Free online science and maths tools

Browser viewer for molecular structures that loads PDB, SDF and other files.

Web chemical structure editor that exports MOL, SMILES and other formats.

Web viewer for 3D structures of proteins, nucleic acids and ligands from PDB files.

Simulates a mass on a spring moving in two dimensions.

Compares tracks to find the shape giving the quickest slide between two points.

Simulates a car body on springs and dampers driving over bumps.

Models a pendulum on a cart driven along a track with graphs of the motion.

Simulates a chain of masses on springs and the waves along it.

Drives a pendulum to show chaotic motion and phase-space plots.

Two blocks joined by springs collide with walls and each other.

Runs two double pendulums from nearly equal starts to show sensitive dependence.

Shows how contact forces keep resting rigid bodies from sinking into each other.

Simulates circles and curved objects colliding and rolling.

Simulates a stick hanging from two springs and its swinging motion.

Runs two cars on a roller coaster track and tracks energy.

Two masses on springs in a line with graphs and a phase view.

Drops a chain of linked rigid bodies and lets it swing and settle.

Shows a pendulum balanced upright by vibrating its pivot.

Simulates a moon orbiting Mars with adjustable starting conditions.

Lets you move the pivot of a pendulum and watch how motion responds.

Shows bodies pulling on each other by gravity.

Rigid body simulation of a Newtons cradle with adjustable settings.

Simulates a pendulum clock with an escapement driving the pendulum.

Shows the pendulum direction field and trajectories in phase space.