Physical Science 2014-2015: Concave, and Convex Lowry and Vicki Lewis Physical Science 2014-2015: Concave, and Convex Mirrors Grade Level: 8 Duration: 100 minutes, or two 50 minute

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  • Joyce Lowry and Vicki Lewis

    Physical Science 2014-2015: Concave, and Convex Mirrors Grade Level: 8

    Duration: 100 minutes, or two 50 minute classes

    SOL(s): 9c The student will investigate and understand the characteristics of transverse waves. Key concepts include images formed by lenses and mirrors;

    Essential Knowledge: Plane, concave, and convex mirrors all reflect light. Convex mirrors diverge light and produce a smaller, upright mage.

    Concave mirrors converge light and produce an upright, magnified image if close and an inverted smaller image if far away.

    Instructional Objectives: SW will identify and compare images formed by concave and convex mirrors. SW draw diagrams of real and virtual images formed by each type of mirror. SW compare and contrast light behavior on plane, concave and convex mirrors.

    .

    Lesson

    Segment &

    Time Est.

    Materials

    Instructional Sequence

    Teacher/Student

    Actions Introduction

    (Predict,

    Explain)

    Power point with

    Images from plane,

    concave, and

    convex mirrors.

    Worksheet with

    prediction

    scenarios

    Predict: Elicit Students Prior Knowledge / Ideas:

    How are reflections formed? (Image 1 - Show on the screen an image of Eschers Hand with the

    Reflecting Sphere)

    What do you see in this picture? How is an image formed? Does the image in the sphere look

    exactly like real life? How is it different and how is it the same? How do you think the image in the

    globe is formed?

    Show on a screen images formed from plane mirrors and ask students to explain how a reflection is

    formed? Compare an image formed by a mirror and how we see objects in the room.

    Show on the screen images formed by convex and concave mirrors. Ask how these images are

    different from the images formed in the plane mirrors and how some of them might be similar to

    those formed by convex or concave mirrors.

    Display Mirror Mirage of Pig

    Pass out handout with predictions and question and allow student time to respond. Tell them they

    will have a chance after the lab activities to review their ideas, an or change them according the

    what they have learned and our discussions.

    T. show ppt Image 1 and

    elicits s. prior knowledge of

    The Law of Reflection,

    Diffuse and Regular

    Reflection in a plane mirror.

    T. lead discussion to elicit

    terminology - concave,

    convex, image, reflection, light

    rays, focal point

    Like the Escher image the

    mirage pig should provide

    interest and motivation. T. also

    lead discussion determine

    vocabulary - Real vs Virtual

  • Joyce Lowry and Vicki Lewis

    Explain: Discuss student predictions and answers in class discussion. While validating all

    responses, discuss those that seem most reasonable based on what students have been learning.

    S. make predictions and

    explanations for their

    predictions.

    T. leads discussion of s.

    predictions/explanations.

    Body

    (Observe)

    (Explain)

    Lab 1

    Spoons

    Pencil

    Worksheet

    Lab 2

    Optics Bench

    Light Source

    Convex and

    concave mirror

    Paper screen

    Worksheet

    Lab 3

    Computers or iPads

    Image simulator

    located at:

    http://tutor-homework.com/Physics_Help/lens_ray_simulation.html Worksheet

    Observe:

    1. Pass out lab activity questions/observation worksheet for each of the four labs. 2. Review safety rules (and if using glass mirrors, must wear goggles) 3. Review the directions for each of the activities and demonstrate how to use the simulator.

    1. Lab 1 S will describe the characteristics of images formed by both both convex and concave mirrors in terms of the images size, clarity, upright/upside down

    orientation, left/right orientation, and location (real and virtual).

    Q. Describe the appearance of your image in the mirror.

    Q. How does the appearance of a pencil point change as it moves closer to the

    bowl of a spoon?

    Q. If a flat mirror reverses right and left, why doesnt it reverse up and down

    2. Lab 2 S. will collect data and create a graph related to the placement of object and the formation of the image. S. will compare and contrast

    characteristics of images formed by convex and concave mirrors on a Venn

    Diagram.

    3. Lab 3 S. will take the settings from lab 3 and input them into the image simulator and use these to draw ray diagrams of formation of images.

    S work in small groups

    making observation about

    characteristics of images

    formed by concave and convex

    mirrors.

