# ALEX Lesson Plan

## When Light Gets in Your Eyes

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This lesson provided by:
 Author: Kathy Perkins System: Tuscaloosa City School: Tuscaloosa City Board Of Education The event this resource created for: ASTA
General Lesson Information
 Lesson Plan ID: 34769 Title: When Light Gets in Your Eyes Overview/Annotation: How does light affect sight?  In this lesson, students will observe how light reflects off objects and into the eye so we can see.  They will learn how the pupil controls the amount of light entering the eye, how we perceive color by sensing different wavelengths of light, and why objects look different in bright and dim light.This lesson results from a collaboration between the Alabama State Department of Education and ASTA.
Associated Standards and Objectives
Content Standard(s):
 Science SC2015 (2015) Grade: 4 8 ) Construct a model to explain that an object can be seen when light reflected from its surface enters the eyes. NAEP Framework NAEP Statement:: P4.2: Objects vary in the extent to which they absorb and reflect light and conduct heat (thermal energy) and electricity. NAEP Statement:: P4.9: Light travels in straight lines. When light strikes substances and objects through which it cannot pass, shadows result. When light travels obliquely from one substance to another (air and water), it changes direction. Unpacked Content Scientific And Engineering Practices:Developing and Using ModelsCrosscutting Concepts: Cause and EffectDisciplinary Core Idea: Waves and Their Applications in Technologies for Information TransferEvidence Of Student Attainment:Students: Construct a model and use it to explain that in order to see objects that do not produce their own light, light must reflect off the object and into the eye. Teacher Vocabulary:reflection opaque translucent transparent refractionKnowledge:Students know: Light enters the eye, allowing objects to be seen. Light reflects off of objects, and then can travel and enter the eye. Objects can be seen only if light follows a path between a light source, the object, and the eye.Skills:Students are able to: Construct a model to make sense of a phenomenon. Identify relevant components of the model including: light (including the light source), objects, the path that light follows, and the eye.Understanding:Students understand that: An object can be seen when light reflected from its surface enters the eyes.AMSTI Resources:AMSTI Module: Energy and Waves Alabama Alternate Achievement Standards AAS Standard: SCI.AAS.4.8- Identify a model that shows the path of light reflected from the surface of an object to be seen by the eye.

Local/National Standards:

Primary Learning Objective(s):

Students will draw, label, and explain a diagram that explains how an object can be seen when light reflected from its surface enters the eyes.

Students will:

• observe how the pupil changes size to control the amount of light entering the eye.
• describe how our eyes detect light rays in order to see.
• experiment with flashlights to see how the amount and direction of light affects our perception of color and ability to focus on objects.
Preparation Information
 Total Duration: 61 to 90 Minutes Materials and Resources: Flashlight for every 2 – 4 studentsFive colors of construction paper cut in approximately 2” by 11” strips (Use a paper cutter to cut a standard piece of construction paper into 4-5 strips. Each child needs a strip of each color.)  Science notebooks or note-taking guides from Attachments sectionpencilsmarker board, chart paper, or interactive white board for recording student responsessticky notesscissors for each studentOptional acceleration materials:copies of Electromagnetic Spectrum handout for each student (included in Attachments section)red, orange, yellow, green, blue, indigo, and violet yarn or paintglue for each student (if using yarn) or paintbrushes (if using paint) Technology Resources Needed: Computers with Internet access to How Light Affects Sight. This website provides to access all the student technology resources listed in this lesson. Projector Sample student illustration for evaluating student responsesRubric for evaluating student responses (Search for rubric 2636686 if the rubric does not automatically link.) Background/Preparation: We cannot see without light.  When our eyes adjust to a darkened room and we begin to see more, it is because our pupils dilate to allow more light to enter them.  However, we cannot see without light reflecting off an object into our eyes.  When light reflects off an object, some of the wavelengths may be absorbed while others are reflected.  We can only see the colors of the reflected wavelengths because those are the wavelengths that enter our eyes.  These wavelengths are detected by special cells in our eyes called cones, and then they are interpreted by the brain as color.Light travels in waves in a straight line unless an object changes the direction of the light through reflection or refraction.  The colors we see as the visible spectrum are a result of the way our brains interpret differences in wavelength of light.  Red light has the longest wavelength, which means it has the least amount of energy of any color in the visible spectrum.  Violet light has the shortest wavelength and the most energy.  The colors of the visible spectrum (red, orange, yellow, green, blue, indigo, and violet) always appear in order in a rainbow because a prism breaks the white light into its component colors from the least to the greatest amount of energy.  For more information, check out these websites:
Procedures/Activities: