Fine-tuned experimentation and observation
   
 
The set of custom computer controls offer visitors finely-tuned manipulation of the characteristics of the magnetic fields. User controls include:
  • A toggle switch that determines whether the voltage being applied
    to each electromagnet's coil is a sin or a square wave.

  • A single "pause" button which freezes all signals.

  • Three potentiometers, one for controlling the frequency of the applied wave, one for controlling the amplitude of the applied wave, and one for controlling the relative phase relationship of this wave as applied to each of the four electromagnets.
  • A four channel LED dot-graph display shows the strength and polarity of the magnet field emanating from each of the electromagnets.
 
 
 
Installed in science museums throughout
the world, the popular Hotplates exhibit
provides a lively stage for magnetic experimentation and play.
 
Thought and theatre

 

Visitors can use the exhibit to learn about magnetism, motors, mechanical resonance, and mathematics, or simply enjoy it as a fun, interactive experience.

The HotPlates platform consists of a shiny, horizontal stainless steel surface, inlaid with 4 sand-blasted circles. Four concealed computer-controlled electromagnets in a square array underlie the platform. Computer controls on the front of the exhibit offer visitors diverse ways to alter the magnetic field with dials and switches.

A bin beside the exhibit contains a diverse collection of items that visitors are invited to place on the platform. Once placed "on stage", the items respond to the magnetic fields, their behavior changing as visitors experiment with the controls. The range of different bin objects provides everyone with something of interest. A few examples of objects in use with current exhibits -

  • A glove whose magnet-filled fingers undulate in an eerie lifelike manner.

  • A lazy susan with attached bar magnet that functions identically to the rotor of an electric motor.

  • Compasses showing the magnetic field

  • Slinkies exhibiting resonance

  • Little toy chicks with metal feet that tap out a beat

Museum staff can add to the bin items over time (or invite visitors to invent new objects!). Objects can be designed to produce fun or eerie theatrical effects, as well as to demonstrate scientific principles.