, which color is predicted to refract at the largest angle? 4.
Model No. OS-8459 Experiment 3: Reflection Experiment 3: Reflection Required Equipment from Beginning Optics System Light Source Mirror from Ray Optics Kit Other Required Equipment Drawing compass Protractor Metric ruler White paper Purpose In this experiment, you will study how rays are reflected from different types of mirrors. You will measure the focal length and determine the radius of curvature of a concave mirror and a convex mirror. Part 1: Plane Mirror Procedure 1.
Beginning Optics System Experiment 3: Reflection the incoming and the outgoing rays and mark them with arrows in the appropriate directions. Questions 1. What is the relationship between the angles of incidence and reflection? 2. Are the three colored rays reversed left-to-right by the plane mirror? Part 2: Cylindrical Mirrors Theory mirror R A concave cylindrical mirror focuses incoming parallel rays at its focal point.
Model No. OS-8459 Experiment 4: Snell’s Law Experiment 4: Snell’s Law Required Equipment from Beginning Optics System Light Source Rhombus from Ray Optics Kit Other Required Equipment Protractor White paper Purpose The purpose of this experiment is to determine the index of refraction of the acrylic rhombus. For rays entering the rhombus, you will measure the angles of incidence and refraction and use Snell’s Law to calculate the index of refraction.
Beginning Optics System 7. E x p e r i m e n t 4 : S n e ll ’ s L a w On a new sheet of paper, repeat steps 2–6 with a different angle of incidence. Repeat these steps again with a third angle of incidence. The first two columns of Table 4.1 should now be filled. Table 4.1: Data and Results Angle of Incidence Angle of Refraction Calculated index of refraction of acrylic Average: Analysis 1. For each row of Table 4.
Model No. OS-8459 E xp e r i m e n t 5 : T o t a l I n t e r n a l R e f l e c t i o n Experiment 5: Total Internal Reflection Required Equipment from Beginning Optics System Light Source Rhombus from Ray Optics Kit Other Required Equipment Protractor White paper Purpose In this experiment, you will determine the critical angle at which total internal reflection occurs in the acrylic rhombus and confirm your result using Snell’s Law.
Beginning Optics System Experiment 5: Total Internal Reflection Procedure 1. Place the light source in ray-box mode on a sheet of white paper. Turn the wheel to select a single ray. 2. Position the rhombus as shown in Figure 5.3, with the ray entering the rhombus at least 2 cm from the tip. 3. Rotate the rhombus until the emerging ray just barely disappears. Just as it disappears, the ray separates into colors. The rhombus is correctly positioned if the red has just disappeared. 4.
Model No. OS-8459 Experiment 6: Convex and Concave Lenses Experiment 6: Convex and Concave Lenses Required Equipment from Beginning Optics System Light Source Convex Lens from Ray Optics Kit Concave Lens from Ray Optics Kit Other Required Equipment Metric ruler Purpose In this experiment, you will explore the difference between convex and concave lenses and determine their focal lengths. Theory When parallel light rays pass through a thin lens, they emerge either converging or diverging.
Beginning Optics System 18 E x p e r i m e n t 6 : C o n v e x a n d C o n c a ve L e n s e s 5. Nest the convex and concave lenses together and place them in the path of the parallel rays (see Figure 6.2). Trace the rays. Are the outgoing rays converging, diverging or parallel? What does this tell you about the relationship between the focal lengths of these two lenses? 6. Slide the convex and concave lenses apart by a few centimeters and observe the effect. Then reverse the order of the lenses.
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Beginning Optics System Experiment 7: Hollow Lens Repeat this step with water in different section of the lens to complete the first four rows of Table 7.1. Table 7.1: Predictions and Observations Lens surrounded by: Section 1 filled with: Section 2 filled with: Section 3 filled with: Water Air Air Air Water Air Air Air Water Water Air Water Air Water Water Water Air Water Water Water Air Prediction (converging or diverging) Observation (converging or diverging) Air Water 4.
Model No. OS-8459 Experiment 8: Lensmaker’s Equation Experiment 8: Lensmaker’s Equation Required Equipment from Beginning Optics System Light Source Concave Lens from Ray Optics Kit Other Required Equipment Metric ruler Purpose In this experiment you will determine the focal length of a concave lens in two ways: a) by direct measurement using ray tracing and b) by measuring the radius of curvature and using the lensmaker’s equation.
Beginning Optics System Experiment 8: Lensmaker’s Equation 2. Trace around the surface of the lens and trace the incident and transmitted rays. Indicate the incoming and the outgoing rays with arrows in the appropriate directions. 3. Remove the lens. To measure the focal length, use a ruler to extend the outgoing diverging rays straight back through the lens. The focal point is where these extended rays cross. Measure the distance from the center of the lens to the focal point.
Model No. OS-8459 Ex p e r i m e n t 9 : Ap p a r e n t D e p t h Experiment 9: Apparent Depth Required Equipment from Beginning Optics System Light Source Rhombus from Ray Optics Kit Convex Lens from Ray Optics Kit Mirror from Ray Optics Kit (used to block rays) Other Required Equipment Metric ruler White paper Very sharp pencil Purpose In this experiment, you will use two different methods to measure the apparent depth of the acrylic rhombus.
