Simulations in physics

Physicists deal with the natural forces of the world. We experience most of those forces here on Earth and observe their effects, but the forces themselves are invisible.

Physicists can use simulations to visualize the natural forces and see how different combinations of forces act on objects to produce different results.

Let's start with some simulations from the Khan Academy Physics content. Since the primary goal of these simulations is learning, they are simpler than ones used by actual physicists.

This simulation draws the magnetic fields around a magnet and is a great example of how computers let us visualize invisible forces. To see it from different angles, rotate around the magnet using your mouse.

This simulation shows what happens when a magnet is surrounded by iron filings. You can change the magnet angle with the left/right arrows and the magnet position with your mouse.

Animation studios and video game developers rely on physics to create realistic digital worlds. They typically use software with a built-in physics engine (a library of code that can simulate physical systems).

Let's check out a few simulations from the Khan Academy Pixar content that are simplified versions of the tools available in physics engines.

The simulation below visualizes water filling a container, using a model of water as a system of particles. Try to make the simulation appear more realistic by changing the particle properties and gravitational force.

The next simulation also uses a particle system to simulate a real-world phenomenon: fireworks. You can play around with 16 different parameters controlling the physical forces, launch position, and particle properties.

Animators use tools like this to fine-tune their special effects. Pixar has their own in-house 3D animation software that they've custom built for their movies, but anyone can use free open-source software such as Blender to create simular effects.

Quantum mechanics is a field in physics that attempts to explain the natural forces at the atomic and subatomic level. Not only are those forces invisible; they're also too minuscule for us to observe. Quantum physicists can use simulations to test out theories about the interaction of subatomic particles, such as quarks and gluons.

This animation is from a simulation of a quark-antiquark pair inside a vacuum of empty space:

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