DNA Science: Modeling Rosalind Franklin's Discovery with a Pen Spring
written by
Rebecca E. Vieyra
content provider:
Gregory A. Braun, Dennis Tierney, and Heidrun Schmitzer
In this interdisciplinary lab, students examine the diffraction pattern of a helical spring from a ballpoint pen to gain insight into how chemical physicist Rosalind Franklin determined the structure of DNA. The lesson was inspired by a 2011 article in The Physics Teacher magazine, which aims to provide students with a "sense for the usefulness of diffraction techniques." High school and undergraduate classrooms, of course, can't duplicate x-ray diffraction imaging techniques used by Franklin and her team. Yet, by projecting light rays from a laser pointer through a ballpoint pen spring, students can observe and analyze the unique x-shaped pattern produced by a helical structure. The Student Guide provides explicit directions for recording observations and using simple geometry to determine pitch angle of the diffraction patterns.
See Related Materials for a link to the full article in The Physics Teacher (free access).
Editor's Note:Although DNA is like a helical spring, the pitch angle of DNA is much greater than the pitch angle of most pen springs. The article in The Physics Teacher magazine explains these differences in detail.
Waves and Their Applications in Technologies for Information Transfer (HS-PS4)
Students who demonstrate understanding can: (9-12)
Use mathematical representations to support a claim regarding relationships among the frequency, wavelength, and speed of waves traveling in various media. (HS-PS4-1)
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)
[From the 3–5 grade band endpoints] Waves can add or cancel one another as they cross, depending on their relative phase (i.e., relative position of peaks and troughs of the waves), but they emerge unaffected by each other. (Boundary: The discussion at this grade level is qualitative only; it can be based on the fact that two different sounds can pass a location in different directions without getting mixed up.) (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)
Inheritance of Traits (LS3.A)
Each chromosome consists of a single very long DNA molecule, and each gene on the chromosome is a particular segment of that DNA. The instructions for forming species' characteristics are carried in DNA. All cells in an organism have the same genetic content, but the genes used (expressed) by the cell may be regulated in different ways. Not all DNA codes for a protein; some segments of DNA are involved in regulatory or structural functions, and some have no as-yet known function. (9-12)
Crosscutting Concepts (K-12)
Patterns (K-12)
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. (9-12)
Structure and Function (K-12)
The functions and properties of natural and designed objects and systems can be inferred from their overall structure, the way their components are shaped and used, and the molecular substructures of its various materials. (9-12)
Influence of Engineering, Technology, and Science on Society and the Natural World (K-12)
Technologies extend the measurement, exploration, modeling, and computational capacity of scientific investigations. (6-8)
Science is a Human Endeavor (3-12)
Science is a result of human endeavors, imagination, and creativity. (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)
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 representations of phenomena to describe explanations. (9-12)
NGSS Nature of Science Standards (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)
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)
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)
Teacher's Guide: DNA Science - Modifiable Word Version by Rebecca Vieyra
This is a printable Word version of the DNA Science-Rosalind Franklin's Discovery lesson plan/assessment. download 2421kb .docx
Published: June 4, 2016
Student Worksheet: DNA Science by Rebecca Vieyra
This is a printable student guide for distribution in the classroom. download 718kb .docx
Published: June 4, 2016
Waves and Their Applications in Technologies for Information Transfer (HS-PS4)
Students who demonstrate understanding can: (9-12)
Use mathematical representations to support a claim regarding relationships among the frequency, wavelength, and speed of waves traveling in various media. (HS-PS4-1)
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)
[From the 3–5 grade band endpoints] Waves can add or cancel one another as they cross, depending on their relative phase (i.e., relative position of peaks and troughs of the waves), but they emerge unaffected by each other. (Boundary: The discussion at this grade level is qualitative only; it can be based on the fact that two different sounds can pass a location in different directions without getting mixed up.) (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)
Inheritance of Traits (LS3.A)
Each chromosome consists of a single very long DNA molecule, and each gene on the chromosome is a particular segment of that DNA. The instructions for forming species' characteristics are carried in DNA. All cells in an organism have the same genetic content, but the genes used (expressed) by the cell may be regulated in different ways. Not all DNA codes for a protein; some segments of DNA are involved in regulatory or structural functions, and some have no as-yet known function. (9-12)
Crosscutting Concepts (K-12)
Patterns (K-12)
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. (9-12)
Structure and Function (K-12)
The functions and properties of natural and designed objects and systems can be inferred from their overall structure, the way their components are shaped and used, and the molecular substructures of its various materials. (9-12)
Influence of Engineering, Technology, and Science on Society and the Natural World (K-12)
Technologies extend the measurement, exploration, modeling, and computational capacity of scientific investigations. (6-8)
Science is a Human Endeavor (3-12)
Science is a result of human endeavors, imagination, and creativity. (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)
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 representations of phenomena to describe explanations. (9-12)
NGSS Nature of Science Standards (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)
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)
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)
<a href="https://www.compadre.org/precollege/items/detail.cfm?ID=14045">Vieyra, Rebecca E.. "DNA Science: Modeling Rosalind Franklin's Discovery with a Pen Spring." 2016.</a>
R. Vieyra, DNA Science: Modeling Rosalind Franklin's Discovery with a Pen Spring, 2016, <https://www.compadre.org/Repository/document/ServeFile.cfm?ID=14045&DocID=4402>.
Vieyra, R. (2016). DNA Science: Modeling Rosalind Franklin's Discovery with a Pen Spring. Retrieved April 4, 2025, from https://www.compadre.org/Repository/document/ServeFile.cfm?ID=14045&DocID=4402
Vieyra, Rebecca E.. "DNA Science: Modeling Rosalind Franklin's Discovery with a Pen Spring." 2016. https://www.compadre.org/Repository/document/ServeFile.cfm?ID=14045&DocID=4402 (accessed 4 April 2025).
Vieyra, Rebecca E.. DNA Science: Modeling Rosalind Franklin's Discovery with a Pen Spring. 2016. 4 Apr. 2025 <https://www.compadre.org/Repository/document/ServeFile.cfm?ID=14045&DocID=4402>.
@techreport{
Author = "Rebecca E. Vieyra",
Title = {DNA Science: Modeling Rosalind Franklin's Discovery with a Pen Spring},
Month = {June},
Year = {2016}
}
%A Rebecca E. Vieyra %T DNA Science: Modeling Rosalind Franklin's Discovery with a Pen Spring %D June 4, 2016 %U https://www.compadre.org/Repository/document/ServeFile.cfm?ID=14045&DocID=4402 %O application/pdf
%0 Report %A Vieyra, Rebecca E. %D June 4, 2016 %T DNA Science: Modeling Rosalind Franklin's Discovery with a Pen Spring %8 June 4, 2016 %U https://www.compadre.org/Repository/document/ServeFile.cfm?ID=14045&DocID=4402
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NGSS Standards (13)
DNA Science: Modeling Rosalind Franklin's Discovery with a Pen Spring
Teacher's Guide: DNA Science - Modifiable Word Version
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