Phun for Windows

Quick summary

Phun — a playful physics tool from Sweden — is a free, educational program that blends simplicity with entertainment. It’s especially engaging for students learning mechanics and other basic physical principles, and many teachers find it a useful classroom supplement.

What the program does

• Simulates two-dimensional objects in a sandbox-style environment.
• Lets you build shapes and observe how they respond to applied forces.
• Demonstrates realistic interactions such as collisions, fluid behavior and deformation.

Physical effects you can experiment with

• Viscosity (how fluids flow and resist movement)
• Elasticity (how materials stretch and bounce back)
• Inertia (resistance to changes in motion)
• Density (how mass is distributed in objects)
• Friction (surface resistance that slows motion)
• Gravity (constant pull that influences everything)

Design choices and limitations

The program focuses on 2D to keep the user interface approachable — which is why there’s no support for three-dimensional objects. That trade-off makes it easier to draw and manipulate items quickly, keeping the learning curve shallow.

Recent fixes and additions

• Water rendering has been greatly improved; transparent objects and behind-the-surface effects now display correctly.
• A convenient panning shortcut was added: hold both mouse buttons (left + right) to move the view at any time, even while drawing a polygon.
• Numerous stability and bug fixes have been applied across the app.

Languages and availability

• Spanish
• Portuguese
• German
• Czech

The application is free to use and demo videos are available online for a quick preview of its capabilities.

Background and recommended use

Phun began as a student project at Umeå University, which makes its polish and effectiveness all the more impressive. It’s a great hands-on companion for teaching or learning fundamental physics concepts in an interactive, entertaining way.