Labs for Refraction and Lenses

Lesson Plans || Learning Outcomes and Activities || Teacher Notes || Labs

 

We have a collection of ~150 labs in the Laboratory section of the website. Each lab was intended to be used with a lab notebook where students report their data and findings and state their conclusion with supporting evidence and reasoning. The intent was to provide a relatively clear purpose (or question) to students that they would need to address AND to limit the amount of directions. The hope is that the purposes and students' ability to design a procedure would drive the lab activity (in contrast to a detailed set of step-by-step procedures being the driving force of students' activity). As such, each of our labs comes with a Question and Purpose and a short paragraph describing what should be included in students' lab report. On occassion, students are also provided a graphic organizer, data table, or other item to be taped into their notebook. The following pages may be useful for those teachers who wish to adopt or simply trial our Labs with a Purpose approach:

Our Thoughts on the Approach || About Lab Notebooks || Teacher Guides for All Labs

 

 

Lab 1 - Refraction Action

Question:
When does light refract? Why does light refract? When does light not refract?

Purpose:
To describe when light refracts, why it refracts and when light does not refract?

A complete lab write-up includes a Title, a Purpose, a Data section, a Conclusion /Discussion section. The Data section should include an organized record of a collection of refraction observations and activities. The Conclusion/Discussion section should respond to the three parts of the purpose, providing an answer to each of the three questions. For each answer, evidence and/or examples from the Data section should be cited in support of the answer.

View: Teacher's Guide

 

Lab 2 - Direction of Bending

Question:
What rule could be developed to describe the direction of bending of a light ray as it crosses the boundary between two transparent media?

Purpose:
To determine the principle which would predict the relative direction of bending of a light ray as it crosses the boundary between two media (in either of the two directions).

A complete lab write-up includes a Title, a Purpose, a Data section, a Conclusion and a Discussion of Results. The Data section should include a trace of two or more prisms (rectangular or triangular) and the path of laser light from air, into, through and out of the prism. Normal lines should be constructed and the relative direction of bending with respect to the normal line should be discussed. The Conclusion should include a statement of the rule(s). The Discussion of Results section should make explicit reference to the diagrams in the Data section and discuss the logical connection between the evidence and the conclusion.

View: Teacher's Guide

 

Lab 3 - How Much?

Question:
What is the mathematical equation relating the angle in air to the angle in water for light refracting across the boundary from air into water?

Purpose:
To state the experimentally-derived equation relating the angle in air to the angle in water for light refracting across the boundary between air and water.

A complete lab write-up includes a Title, a Purpose, a Data section, a Conclusion and a Discussion of Results. The Data section should include a table of data with column headings and units, a graph of sinQ_air vs. sinQ_water. Linear regression should be performed for the graph and the slope, y-intercept, regression constant and equation should be reported. Class data for the slope of the line should be recorded and subsequently used in your Discussion of Results. The Conclusion should respond to the question raised in the Purpose of the lab (as always). The Discussion of Results section should include an error analysis in which you evaluate the reliability of your data and of your equation. An error analysis should always respond to the question how well did I do? and provide evidence for the answer. In this lab, an error analysis should include a comparison of the experimentally-derived equation with the equation which would be expected based upon textbook reading.

View: Teacher's Guide

 

Lab 4 - The Unknown n

Question:
What is the index of refraction for the materials which comprise a variety of prisms?

Purpose:
To determine the index of refraction of the unknown materials which comprise a variety of prisms.

A complete lab write-up includes a Title, a Purpose, a Data section and a Conclusion. The Data section should include an outline of at least two of the provided prisms; the path of the laser light into, through and out of the prism should be indicated by light rays. Proper constructions and measured angles should be included on each diagram in an effort to determine the index of refraction of the material of the prism. Measurements and calculations should be made (and clearly shown) for the entry and the exit boundary; an average nvalue for each prism should be reported. The Conclusion should respond to the question raised in the Purpose of the lab (as always).

View: Teacher's Guide

 

Lab 5 - A Critical Lab

Question:
At what angle does refraction cease to occur in such a manner that light undergoes total internal reflection?

Purpose:
To determine the critical angle for the water-air boundary and for the Lucite-air boundary.

A complete lab write-up includes a Title, a Purpose, a Data section, a Conclusion and a Discussion of Results. The Data section should include two diagrams - one for each boundary. The diagram should display a light ray approaching the boundary at the critical angle and the refracted ray at the appropriate angle. Critical angles should be recorded. The Conclusion should respond to the question raised in the Purpose. The Discussion of Results section should include a short error analysis and include percent error calculations for the two critical angle values.

View: Teacher's Guide

 

Lab 6 - Exploring Lenses Lab

Question:
At what angle does refraction cease to occur in such a manner that light undergoes total internal reflection?

Purpose:
To determine the critical angle for the water-air boundary and for the Lucite-air boundary.

A complete lab write-up includes a Title, a Purpose, a Data section, a Conclusion and a Discussion of Results. The Data section should include two diagrams - one for each boundary. The diagram should display a light ray approaching the boundary at the critical angle and the refracted ray at the appropriate angle. Critical angles should be recorded. The Conclusion should respond to the question raised in the Purpose. The Discussion of Results section should include a short error analysis and include percent error calculations for the two critical angle values.

View: Teacher's Guide

 

Lab 7 - The L•O•S•T Art of Image Description

Question:
How do the characteristics of images formed by converging lenses compare for various object locations?

Purpose:
To describe the relative location, orientation, size and type of the image produced of an object by a converging lens when the object is located at four strategic locations along the principal axis.

A complete lab write-up includes a Title, a Purpose, a Data section, a Conclusion/Discussion. The Data section should include a table in which you identify the observed (LOST) characteristics of the images for object positions beyond the 2F location, at the 2F location, between the F and 2F locations and inside F. The data table should be accompanied by a diagram depicting the strategic locations. The Conclusion/Discussion should include an organized paragraph in which you respond to the question raised in the Purpose of the lab.

View: Teacher's Guide || Data Table

 

Also Available ...

Physics teachers may find the following for-sale tools to be useful supplements to our Lesson Plan and Pacing Guide section:

 

1. Task Tracker Subscription (annual purchase)
   A subscription allows teachers to set up classes, add students, customize online assignments, view student progress/scores, and export student scores. Task Tracker accounts allow your students to begin assignments in class or at school and to finish them at home. View our Seat and Cost Calculator for pricing details.
    
2. The Solutions Guide
   We publish a free curriculum with >200 ready-to-use Think Sheets for developing physics concepts. The Solutions Guide is a download containing the source documents, PDFs of source documents, and answers/solutions in MS Word and PDF format. An expanded license agreement is included with the purchase. (Cost: $25 download)
    
3. Teacher Presentation Pack
   This is a large collection of downloadable content packed with nearly 190 Microsoft PowerPoint slide decks, the corresponding Lesson Notes (as PDF and fully-modifiable MS Word format), about 170 animations (in .gif, .png, and .mp4 file formats), a countless number of ready-to-use images (including the original source documents that would allow for easy modification of those images), and a license that allows teachers to modify and use all the content with their classes on password-protected sites (such as course management systems).  (Cost: $40 download)
    
4. Question Bank
   We distribute a Question Bank that includes more than 9300 questions neatly organized according to topic. The Question Bank is the perfect tool for busy teachers or new teachers. Even if you don't use the website with your classes, the Question Bank will assist you in quickly putting together quizzes, tests and other documents with high-quality questions that target student's conceptions of physics principles. And if you do use The Physics Classroom website, the Question Bank is the perfect complement to the materials found at the website. (Cost: $25 download)