Highly Recommended
Like all our Science Reasoning Center activities, the completion of the Models of Light activity requires that a student use provided information about a phenomenon, experiment, or data presentation to answer questions. This information is accessible by tapping on the small thumbnails found on the bottom right of every question. However, it may be considerably easier to have a printed copy of this information or to display the information in a separate browser window. You can access this information from this page

The Standards
Models of Light probes the dual nature of light. The success and failure of the wave model of light and the particle model of light to explain reflection, diffraction, interference,and the photoelectric effect are explored. This NGSS-inspired task consists of five parts. Each part involves a different type of skill or understanding. Collectively, the five parts were designed to address the following NGSS performance expectation:

HS-PS4-3:
Evaluate the claims, evidence, and reasoning behind the idea that electromagnetic radiation can be described either by a wave model or a particle model, and that for some situations one model is more useful than the other

As a whole, the questions in this task address a wide collection of disciplinary core idea (DCI), crosscutting concepts (CCC), and science and engineering practices (SEP). There are 46 questions organized into 17 Question Groups and spread across the five activities. Each question is either a 2D or (preferrably) a 3D question. That is, the task of answering the question requires that the student utilize at least two of the three dimensions of the NGSS science standards - a DCI, a CCC, and/or an SEP.

The following DCI, SEPs, and CCCs are addressed at some point within Models of Light:

• Electromagnetic radiation (e.g. radio, microwaves, light) can be modeled as a wave of changing electric and magnetic fields or as particles called photons.  The wave model is useful for explaining many features of electromagnetic radiation, and the particle model explains others.

SEP 1.7:  Asking Questions and Defining Problems
Ask and/or evaluate questions that challenge the premise(s) of an argument, the interpretation of a data set, or the suitability of a design.

SEP 2.2:  Developing and Using Models
Design a test of a model to ascertain its reliability.

SEP 7.2: Engaging in Argument from Evidence
Evaluate the claims, evidence, and/or reasoning behind currently accepted explanations or solutions to determine the merits of arguments.

SEP 7.5: Engaging in Argument from Evidence
Make and defend a claim based on evidence about the natural world or the effectiveness of a design solution that reflects scientific knowledge, and student-generated evidence.

CCC 1.1Patterns
Different patterns may be observed at each of the scales at which a system is studied and can provide evidence for causality in explanations of phenomena.

CCC 3.1Scale, Proportion, and Quantity
The significance of a phenomenon is dependent on the scale, proportion, and quantity at which it occurs.

CCC 4.2: Systems and System Models
Models (e.g., physical, mathematical, computer models) can be used to simulate systems and interactions—including energy, matter, and information flows—within and between systems at different scales.

Here is our NGSS-based analysis of each individual activity of the Models of Light Science Reasoning task. The core ideas, crosscutting concepts, and science and engineering practices that we reference in our analysis are numbered for convenience. You can cross-reference the specific notations that we have used with the listings found on the following pages:

#### Part 1: Reflection

This activity consists of 18 forced-choice questions organized into six Question Groups that are delivered in order (unlike the usual randomized order). The questions guide students through an understanding of the particle nature and the wave nature of light and their ability to explain light reflection. Students earn the Trophy for this activity once they demonstrate mastery on all six Question Groups.

NGSS Claim Statement: Evaluate the claims, evidence, and reasoning behind the idea that the reflection of light can be described either by a wave model or a particle model.

 Target DCI(s) Target SEP(s) Target CCC(s) Electromagnetic Radiation PS4.B Electromagnetic radiation (e.g. radio, microwaves, light) can be modeled as a wave of changing electric and magnetic fields or as particles called photons.  The wave model is useful for explaining many features of electromagnetic radiation, and the particle model explains others. Engaging in Argument from Evidence SEP 7.2 Evaluate the claims, evidence, and/or reasoning behind currently accepted explanations or solutions to determine the merits of arguments. Systems and System Models CCC 4.2 Models (e.g., physical, mathematical, computer models) can be used to simulate systems and interactions—including energy, matter, and information flows—within and between systems at different scales.

#### Part 2: Diffraction

This activity consists of 16 forced-choice questions organized into four Question Groups. The questions focus on the experimental questions that can be asked in order to decide if diffraction is more aptly described by the wave model or the particle model of light. Students earn the Trophy for this activity once they demonstrate mastery on all four Question Groups.

