Virtual Measurement of e/m Lab

Interactive courseware module that addresses J.J. Thomson’s landmark experiment to measure the charge-to-mass ratio of the electron, e/m.
Updated 5 Dec 2023

Virtual Measurement of the Electron to Mass ratio

View on File Exchange or Open in MATLAB Online

MATLAB Versions Tested

Curriculum Module

Created with R2021a. Compatible with R2021a and later releases.


This curriculum module contains interactive MATLAB® live scripts and MATLAB® app that follow J.J. Thomson’s landmark experiment to measure the charge to mass ratio of the electron, e/m.


The app is a virtual replacement for the experimental apparatus commonly used in physics laboratories. The live script contains a manual for conducting the experiment. This lab includes background, pre-lab, virtual experiment, and data analysis sections and concludes with an application of the theory to mass spectrometry.

The instructions inside the live scripts will guide you through the exercises and activities. Get started with each live script by running it one section at a time. To stop running the script or a section midway (for example, when an animation is in progress), use the image_0.png Stop button in the RUN section of the Live Editor tab in the MATLAB Toolstrip.

Contact Us

Solutions are available upon instructor request. Contact the MathWorks teaching resources team if you would like to request solutions, provide feedback, or if you have a question.

Getting Started

Accessing the Module

On MATLAB Online:

Use the image_1.png link to download the module. You will be prompted to log in or create a MathWorks account. The project will be loaded, and you will see an app with several navigation options to get you started.

On Desktop:

Download or clone this repository. Open MATLAB, navigate to the folder containing these scripts and double-click on [virtual-measurement-of-the-electron-charge-to-m.prj](matlab: openProject("virtual-measurement-of-the-electron-charge-to-m.prj")). It will add the appropriate files to your MATLAB path and open an app that asks you where you would like to start.

Ensure you have all the required products (listed below) installed. If you need to include a product, add it using the Add-On Explorer. To install an add-on, go to the Home tab and select image_2.png Add-Ons > Get Add-Ons.


  • Curve Fitting Toolbox™
  • Symbolic Math Toolbox™


If you are viewing this in a version of MATLAB prior to R2023b, you can view the learning outcomes for each script here

image_3.png In this script, students will...
- Explain the forces present in the experimental apparatus
- Derive the physical relationships required to compute the e/m ratio
- Relate the underlying theory to mass spectrometry

Related Courseware Modules

Feel free to explore our other modular courseware content.

Educator Resources


Looking for more? Find an issue? Have a suggestion? Please contact the MathWorks teaching resources team. If you want to contribute directly to this project, you can find information about how to do so in the page on GitHub.

© Copyright 2023 The MathWorks™, Inc

Cite As

Emma Smith Zbarsky (2024). Virtual Measurement of e/m Lab (, GitHub. Retrieved .

MATLAB Release Compatibility
Created with R2020b
Compatible with R2020b and later releases
Platform Compatibility
Windows macOS Linux
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Version Published Release Notes

See release notes for this release on GitHub:


To view or report issues in this GitHub add-on, visit the GitHub Repository.
To view or report issues in this GitHub add-on, visit the GitHub Repository.