LESSON PLANS
An Eye on Optics
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The goal of this lesson is to provide students with an open-ended opportunity to explore and work with materials, make and share observations, and build a foundational understanding of the relationship between gelatin shapes and light.
Introduce students to:
Age Levels: 10-14
Kits
Introduction
Activity 1
Activity 2
Activity 3
Activity 4
Activity 5
Activity 6
Design Challenge
Gelatin Recipe:
Materials
Process
Place design on a long table (or a few short tables placed together), add recyclables to the design and document how well each design sorts the recyclables into separate bins.
Design Challenge
You are part of a team of engineers given the challenge of designing a system of lenses to improve the sight of a patient. You’ll complete 6 activities to learn about the optics of lenses and the human eye.
Criteria
Constraints
Lesson requires six 45-60 minute class periods
INTRODUCING THE CHALLENGE
Summary
This lesson concludes with a design challenge, an open-ended project that encourages students to ask questions, take initiative, and think creatively. Engineering and design challenges provide context and meaning for employing the scientific process, developing technical knowledge and skills, and success in modern society.
To introduce this Design Challenge, students are presented with the goal of designing a system of lenses to improve the sight of a patient, students identify what they know and need to about the optics of lenses and the human eye to meet the challenge.
Background Skills and Knowledge
Set up for Activity
Divide students into teams of 2 or 3. Set the stage for a brainstorming session about the structure and function of lenses and the human eye.
Hold up a pair of eyeglasses.
Ask students to explain how glasses work to improve vision. Let students sketch their designs if it helps them express themselves more completely.
Explain to the class that this lesson ends with a design challenge. Explain that teams of students will design a system of lenses to improve vision for a patient. Explain that they will receive a model of a patient’s eye and will be tasked with designing a set of lenses to improve the patients’ vision.
Explain that teams will need to explain their design decisions based on data they collect while designing and testing lenses.
Have a Class Discussion – ask students:
Facilitating the Lesson
Project the images of a normal eye, a hyperopic, and a myopic eye on the screen and/or distribute a handout to teams with these images.
As a class, examine and discuss the differences between the images. Help students understand and note the following:
Distribute the scenario challenge and Student Worksheet #1, KWL chart to students. As a class, read and review the scenario. Allow students complete the KWL in pairs.
Summary and Reflection
As a class, review the scenario and ask volunteers to share from their KWL graphic organizers, and assess students’ understanding of the Design Challenge.
Ask students questions such as:
ACTIVITY 1: EXPLORE WITH LIGHT AND GELATIN (45-60 min)
Summary
The goal of this activity is for students to find and document the most effective way to observe and record the path of light as it leaves the light source and passes through and then out of the gelatin.
Students will have an open-ended opportunity to explore and work with the materials, make and share observations, and build a foundational understanding of the relationship between gelatin shapes and light. This open-ended exploration encourages creativity and problem solving useful to meet the final challenge of designing a lens system to improve vision.
Learning Outcomes
As a result of this activity students will be able to:
o With gelatin laid flat on the table
o With the gelatin NOT laid flat on the table
o 1 beam with Light Blox sitting on its wider side
o 1 beam with Light Blox sitting on it’s narrower side
o 3 beams at once
Prior Knowledge and Skills
Prior to beginning Activity 1:
Demonstrate/model how to measure and record the following:
Facilitating the Activity
Encourage creativity, exploration, and documentation
Throughout the period remind students to keep detailed records of their work to which they will refer it in the follow-up discussion.
Summarize and Reflect
Bring closure to the activity, encourage teams to share their work, and draw conclusions about the results.
What’s going on? Refraction definition and reference to more information. Optional: Kinesthetic Refraction Activity http://laserclassroom.com/products/kinesthetic-model-refraction/
ACTIVITY 2: EXPERIMENT WITH LENS SHAPE (45-60 min)
Summary
Students use the scientific process to uncover the qualitative relationship between light and the shape (concave, convex, square, circle) of a lens.