    T. circulates and asks S. about

    their observations and

    explanations for their

    observations and offers help

    with adjusting equipment and

    using simulations.

    http://tutor-homework.com/Physics_Help/lens_ray_simulation.htmlhttp://tutor-homework.com/Physics_Help/lens_ray_simulation.htmlhttp://tutor-homework.com/Physics_Help/lens_ray_simulation.htmlhttp://tutor-homework.com/Physics_Help/lens_ray_simulation.htmlhttp://tutor-homework.com/Physics_Help/lens_ray_simulation.html

  • Joyce Lowry and Vicki Lewis Closure

    (Explain,

    cont)

    Total Time =

    Explain (continued): Whole-class discussion of small group observations/explanations. Provide the scientific explanation to students. S. groups will share the results of the three labs with the

    whole class. The students will go back to the original prediction sheets, and revised their answers

    based on experiences with the labs.

    1. Images formed by convex mirrors diverge light and produce a smaller, upright image. 2. Images formed by concave mirrors converge light and produce an upright, magnified

    image if close and an inverted, smaller image if far away.

    3. Convex and concave images are the same because they are formed by the reflection of light.

    4. In a plane mirror you see a left to right, virtual image, that is right side up. Plane mirrors form virtual images, and curved mirrors can form both real and virtual images.

    5. 6.

    T. leads whole class

    discussion. S. share findings

    from lab activities.

    T. shows Power Point with key

    concepts and explanations.

    S. revise initial predictions

    based on their lab findings and

    whole class explanations (on

    original before and after

    worksheet).

    Assessment

    Plan:

    1. What kind of images are formed by convex mirrors? 2. What kind of images are formed by concave mirrors? 3. Compare and contrast images formed by concave mirrors, convex mirrors, and plane mirrors. 4. Draw a ray diagram to show the kind, size, and orientation of an image formed by a concave

    mirror.

    5. Draw a ray diagram to show the kind, size and orientation of an image formed by a convex mirror.

  • Joyce Lowry and Vicki Lewis

    Questions Predict (Before) Explain (After)

    1. What kinds of

    images are formed by convex mirrors?

    2. What kinds of

    images are formed by concave mirrors?

    3. How are the images the same or different?

    4. How do the images compare with those formed by plane mirrors?

    5. How does the distance of the object from

  • Joyce Lowry and Vicki Lewis

    Convex and Concave Mirrors Activities (Science Teachers Activities A Day Internet Excerpt)

    Mirrors can be flat or curved. When you see your image in a flat mirror, it is not distorted. When you look at your image

    in a curved mirror, light rays leave the mirror at a different angle from the approaching rays, so distortions result. Mirrors

    can be curved either inward or outward. Concave mirrors curve inward, like the interior of a bowl. Makeup mirrors are

    concave mirrors because they enlarge the image. Mirrors that curve or bulge outward are called convex mirrors. This type

    of mirror gives a wide field of view and is used in security mirrors in stores as well as the side mirror on cars and trucks.

    the mirrors affect the characteristics of the image: upside down, right to left, small to large?

    6. How do you think you would draw a ray diagram to show the image formed by the mirror in this diagram?

    7. How do you think you would draw a ray diagram to show the image formed by the mirror in this diagram?

  • Joyce Lowry and Vicki Lewis

    In this activity you will use the opposite sides of a shiny spoon to compare the images produced by concave and convex

    mirrors.

  • Joyce Lowry and Vicki Lewis

    Lab Activity 1 - Observing Images Produced by a Shiny Spoon

    Materials

    Shiny spoon

    Sharpened pencil

    Activity

    4. Pick up the spoon by its handle and hold it so you are looking at the caved-in or hollowed-out side. You are looking into a concave

    mirror. Describe the appearance of your image in the mirror. (Consider these characteristics in your description of the image: size,

    clarity, upright/upside down, left/right orientation.)

    5. With the spoon held at a distance from your face, move a pencil point slowly from your face toward the bowl of the spoon. Describe

    how the appearance of the pencil point changes as it moves closer to the bowl of the spoon.

    6. Turn the spoon around so you are looking at the back side of the bowl. You are looking at a convex mirror. Describe the appearance of

    your image in the mirror. (Consider these characteristics in y