The Exploratorium aimed to introduce and inspire, as well as teach. The museum exposed people to science by means of human perception. It provides a form of "educational sightseeing" as well as the understanding of the underlying principles. Its intention was not to replace a science class, but rather to inspire people to learn about science. The exhibits were arranged and structured to allow for free access to any part of the museum. Oppenheimer wanted people to be able to explore the museum and learn at their own pace, following a path that made sense to them and stimulated their curiosity. The idea of having people explore the museum in a way that appeals to everyone was an essential element. Instead of tour guides, fifteen to twenty college students or secondary students, as well as some adults, were employed as "explainers". They demonstrate the exhibits and explain the principles involved all while circulating among visitors, rather than guiding them along. Oppenheimer strove to make learning a fun and enjoyable experience for all.