Learning Outcomes
As a result of this activity students will be able to Record the path of a single beam of light as it passes from the light source through a one side of a lens to the other side of a piece of gelatin; and draw conclusions about how light travels through a piece of gelatin with a
Prior Knowledge & Skills
Review at the beginning of the activity:
Set up for the Activity
Set up 4 stations
Prior to beginning the experiment: Explain the Scientific Process
Demonstrate/model how to measure and record the following:
Facilitate the activity
Summarize and Reflect
Bring closure to the activity, encourage teams to share their work, and draw conclusions about the results.
ACTIVITY 3: CREATE YOUR OWN LENSES – DESIGN AND DOCUMENT (45-60 min)
Summary
Students engage in directed exploration and use what they have learned so far, to document a process for how to reliably create/design concave and convex lenses of different sizes (widths).
Learning Outcomes
As a result of this activity students will be able to:
Prior to the activity, introduce, discuss or review
Facilitate the Activity
We strongly suggest that you take this class period to allow students a set amount of time (15-20 minutes) to struggle after you’ve shown them the shapes they are to create and given them their materials, rather than show students explicitly how to create the shapes. Once they have figured out how to create both a concave and a convex lens, they will document the process they used.
This challenge lays the foundation for understanding something basic, but not intuitive about these kinds of lenses – that they are derived from circles; and the more advanced understanding of the math that describes the properties of lenses relies on that understanding. This simple hands-on activity gives students an experiential, intuitive experience of the relationship between concave/convex lenses and circles.
Summarize and Reflect
ACTIVITY 4: EXPERIMENT WITH LENS SIZE (WIDTH) (45-60 min)
Summary
Using the process documented in the last class period, students engage in the scientific process to collect and record data and reach a conclusion about the impact of the dependent variable (width of lens) on the focal length. This is qualitative. The focal length gets longer or shorter, for example.
Understanding how the size (width) of the lens and the distance from the light source to the lens impacts focal length will help students to design a system of lenses to improve vision when they engage in the final challenge.
Prior to the activity, introduce, discuss or review
Demonstrate/model how to observe, measure and record
Facilitate the Activity:
Encourage systematic experimentation with light and lenses
Summary and Reflection
Ask teams to share their results. Hold a class discussion in which teams/individuals explain what they did, what they observed, and what sense they make of the results. Depending upon your approach you may want to use one of several active learning strategies or invite volunteers to draw or demonstrate their work at the front of the class.
ACTIVITY 5: EXPERIMENT WITH 2 LENS SYSTEMS (45-60 min)
Summary
As their final activity in preparation for the Design Challenge, students explore the behavior of light as it passes through various combinations of lens pairs. In the final challenge, students receive a diagram of a patient’s eye. One lens in the system will represent the lens found in the eye. Students will need to design one or more gelatin lenses to correct or improve the vision of their patient. The combination of lenses and their alignment need to focus light on the retina in the diagram of the patient’s eye.
Fill out the last part of the KWL chart FIRST.
Learning outcomes
As a result of this lesson, students will be able to:
Optional Math
https://www.khanacademy.org/science/physics/geometric-optics/lenses/v/multiple-lenssystems
Set the stage for experimenting with multiple lenses.
As a class, make a list of various instruments that use two or more lenses. If students suggest that the eye combined with eyeglasses is a lens system, explain that in the final lesson they will specifically address this combination. For now focus on instruments such as telescopes, microscopes, and binoculars.
Ask students to explain how they think the various instruments work and the relationships between the lenses and the lenses and light.
Explain that in this activity students will explore combinations of lenses on the behavior of light. Explain that they will pass a beam of light through two lenses to observe and record the results.
As a class discuss the many variables in the experiment, which to change, and which to keep the same. Some variables students should recognize include:
Facilitate the Activity
Explain that in this activity students need to keep careful records of their work. Depending on the time available, have all teams work with all combinations of lenses or break the class into “expert groups” and assign them the responsibility of reporting back to the class on the system they explored.
