LED Light & Optical Set

Transcription

1 LED Light & Optical Set Teacher s Notes

2 it is is designed The designed Light Box for for and helping helping Optical student student Kit is designed to to understand understand to help students the the Laws Laws to better of of Refraction understand Refraction / the / Reflection Reflection Laws of Refraction w ow and Reflection and how they govern the behaviour of Using the activity cards, dual they they governing governing the the refraction refraction / / reflection reflection of of light. light. With With our our interactive interactive activities activities colour 3-ray light box and optical components, students can observe how light bends as it passes from dual, dual colour colour one 3-ray 3-ray medium light light to another. box box && The lenses lenses LED set, set, ray box it it is also can can easily easily a great demonstrate demonstrate tool the the for helping students bending bending of of to understand s how it it passes passes lenses work from from in one one the human medium medium eye to to and another. another. optical instruments It It is is also also a a and great great how tools tools for helping students they play for an helping important students role in life and derstand how lenses in human eye and optical insturments play an important role rstand modern how technology lenses in today. human eye and optical insturments play an important role & technology technology today. Note: The Ray today. Box contains a magnet (enclosed at the rear of the box) so it can be placed onto a magnetic white board for demonstration purposes. w to to use? Instructions for use ow to use? 1. The LED ray box requires Each Each button button requires requires three three batteries batteries (not (not three batteries (not included). included). Loosen Loosen the the screw screw from from the the battery battery included). Loosen the screw Note: Do not mix old from the battery compartment compartment compartment cover cover using using a a screwdriver. screwdriver. Insert Insert and new batteries. cover using a screwdriver. Insert the the batteries, batteries, close close the the cover, cover, and and then then Do secure secure not mix alkaline, the batteries, close the cover, the the cover cover by by tightening tightening the the screw. screw. standard (carbon-zinc), and then secure by tightening Note: Note: or rechargeable (nickel- Do Do not mix old and new batteries. Do not not mix old and new batteries. Do not the screw. mix mix alkaline, standard (carbon-zinc), cadmium) or batteries. alkaline, standard (carbon-zinc), or rechargeable rechargeable (nickel-cadmium) batteries. (nickel-cadmium) batteries. 2. Separate switches operate 3 individual LED light sources each providing dual colour (white or red) Light Ray in Red Light Light Ray Ray in in Red Red Light Ray in White Light Light Ray Ray in in White White * 3 individual * 3 individal individal light rays in light light ray in dual ray colour in dual dual colour colour Co libration : : Calibration Before starting the activities, locate the optical centre by using lens C (the thick double convex lens). By e starting starting switching the the on activities, activities, the single please please middle white locate locate light the the beam optical optical you centre centre will see the by by moving moving light passes up up through / / down down the lens and is e lens lens refracted. If off centre, adjust its position so that the light passes straight through it. *Si *Si *Ad *Ad by by Cop Cop Optical centre Optical Optical centre centre P.1 P.1

3 Acrylic Block G ontains Components x 1pc 1x Ray box with 3 LED dual colour light sources (white or red) REFRACTION BY A SEMICIRCULAR BLOCK 1 Ray Box x 12pcs PLACE THE BLOCK HERE Zone A Zone B G 90 9x Pupil activity cards *Single light beam only *Adjust the angle of incidence i by moving the ray box as shown 2013 TickiT Educational Products. Morley Road, Tonrbidge, Kent, England. TN9 1RA REFRACTION BY A SEMICIRCULAR BLOCK 1 ACRYLIC BLOCK PLACE THE BLOCK HERE 1x Teacher s notes G x 9pcs Light Box 90 Zone A Zone B 90 *Single light beam only *Adject the angle of incidence i by moving the light box Copyright 2013 Creative Spot Learning Materials Limited. All rights reserved LED Light Box & Optical Kit e Laws of Refraction / Reflection Teacher s notes ht. With our interactive activities asily demonstrate the bending of a great tools for helping students turments play an important role tton requires three batteries (not d). Loosen the screw from the battery tment cover using a screwdriver. Insert eries, close the cover, and then secure er by tightening the screw. o not mix old and new batteries. Do not aline, standard (carbon-zinc), or eable (nickel-cadmium) batteries Contains P.10 12x Acrylic blocks (key code letters can be clearly seen under each lens in the display box) A: Planar Convex Lens B: Thin Double Convex Lens C: Thick Double Convex Lens D: Planar Concave Lens E: Thin Double Concave Lens F: Thick Double Concave Lens x 1pc G: Semicircular block H: Triangular prism (Isosceles right angled 45, 45, 90 degrees) I: Triangular prism x (Equilateral 1pc 60, 60, 60 degrees) J: Triangular prism (Scalene 30, 60, 90 degrees) K: Long rectangular block L: Rectangular block x 12pcs

4 Refraction by a Semicircular Block Learning objectives: 1) Finding the relationship between the angle of incidence i and the angle of refraction r. 2) Verify Snell s Law. Activity card 1 - Refraction by a Semicircular Block Semicircular acrylic block: G Ray box using single white light beam Snell s Law: n 1 n 1 sin 1 = n θ 2 sin θ 2 θ 1 n 2 θ 2 : refractive index of medium 1 (air) : angle of incidence : refractive index of medium 2 (acrylic) : angle of refraction same plane. normal Place the semicircular acrylic block on Zone B Place the ray box on the position shown and switch on the central white light beam only Check that the incident ray, the refracted ray and the normal all lie in the same plane. air medium r i 1. Rotate the light box as shown on the card keeping the light beam in line with the centre of the circular protractor and measure the angle of incidence and the angle of refraction in different positions. 2. How is the angle of incidence i related to the angle of refraction r? 3. Collect several sets of data for the incident ray & the refracted ray. 4. Plot sin i (angle of incidence) against sin r (angle of refraction) on a graph sin i sin r = refractive index of the medium

