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. These electromagnets are made by winding a coil of copper wire around an iron-based core and running variable electric current through the coil.
The exhibit's controls allow users change many parameters of the electric current in these coils.
The LED display shows, in each of its four columns, the amount of current in each electromagnet coil. If the topmost LED is lit, the electromagnet has its maximum positive current. If the bottommost LED is lit, the electromagnet has its maximum negative current. If the middle LED is lit, the electromagnet has 0 current.