Total Internal Reflection - Complete Toolkit

Objectives

1. To describe how the relative intensity of a reflected ray and refracted ray at a boundary is dependent upon the angle of incidence.
    
2. To define total internal reflection and to state the conditions that are required in order for a light ray to undergo total internal reflection.
    
3. To define the critical angle, to derive an equation for the critical angle from Snell's law equation, and to use the equation to calculate the critical angle for the boundary between two media.
    

 

Readings from The Physics Classroom Tutorial

1. The Physics Classroom Tutorial, Refraction and the Ray Model of Light Chapter, Lesson 3

 

Interactive Simulations

1. Refraction Interactive, The Physics Classroom
   
   This simulation from The Physics Classroom allows a learner to explore the reflection and refraction of light at a boundary. Several substances can be chosen as the "Top" and "Bottom" substance. A laser can be dragged to any angle and a ray directed towards the boundary. A protractor allows for the easy measurement of the angles of incidence, reflection and refraction. The brightness of the three rays are indicated on the display.Learners can quickly observe that increasing the angle of incidence leads to an increase in the angle of refraction but also to a dimmer refracted ray and a brighter reflected ray. The Interactive comes with a ready-to-use activity that directs the learner towards the key observations to be found in the Interactive.
   
   
   
   
    
2. Bending Light, PhET
   
   This Interactive tool allows the user to explore the reflection and refraction of light at a boundary. Users can choose from some pre-selected materials or choose a customized index of refraction value. Angles of incidence, reflection, and refraction can be measured with a built-in protractor. Light meters allow users to quantitatively measure the intensity of the reflected and refracted light relative to the incident light intensity. Other options are available that do not necessarily shine light upon the topic of total internal reflection.

 

Video and Animations

 

Labs and Investigations

Demonstration Ideas

 

Minds On Physics Internet Modules:

The Minds On Physics Internet Modules are a collection of interactive questioning modules that target a student’s conceptual understanding. Each question is accompanied by detailed help that addresses the various components of the question.

1. Refraction and Lenses, Ass’t RL5 -  Total Internal Reflection
2. Refraction and Lenses, Ass’t RL6 -  TIR and the Critical Angle

 
 
 

Concept Building Exercises:

1. The Curriculum Corner, Refraction and Lenses, Total Internal Reflection

 

 

Problem-Solving Exercises:

1. The Calculator Pad, Refraction and Lenses, Problems #13-#18
   
   Link: http://www.physicsclassroom.com/calcpad/refrn/problems

 

 

Science Reasoning Activities:

1. Reflection and Transmission
   
   Link: http://www.physicsclassroom.com/reasoning/refraction

Real Life Connections:

1. Passive Fiber Optics
   
   This multi-part tutorial provides a considerable wealth of detail on the guiding of a light beam through an optical fiber. It is an excellent source of information for teachers who wish to strengthen their understanding of fiber optics.
   
   
   
    
2. Rainbow Formation 
   
    The physics that underlies the formation of rainbows is extensively and systematically explained in this video by VSauce. In his usual intriguing manner, VSauce producer Michael Stevens describes several types of rainbows using a variety of images and explains the conditions under which they are formed. While there is a minimal amount of information about refraction and internal reflection, the video provides valuable information that answers a variety of our most curious students' questions.
   
    

 

Standards:

A. Next Generation Science Standards (NGSS)
 

• Different patterns may be observed at each of the scales at which a system is studied and can provide evidence for causality in explanation of phenomena.

• Models (e.g., physical, mathematical, computer models) can be used to simulate systems and interactions – including energy, matter, and information flows – between and within systems at different scales. 
• Develop and use models (physical, mathematical, and computer models) to predict the behavior of a system and design systems to do specific tasks.

• Algebraic thinking is used to examine scientific data and predict the effect of a change in one variable on another.

• Analyze data using tools, technologies, and/or models (e.g., computational, mathematical) in order to make valid and reliable scientific claims.

• Develop and use a model based on evidence to illustrate the relationships between systems or between components of a system.
• Use a model to provide mechanistic accounts of phenomena.

• Plan and conduct an investigation individually and collaboratively to produce data to serve as the basis for evidence, and in the design: decide on types, how much, and accuracy of data needed to produce reliable measurements.

• Construct an explanation that includes qualitative or quantitative relationships between variables that predict phenomena.
• Construct and review an explanation based on valid and reliable evidence obtained from a variety of sources (including students’ own investigations, models, simulations, and peer review) and the assumption that theories and laws that describe the natural world operate today as they did in the past and will continue to do so in the future.

• Make and defend a claim based on evidence about the natural world that reflects scientific knowledge and student-generated evidence.