5 Total Internal Reflection Using a Semicircular Block Learning objectives: 1) Understand total internal reflection. 2) Identify the criteria for total internal reflection to occur. Activity card 1 - Refraction by a Semicircular Block Semicircular acrylic block: G Ray box using single white light beam Finding the critical angle c 1. Place the semicircular acrylic block on Zone A 2. Place the ray box on the position shown and switch on the central white light beam only. Start with the Ray Box in line with the centre of the block. Now rotate it as shown keeping the beam of light focused towards the centre of the circular protractor. 3. Move the light box and observe the position of the refracted ray when the angle of incidence is increased. 4. Note the critical angle (c) - the angle of incidence that results in an angle of refraction of Now observe what happens to the refracted ray when the angle of incidence is greater than the critical angle. air Light refracted (a) air c (b) c Critical Angle (C) air Light reflected Total internal reflection (c)

6 Refraction by a Rectangular Acrylic block Learning objective: To verify how light bends as it passes from one medium to another, obeying the laws of refraction. Activity card 2 - Refraction by a Rectangular Block Rectangular acrylic block: L Ray box using single white light beam 1. Place the Ray box as shown on card 2 and switch on the central white light only 2. Change the position of the ray box keeping the beam focused on the normal and observe how a light ray is refracted when it enters the block at different angles. 3. Observe how the angle of incidence affects the lateral displacement of the light ray. B incident ray emergent ray D Iateral displacement

7 Refraction by Prisms Learning objective: Recognize the characteristics of different kinds of prisms. Activity card 3 - Refraction by Prisms Triangular acrylic blocks: H, I, J Ray box using a single and multiple light beams Observe what happens when white light passes through prisms (H,I,J). 1. Place the Ray Box on the card and switch on a single beam (and then all three beams). Place each triangular prism on the circular target in turn and rotate them. 2. Observing how light rays passing through different prisms of different shapes are refracted. 3. Find out how light can be reflected using an isosceles right angled prism (H) to create a mirror. To do this switch on all three lights on the Ray Box and place the isosceles prism in front of the beams as shown. angle of deviation D incident ray emergen A spectrum is formed which consists of seven characteristic rainbow colours Experiment with different prisms as the light ray passes through them to see how it is refracted Use the right-angled prism to show how it can be used as a mirror

8 Light Pipes Learning objectives: 1) Observe and understand total internal reflection. 2) Identify the criteria for total internal reflection to occur. Activity card 4 - Light Pipes Rectangular acrylic block: K Ray box using a single white light beam 1. Change the position of the incident ray until the critical angle (c) is reached. 2. Observe what happens to the refracted ray when the angle of incidence is greater than the critical angle. 3. Observe the light ray travelling inside the acrylic block (light pipe) due to total internal reflection. Q cladding P P Q core This experiment shows how a light ray runs along the inside of a fibre optic cable using internal reflection.

9 Concave Lenses Learning objective: Recognize the characteristics of different kinds of concave lenses (planar concave & double concave) Activity card 5 - Lens - Concave Convex acrylic blocks: D,E,F Ray box using all three white light beams 1. Observe how a ray parallel to the principal axis is refracted. 2. Observe how a ray passing through the principal focus is refracted. 3. Use different curvatures of lenses to see how they affect the position of the focal point. ove? O (1) (2) (3) F 1 l C F

10 Convex Lenses Learning objective: Recognize the characteristics of different kinds of convex lenses (planar convex & double convex) Activity card 6 - Lens - Convex Convex acrylic blocks: A,B,C Ray box using all three white light beams 1. Observe how a ray parallel to the principal axis is refracted. 2. Observe how a ray passing through a principal focus is refracted. 3. Use different curvatures of lenses to see how they affect the position of the focal point. (1) F 1 (3) (2) C F l

11 The Human Eye Learning objectives: 1. To understand the optical aspect of a normal, short-sighted and long-sighted eye. 2. How optical problems can be corrected by using suitable optical lenses. 3. Demonstrate how objects can be focused from the near point to the far point. Activities cards 7, 8 & 9: The Human Eye The Human-Eye Short Sight The Human Eye-Long Sight Acrylic blocks: A, B, C, D, E, F Ray box using 3 white beams. 1. Use the lenses to explore how light from a distant object is focused for a short-sighted person. 2. Use the lenses to explore how light from a near object is focused for a long-sighted person. 3. Use different lenses to see how focal point inside the eye can be corrected for a person with a shortsight or long-sight problem? Normal eye sight - Card 7 You will need to find the correct lens to focus the beams onto the back of the retina by placing them here Short sighted eye - Card 8 Long sighted eye - Card 9

12 2013 TickiT Educational Products. Morley Road. Tonbridge. Kent. TN9 1RA. Pages of this guide and pupil work-cards may be photocopied for use within the purchasing establishment only.