An Orange-Scent Investigation
The Granite Saddle Trail has a sheltered map alcove where hikers plan their routes. A trail science club used its long counter to investigate orange scent. Club members could smell a freshly opened orange snack nearby, but they could not see orange-colored specks floating between the snack and their noses. They wondered how something from an orange could reach a person without being seen.
An adult prepared fresh orange peel for a comparison. Each trial used 10 grams of peel in the same kind of clear cup. One cover was mesh with small openings. The other was a solid lid that closed tightly. The mesh kept the pieces of peel inside the cup. The adult handled the peel, and nobody tasted the materials or put a nose against a cup.
The club marked three distances from the cup: 20, 60, and 100 centimeters. For each cover and distance, the adult set out a freshly prepared cup. Six volunteers waited away from the counter. After one minute, they took turns standing at the marked distance and reporting whether they could detect orange scent while breathing normally. The club counted yes reports, not how strong the scent seemed.
The club used the same six volunteers, peel mass, cup type, waiting time, and counter location throughout. The adult changed the cover and tested the three marked distances. Between trials, the adult removed the cup and aired the alcove until the volunteers reported no remaining orange scent. No fans were running during the trials. The order of the distances was mixed rather than tested from nearest to farthest.
The results appear below. During the mesh trials, the peel stayed inside the cup, and volunteers saw no orange specks in the air. The club now wants a model that explains these observations. In a particle model, drawn symbols stand for tiny bits of matter. A model is an explanation tool, not a photograph or a count of the actual particles.