Chaos Experiment

Product Code: EX-5523A


The chaotic behavior of a driven nonlinear pendulum is explored by graphing its motion in phase space and by making a Poincare plot. These plots are compared to the motion of the pendulum when it is not chaotic.

The oscillator consists of an aluminum disk connected to two springs. A point mass on the edge of the aluminum disk makes the oscillator nonlinear. The frequency of the sinusoidal driver can be varied to investigate the progression from predictable motion to chaotic motion. Magnetic damping can be adjusted to change the character of the chaotic motion. The angular position and velocity of the disk are recorded as a function of time using a Rotary Motion Sensor. A real-time phase plot is made by graphing the angular velocity vs. the displacement angle of the oscillation.

The Poincare plot is also graphed in real time and superimposed on the phase plot. This is achieved by recording the point on the phase plot once every cycle of the driver arm as the driver arm blocks a photogate.

PASCO Advantage: PASCO Capstone can graph the motion in phase space and superimpose the Poincare plot in real time, showing students how the motion in phase space relates to actual motion of the oscillator.


  • Nonlinear oscillator
  • Chaotic motion
  • Phase space
  • Poincare plot


Chaos Experiment


Software Required

This product requires PASCO software for data collection and analysis. We recommend the following option(s). For more information on which is right for your classroom, see our Software Comparison: SPARKvue vs. Capstone »

Interface Required

This product requires a PASCO Interface to connect to your computer or device. We recommend the following option(s). For a breakdown of features, capabilities, and additional options, see our Interface Comparison Guide »

Support Documents

Manual Downloads

Product Manuals for the Included Products

Rotary Motion Sensor Manual PS-2120A
(1.1 MB – .pdf – English)
Mechanical Oscillator-Driver Manual (ME-8750)
(139 KB – .pdf – English)
Large Rod Base Manual (ME-8735)
(46 KB – .pdf – English)
Photogate Head Manual (ME-9498A)
(275 KB – .pdf – English)
Experiment File
(31.8 MB – .zip – English)