Analog-To-Digital Science: Modeling Binary Coding and the CD Read System
written by
Alice Flarend
edited by
Caroline Hall
This five-day lesson module for high school physics uses modeling and hands-on investigation to explore how digital signals are created from analog information. Students will use art as an analogy to differentiate analog and digital media, choose sampling rates and apply mathematics, and encode/decode words in binary. In the culminating activity, learners build a working model of a CD player that uses laser light to read a word coded as a binary message. The lesson can be adapted for learners with little or no background in binary number systems. Materials include laser pointer, smartphone light meter, motorized toy car (to rotate the CD), blank compact discs, and converging lenses.
Analog-To-Digital Science: Modeling Binary Coding and the CD Read System by Alice Flarend
Waves and Their Applications in Technologies for Information Transfer (HS-PS4)
Students who demonstrate understanding can: (9-12)
Evaluate questions about the advantages of using a digital transmission and storage of information. (HS-PS4-2)
Communicate technical information about how some technological devices use the principles of wave behavior and wave interactions with matter to transmit and capture information and energy. (HS-PS4-5)
Disciplinary Core Ideas (K-12)
Wave Properties (PS4.A)
Information can be digitized (e.g., a picture stored as the values of an array of pixels); in this form, it can be stored reliably in computer memory and sent over long distances as a series of wave pulses. (9-12)
Information Technologies and Instrumentation (PS4.C)
Multiple technologies based on the understanding of waves and their interactions with matter are part of everyday experiences in the modern world (e.g., medical imaging, communications, scanners) and in scientific research. They are essential tools for producing, transmitting, and capturing signals and for storing and interpreting the information contained in them. (9-12)
Crosscutting Concepts (K-12)
Scale, Proportion, and Quantity (3-12)
The significance of a phenomenon is dependent on the scale, proportion, and quantity at which it occurs. (9-12)
Systems and System Models (K-12)
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. (9-12)
NGSS Science and Engineering Practices (K-12)
Analyzing and Interpreting Data (K-12)
Analyzing data in 9–12 builds on K–8 and progresses to introducing more detailed statistical analysis, the comparison of data sets for consistency, and the use of models to generate and analyze data. (9-12)
Analyze data using tools, technologies, and/or models (e.g., computational, mathematical) in order to make valid and reliable scientific claims or determine an optimal design solution. (9-12)
Developing and Using Models (K-12)
Modeling in 9–12 builds on K–8 and progresses to using, synthesizing, and developing models to predict and show relationships among variables between systems and their components in the natural and designed worlds. (9-12)
Develop and use a model based on evidence to illustrate the relationships between systems or between components of a system. (9-12)
Engaging in Argument from Evidence (2-12)
Engaging in argument from evidence in 9–12 builds on K–8 experiences and progresses to using appropriate and sufficient evidence and scientific reasoning to defend and critique claims and explanations about natural and designed worlds. Arguments may also come from current scientific or historical episodes in science. (9-12)
Construct an oral and written argument or counter-arguments based on data and evidence. (9-12)
Obtaining, Evaluating, and Communicating Information (K-12)
Obtaining, evaluating, and communicating information in 9–12 builds on K–8 and progresses to evaluating the validity and reliability of the claims, methods, and designs. (9-12)
Communicate technical information or ideas (e.g. about phenomena and/or the process of development and the design and performance of a proposed process or system) in multiple formats (including orally, graphically, textually, and mathematically). (9-12)
Planning and Carrying Out Investigations (K-12)
Planning and carrying out investigations in 9-12 builds on K-8 experiences and progresses to include investigations that provide evidence for and test conceptual, mathematical, physical, and empirical models. (9-12)
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 and consider limitations on the precision of the data (e.g., number of trials, cost, risk, time), and refine the design accordingly. (9-12)
Using Mathematics and Computational Thinking (5-12)
Mathematical and computational thinking at the 9–12 level builds on K–8 and progresses to using algebraic thinking and analysis, a range of linear and nonlinear functions including trigonometric functions, exponentials and logarithms, and computational tools for statistical analysis to analyze, represent, and model data. Simple computational simulations are created and used based on mathematical models of basic assumptions. (9-12)
Use mathematical and/or computational representations of phenomena or design solutions to support explanations. (9-12)
<a href="https://www.compadre.org/portal/items/detail.cfm?ID=14688">Flarend, Alice. "Analog-To-Digital Science: Modeling Binary Coding and the CD Read System." Edited by Caroline Hall.. 2018.</a>
A. Flarend, Analog-To-Digital Science: Modeling Binary Coding and the CD Read System, 2018, <https://www.compadre.org/Repository/document/ServeFile.cfm?ID=14688&DocID=4872>.
Flarend, A. (2018). Analog-To-Digital Science: Modeling Binary Coding and the CD Read System. Retrieved April 2, 2025, from https://www.compadre.org/Repository/document/ServeFile.cfm?ID=14688&DocID=4872
Flarend, Alice. "Analog-To-Digital Science: Modeling Binary Coding and the CD Read System." Edited by Caroline Hall.. 2018. https://www.compadre.org/Repository/document/ServeFile.cfm?ID=14688&DocID=4872 (accessed 2 April 2025).
@techreport{
Author = "Alice Flarend",
Title = {Analog-To-Digital Science: Modeling Binary Coding and the CD Read System},
Month = {April},
Year = {2018}
}
%A Alice Flarend %T Analog-To-Digital Science: Modeling Binary Coding and the CD Read System %E Caroline Hall, (ed) %D April 12, 2018 %U https://www.compadre.org/Repository/document/ServeFile.cfm?ID=14688&DocID=4872 %O application/pdf
%0 Report %A Flarend, Alice %D April 12, 2018 %T Analog-To-Digital Science: Modeling Binary Coding and the CD Read System %E Hall, Caroline %8 April 12, 2018 %U https://www.compadre.org/Repository/document/ServeFile.cfm?ID=14688&DocID=4872
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Analog-To-Digital Science: Modeling Binary Coding and the CD Read System
Teacher's Guide: Analog-To-Digital
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