Teams should experiment with all or some of the following lens combinations:
Summary and Reflection
Bring closure to the experiments students performed. As a class, review the behavior of light as it passes through various pairs of lenses and the effect of changing the distance between pairs of lenses.
OPTIONAL
The Challenge: Design a 2-lens system to correct a vision problem (45-60 min)
Summary
This activity is focused on taking students through a process to create a lens system that corrects a vision problem. The goal of the activity lesson is not to design the perfect lens, but to understand what goes into solving a problem with the engineering process. Allow plenty of time and some structured boundaries to allow discovery to motivate exploration!
Prior Knowledge & Skills
Facilitate the Activity:
The goal is to allow students to understand that light can be manipulated with lenses — and that by doing this, they can solve problems. It will be challenging to get the lens just right. For more advanced students, you can introduce focal length, radius of curvature and index of refraction as mathematical methods of creating solutions rather than the “trial and error” approach that they are using.
The lesson can be done in as little as 1 class period for older students. However, to help students from feeling rushed and to ensure student success (especially for younger students), split the lesson into two periods giving students more time to brainstorm, test ideas and finalize their design. Conduct the testing and debrief in the next class period.
Internet Connections
Writing Activity
What other applications do lenses have in our world?
Note: All lesson plans in this series are aligned to the Computer Science Teachers Association K-12 Computer Science Standards, the U.S. Common Core State Standards for Mathematics, and if applicable also to the National Council of Teachers of Mathematics’ Principles and Standards for School Mathematics, the International Technology Education Association’s Standards for Technological Literacy, and the U.S. National Science Education Standards which were produced by the National Research Council.
Disciplinary Core Ideas
∙ PS4.B: Electromagnetic Radiation
o The path of light can be traced as straight lines, except at surfaces between different transparent materials (e.g., air and water, air and glass) where the light path bends between media. (MS-PS4-2)
∙ ETS1.A: Defining and delimiting Engineering Problems
o The more precisely a design task’s criteria and constraints can be defined, the more likely it is that the designed solution will be successful. Specification of constraints includes consideration of scientific principles and other relevant knowledge that are likely to limit possible solutions (MS-ETS1-1)
∙ ETS1.B: Developing Possible Solutions
o A solution needs to be tested, and then modified on the basis of the test results in order to improve it. MS-ETS-4)
Science and Engineering Practices
∙ Define a design problem that can be solved through the development of an object, tool, process or system and includes multiple criteria and constraints, including scientific knowledge that may limit possible solutions. (MS-ETS1-1)
∙ Develop and use a model to describe phenomena (MS-PS4-2)
∙ Analyze and interpret data to determine similarities and differences in findings. (MS ETS1-3)
Crosscutting Concepts
∙ Structure and Function
o Structures can be designed to serve particular functions by taking into account properties of different materials and how materials can be shaped and used (MS PSR-2)
o Structures can be designed to serve particular functions
Student Worksheet #1:KWL Chart
Student Name Date
Nurses, doctors, and engineers work together to design and build eyeglasses and other tools that improve vision. In this challenge you will design a system of lenses to improve a patient’s vision.
What do you need to know about the human eye and lenses to help improve someone’s vision?
Use the KWL graphic organizer below to list what you know, want to know and learned to design eyeglasses to improve someone’s vision
What I Know about Eyes and Lenses | What I Want to Know about Eyes and
Lenses |
What I Learned about Eyes and
Lenses |
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Student Worksheet 2:Materials and Experimental Set-up
Student Name Date
To complete the design challenge at the end of this unit, you will need ot know how to orient gelatin and lights to observe the path of light as it passes from the light source through a piece of gelatin
Using words and/or drawings, describe and document the path of light as it passes through gelatin: o With gelatin laid flat on the table o With the gelatin is NOT laid flat on the table
Student Worksheet 3: Ray Tracing
Using words and drawings, record the path of a single beam of light as it passes from the light source through a one side of a lens to the other side of a piece of gelatin; and draw conclusions about how light travels through a piece of gelatin with a
Student Worksheet 4: Eye Template
Lesson Plan Translation