NGSS Claim StatementAsk and evaluate questions that challenge the premise of the wave and particle models of light for diffraction at different scales.

 Target DCI(s) Target SEP(s) Target CCC(s) Electromagnetic Radiation PS4.B Electromagnetic radiation (e.g. radio, microwaves, light) can be modeled as a wave of changing electric and magnetic fields or as particles called photons.  The wave model is useful for explaining many features of electromagnetic radiation, and the particle model explains others. Asking Questions and Defining Problems SEP 1.7 Ask and/or evaluate questions that challenge the premise(s) of an argument, the interpretation of a data set, or the suitability of a design. Patterns CCC 1.1 Different patterns may be observed at each of the scales at which a system is studied and can provide evidence for causality in explanations of phenomena.

#### Part 3: Interference

This activity consists of a paragraph with 10 blanks. Students use a word bank to complete the paragraph. Feedback is immediate and students have an opportunity to correct their mistakes. Students earn the Trophy for this activity once accurately complete the paragraph.

NGSS Claim StatementDesign a test for the interference of light at different scales that will investigate the wave and particles models.

 Target DCI(s) Target SEP(s) Target CCC(s) Electromagnetic Radiation PS4.B Electromagnetic radiation (e.g. radio, microwaves, light) can be modeled as a wave of changing electric and magnetic fields or as particles called photons.  The wave model is useful for explaining many features of electromagnetic radiation, and the particle model explains others. Developing and Using Models SEP 2.2 Design a test of a model to ascertain its reliability. Scale, Proportion, and Quantity CCC 3.1 The significance of a phenomenon is dependent on the scale, proportion, and quantity at which it occurs.

#### Part 4: The Photoelectric Effect

This activity consists of 10 forced-choice questions organized into five Question Groups. Students evaluate the ability of the wave model and the particle model to explain the photoelectric effect. Students earn the Trophy for this activity once they demonstrate mastery on all five Question Groups.

NGSS Claim StatementEvaluate the claims, evidence, and reasoning as to whether the wave or particle model of light best describes the photoelectric effect.

 Target DCI(s) Target SEP(s) Target CCC(s) Electromagnetic Radiation PS4.B Electromagnetic radiation (e.g. radio, microwaves, light) can be modeled as a wave of changing electric and magnetic fields or as particles called photons.  The wave model is useful for explaining many features of electromagnetic radiation, and the particle model explains others. Engaging in Argument from Evidence SEP 7.2 Evaluate the claims, evidence, and/or reasoning behind currently accepted explanations or solutions to determine the merits of arguments. Systems and System Models CCC 4.2 Models (e.g., physical, mathematical, computer models) can be used to simulate systems and interactions—including energy, matter, and information flows—within and between systems at different scales.

#### Part 5: Evaluating Claims

This activity consists of a paragraph with 6 blanks. Students use a word bank to complete the paragraph. Feedback is immediate and students have an opportunity to correct their mistakes. Students earn the Trophy for this activity once accurately complete the paragraph.

NGSS Claim StatementEvaluate the claims, evidence, and reasoning behind the idea that light can be described either by a wave model or a particle model, and that for some situations one model is more useful than the other.

 Target DCI(s) Target SEP(s) Target CCC(s) Electromagnetic Radiation PS4.B Electromagnetic radiation (e.g. radio, microwaves, light) can be modeled as a wave of changing electric and magnetic fields or as particles called photons.  The wave model is useful for explaining many features of electromagnetic radiation, and the particle model explains others. Engaging in Argument from Evidence SEP 7.5 Make and defend a claim based on evidence about the natural world or the effectiveness of a design solution that reflects scientific knowledge, and student-generated evidence. Systems and System Models CCC 4.2 Models (e.g., physical, mathematical, computer models) can be used to simulate systems and interactions—including energy, matter, and information flows—within and between systems at different scales.

Complementary and Similar Resources
The following resources at The Physics Classroom website complement the Models of Light Science Reasoning Activity. Teachers may find them useful for supporting students and/or as components of lesson plans and unit plans.

The Physics Classroom Tutorial, Light Waves and Color Chapter

Physics Interactives, Light and Color: Electromagnetic Spectrum Infographic

Physics Interactives, Light and Color: Young's Experiment

Concept Builders, Light and Color: Spectrum

Minds On Physics, Light and Color Module: Mission LC1, EM and Visible Spectrum

Minds On Physics, Light and Color Module: Mission LC2, Polarization