Creating Computer Simulations and Animations in Physics

This site is dedicated to creating computer simulations in physics using various programming tools, including Java and JavaScript, with a special focus on Processing and the Easy JavaScript Simulation (EJS) tool.

Easy JavaScript Simulation (EJS) is an open-source tool, part of the Open Source Physics project, designed to simplify the creation of visual and interactive simulations with minimal coding—ideal for physicists, students, and researchers.

The tool supports both Java (.ejs files) and JavaScript (.ejss files) based simulations, making it versatile across platforms.

Use cases include educational demonstrations, scientific research, and even computer game prototypes.

Java-based simulations require a Java Virtual Machine (JVM) (JRE or JDK) installed on the computer, whereas JavaScript applets run directly in modern web browsers on devices including Android and iOS.

What’s New on Our Site?

• Dual-language EJS simulations: Step-by-step guides for creating simulations in both Java and JavaScript.
• File format insights: Differences between .ejs and .ejss files and their platform uses.
• Practical tutorials: Ready-to-use examples you can adapt for your own projects.
• Educational & scientific applications: Learn how EJS enhances teaching, research, and game development.

Why Use EJS?

• Simplicity: Rapid simulation creation with minimal code.
• Versatility: Supports both Java and JavaScript implementations.
• Cross-platform: JavaScript simulations run on almost any device.
• Open Source: Part of the Open Source Physics community.

Available Simulations

• Mass–Spring System
• Free Fall
• Vertical Launch
• Projectile Motion
• Circular Motion of a Particle
• Rotating Disk
• Rigid Body (Wheel) Motion

Additional Resources

• Java & Eclipse IDE: Tutorials on creating simulations with Java and the OSP library.
• Processing & p5.js: Guides for JavaScript-based animations using p5.js.

To start, download the latest EJS version and explore our tutorial library.

For more Java programming resources, visit Svet programiranja.

Java & Eclipse IDE Simulations

The Java language with the OSP (Open Source Physics) library enables advanced simulation creation. Java simulations (.ejs) allow fine control over physics, while minimizing boilerplate code.

If you are comfortable programming in Java and prefer IDEs like Eclipse, you can use standard Java libraries (e.g., javax.swing) to build custom simulation apps or even 2D/3D games.

Read more on: Java and simulations in physics.

Free Fall Simulation

This simulation is built with JavaScript and the p5.js library.

Looking for a Processing/Java version? See our projectile motion in Processing tutorial.

Horizontal Launch Simulation

This simulation is created with JavaScript and p5.js.

Learn how to build it in Processing/Java: Processing projectile motion.