Place the Planet!

I designed this “Place the Planet” interactive for the Planetarium Queue at the Maryland Science Center. The basic idea: to have the visitor line up the planets by increasing distance from the Sun. The positive reaction during prototyping led us to add a similar activity wherein the visitor arranges the planets in order of increasing mass, which we considered (and found to be) slightly more challenging.

Ejection Mechanism

As is frequently the case, the primary challenge was to make clear to the visitor the intent of the activity without a lot of explanatory text.  I’ve found that the simple presence of empty spaces goes a long way toward solving this problem.  The empty spaces in this interactive are quite conspicuous.  It took most visitors little time to gather that the pucks in the storage bin were meant to go in the slots.

Pucks in Tray

Another interactive problem: With the initial prototype, the panel would provide feedback (red light or green light) as soon as the puck was placed.  This arrangement caused people to simply move the puck around until it was in the right slot.  Then they would do the same with the other pucks until all the guesses were made.  I thought it would be more fun if the panel forced the visitor to make ALL the guesses and only then provide feedback.  But I needed the panel to provide a small prompt when all the pucks were in place, so I arranged the control circuit to illuminate the “Check Answer” button when the final puck was placed.  I was concerned that this might be too subtle a hint, but nearly all the visitors noticed that the button illuminated when all the pucks were in place.

Other issues were mostly technical and are addressed in each section below.

Circuit Operation


Control Panel


Clearing the Pucks


The Sun