engage with the exhibit, with opportunities for formulating a hypothesis, testing it, learning from the results of their experiments, and performing additional tests.

For example, at an APE exhibit called Downhill Race, visitors are asked to race two of six possible disks down parallel tracks to see which one rolls faster. Most visitors hypothesized that the heavier ones would roll the fastest, but disks with more of their mass located near the hub actually roll faster than those with more mass located near the rim. Visitors race disks to figure out which variable, mass or distribution of mass, is more important. Four of the disks have fixed masses, and two have masses whose location can be changed.

Among many visitors, this exhibit evoked excitement and brought out their competitive spirit. Because the participants wanted to win the race, many stuck with it, manipulating the masses until they figured out which rolled the fastest. After successfully completing the race, visitors appeared happy and energized.¹³

Interestingly, evaluators of this exhibit found that visitors who had misconceptions about which disk would roll the fastest were the most engaged by it. This intriguing finding may be attributable to the exhibit’s success in making visitors’ naïve understanding more salient to them and providing them with the opportunity to explore alternative explanations.

To continue to think about the challenges inherent in exhibit design, we now look at a different kind of exhibition. Called The Mind, it, too, was developed at the Exploratorium. The issue facing the designers was how to create an exhibition that explores how the mind—the most elusive and mysterious part of ourselves—functions in different situations.