Beginning Optics System Experiment 9: Apparent Depth Paper Rhombus Line Figure 9.2 2. With both eyes, look down through the top of the rhombus. Does the line viewed through the rhombus appear to be closer? Close or cover one eye, and move your head side to side. Do you see parallax between the line viewed through the rhombus and the line viewed directly? 3. In this step, you will hold a pencil near the rhombus to determine the position of the apparent line.
Model No. OS-8459 Ex p e r i m e n t 9 : Ap p a r e n t D e p t h 2. Mark the place on the paper where the two rays cross each other. 3. Position the rhombus as shown in Figure 9.4. The “bottom” surface of the rhombus must be exactly at the point where the two rays cross. The crossed rays simulate rays that originate at an object on the “bottom” of the block. 4. Trace the rhombus and trace the rays diverging from the “top” surface. 5. Remove the rhombus and light source.
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Model No. OS-8459 Experiment 10: Focal Length and Magnification of a Thin Lens Experiment 10: Focal Length and Magnification of a Thin Lens Required Equipment from Beginning Optics System Light Source Bench Converging lens of unknown focal length1 Screen Other Equipment Metric ruler Optics Caliper (optional, for measuring image sizes), PASCO part OS-8468 1Instructors: see note on page 46.
Beginning Optics System Experiment 10: Focal Length and Magnification of a Thin Lens 2. Use the Thin Lens Formula (Equation 10.1) to calculate the focal length. f = _______________ Part II: Object Closer Than Infinity In this part, you will determine the focal length by measuring several pairs of object and image distances and plotting 1/d o versus 1/d i. 1m Screen Light source Lens Figure 10.1 Procedure 1.
Model No. OS-8459 Experiment 10: Focal Length and Magnification of a Thin Lens Table 10.1: Image and Object Distances Distance from light source to screen do di 1/d o 1/d i Image Size Object Size 100 cm 90 cm 80 cm 70 cm 60 cm 50 cm 3. For each intercept, calculate a value of f and record it in Table 10.2. 4. Find the percent difference between these two values of f and record them in Table 10.2. 5. Average these two values of f.
Beginning Optics System Experiment 10: Focal Length and Magnification of a Thin Lens 2. Calculate the absolute value of M (for each of the two lens positions) using your measurements of the image size and object size. Record the results in Table 10.3. image size M = ------------------------object size (eq. 10.3) 3. Calculate the percent differences between the absolute values of M found using the two methods. Record the results in Table 10.3. Table 10.
Model No. OS-8459 Experiment 11: Telescope Experiment 11: Telescope Required Equipment from Beginning Optics System Bench 2 Convex Lenses (+100 mm and +200 mm) Screen Paper grid pattern (see page 41), or a 14 × 16 grid of 1 cm squares Purpose In this experiment, you will construct a telescope and determine its magnification. Theory -di2 do1 di1 do2 Object Image Eye Lens +200 mm Lens +100 mm Figure 11.1 An astronomical telescope consists of two convex lenses.
Beginning Optics System Experiment 11: Telescope end of the optics bench and place the screen on the other end (see Figure 11.2). Their exact positions do not matter yet. +200 mm objective lens +100 mm eyepiece lens Screen Figure 11.2 Procedure 1. Put your eye close to the eyepiece lens and look through both lenses at the grid pattern on the screen. Move the objective lens to bring the image into focus. Objective Eyepiece lens lens Screen Right eye Left eye Figure 11.3 2.
Model No. OS-8459 1. Experiment 11: Telescope Measure d o1, the distance from the object (paper pattern on screen) to the objective lens. Table 11.1: Results Position of Objective Lens 2. Determine d i2, the distance from the eyepiece lens to the image. Since the image is in the plane of the object, this is equal to the distance between the eyepiece lens and the object (screen). Remember that the image distance for a virtual image is negative.
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Model No. OS-8459 E x p e r i m e n t 1 2 : M ic r o s c o p e Experiment 12: Microscope Required Equipment from Beginning Optics System Bench 2 Convex Lenses (+100 mm and +200 mm) Screen Paper grid pattern (see page 41), or a 14 × 16 grid of 1 cm squares Purpose In this experiment, you will construct a microscope and determine its magnification. Theory di2 do1 di1 do2 Object Image Eye Lens +100 mm Lens +200 mm Figure 12.1 A microscope magnifies an object that is close to the objective lens.
Beginning Optics System E x p e r i m e n t 1 2 : M ic r o s c o p e middle of the optics bench and place the screen near the end of the bench (see Figure 12.2). +100 mm objective lens +200 mm eyepiece lens Screen Figure 12.2 Procedure 1. Put your eye close to the eyepiece lens and look through both lenses at the grid pattern on the screen. Move the objective lens to bring the image into focus. Objective Eyepiece lens lens Screen Right eye Left eye Figure 12.3 2.
