Angry Arms

Spin the connected pendulums to explore chaos theory. Even if you try to start from exactly the same position, the final pendulum pattern will vary greatly.

Explanation

When weather predictions don’t always match up to what happens in real life, you can blame the unpredictability of chaos.

Chaotic systems are very sensitive to starting conditions. Small differences add up to big changes! This sensitivity makes a chaotic system’s outcome very hard to predict, especially over a long period of time.

Many natural phenomena are chaotic, including the weather and the human heartbeat when it begins to beat out of control. The study of chaos can also be applied to complex human systems such as the stock market.

Chaotic systems appear random, but actually contain patterns that can be studied. If you have all the information to feed into the patterns, you can predict the outcome of a chaotic system.

Extra Information

When the human heart begins to beat out of control such as in a heart attack, this is called fibrillation of the heart muscle. The heart stops beating regularly and instead goes into an unpredictable chaotic pattern of beats.

You may have seen defibrillators (two pads attached to a power pack) being applied to a heart attack victim’s chest on TV shows. These defibrillators send a powerful electric shock into the victim’s heart to overcome the chaotic electrical signals that are causing the heart to beat out of rhythm.

Researchers are examining a new system where smaller signals are sent into the victim’s heart. These take advantage of the patterns in the chaotic heart beat to bring the heart back under control.

Questions to Ask

Do you think weather forecasts could be more accurate? Why do you think they sometimes get it wrong? Are you surprised that they get it right so often?

Further Reading

• Getting to the heart of chaos: Researchers begin human trials of technique to control atrial fibrillation
  http://gtresearchnews.gatech.edu/newsrelease/HRTCHS.html
• What is chaos?
  http://order.ph.utexas.edu/chaos/
• Hewitt P G, 2002, Conceptual Physics, 9th edn, Addison Wesley, USA, p619

Angry Arms
Watch as the pendulums swing chaotically.

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