Model No. OS-8459 E x p e r i m e n t 1 2 : M ic r o s c o p e Analysis To calculate the magnification complete the following steps and record the answers in Table 12.1: 1. Measure d o1, the distance from the object (paper pattern on screen) to the objective lens. 2. Determine d i2, the distance from the eyepiece lens to the image. Since the image is in the plane of the object, this is equal to the distance between the eyepiece lens and the object (screen).
Beginning Optics System 38 E x p e r i m e n t 1 2 : M ic r o s c o p e ®
Model No. OS-8459 Experiment 13: Shadows Experiment 13: Shadows Required Equipment from Beginning Optics System (2 systems needed) 2 Benches 2 Light Sources 1 Screen Purpose The purpose of this experiment is to show the umbra (darker part) and the penumbra (lighter part) of the shadow. Set Up 1. Place the two optics benches beside each other. 2. Put one light source on each bench with the point source (circular hole) facing the other end of the bench. 3.
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Model No. OS-8459 Telescope and Microscope Test Pattern Telescope and Microscope Test Pattern Attach a copy of this pattern to the viewing screen for experiments 11 and 12.
Beginning Optics System 42 Telescope and Microscope Test Pattern ®
Model No. OS-8459 Teacher’s Guide Teacher’s Guide Experiment 1: Color Addition Note on procedure: Student’s expectation may differ from actual results. Encourage them to carefully observe the resulting colors and describe them accurately. Part 1, typical results: Table 1.1: Results of Colored Light Addition Colors Added Resulting Color red + blue + green slightly bluish-white red + blue pink-purple red + green yellow-orange green + blue bluish-green Part 1, answers to questions: 1.
Beginning Optics System Teacher’s Guide Experiment 3: Reflection Part 1, typical results: Table 3.1: Plane Mirror Results Angle of Incidence Angle of Reflection 9.0° 9.2° 16.8° 16.5° 19.0° 37.8° Part 1, answers to questions: 1. The angle of incidence and the angle of reflection are equal. 2. The three colored rays are not reversed by the mirror. Part 2, typical results: Table 3.2: Cylindrical Mirror Results Concave Mirror Convex Mirror Focal Length 6.2 cm 6.
Model No. OS-8459 Teacher’s Guide Experiment 6: Convex and Concave Lenses Typical results: Table 6.1: Results Focal Length Convex Lens Concave Lens 13.75 cm -12.1 cm (Step 5) When the lenses are nested together, parallel rays entering the lenses emerge nearly parallel; this tells us that the focal lengths are of approximately equal magnitude and opposite sign. (Step 6) By moving the lenses apart, the spacing of the rays can be changed, but they remain nearly parallel.
Beginning Optics System Teacher’s Guide Experiment 9: Apparent Depth Typical results: Table 1.1: Results d t n Part 1: Parallax method 2.12 cm 3.18 cm 1.50 Part 2: Ray-tracing method 2.23 cm 3.18 cm 1.43 Typical ray-tracing results are represented at 50% scale in Figure TG.1. The gray regions represent the actual light beams; the black lines and dots represent the student’s actual marks. Notice that this student traced along the edges of the light beams.
Model No. OS-8459 Part 2: Teacher’s Guide Typical results. Table 10.1: Image and Object Distances Distance from light source to screen do 1/d o di 1/d i -1) (cm-1) Image Size Object Size (cm) (cm) (cm 88.5 11.5 0.0113 0.0870 5.5 mm 42 mm 11.0 89.0 0.0909 0.0112 81 mm 10 mm 78.3 11.7 0.0128 0.0855 11.3 78.7 0.0885 0.0127 68.0 12.0 0.0147 0.0833 11.5 68.5 0.0870 0.0146 57.7 12.3 0.0173 0.0813 11.9 58.1 0.0840 0.0172 47.1 12.9 0.0212 0.0775 12.3 47.7 0.
Beginning Optics System Teacher’s Guide Experiment 11: Telescope Typical results: Table 11.1: Results Answers to questions: Position of Objective Lens 63.4 cm Position of Eyepiece Lens 102.2 cm Position of Screen 0.0 cm Observed magnification -5 d o1 63.4 cm d i2 -102.2 cm d i1 29.2 cm d o2 9.6 cm Calculated Magnification -4.9 Percent Difference 2% 1. The image is inverted. 2. It is a virtual image.
Model No. OS-8459 Teacher’s Guide tual image, viewed through the eyepiece lens, coincides with the virtual image of the grid pattern viewed through both lenses. Further study, Increasing Magnification: As the objective lens is moved closer to the object, the eyepiece must be moved further away. In practice, the objective can be moved to within about 13 cm before distortion from lens aberrations becomes significant. The theoretical limit is 10 cm, or the focal length of the objective lens.
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Model No. OS-8459 Technical Support Technical Support For assistance with any PASCO product, contact PASCO at: Address: PASCO scientific 10101 Foothills Blvd. Roseville, CA 95747-7100 Phone: 916-786-3800 (worldwide) 800-772-8700 (U.S.) Fax: (916) 786-3292 Web: www.pasco.com Email: support@pasco.com Limited Warranty For a description of the product warranty, see the PASCO catalog.
