How does smell travel?

On Day 1 of the workshop, five girls gathered at Tufts to talk about smell. As they peeled and ate clementines, the facilitators asked them, "How does the smell get from the orange to your nose?"

Drawing smell

The girls noted differences in how the clementines and the oranges smelled. They also remarked that the oranges smelled stronger when peeled. The facilitators then asked the girls to draw how smell got from the orange to their noses. Nicole and Nell described their drawings:

Nicole and Nell's drawings show two ideas that emerged about “how smell moves”:

  1. One idea was that when someone peels the orange, the smell spreads throughout the room. When a person breathes in, they smell the “scent” that is around the nose.
  2. Another idea is that smell moves when someone breathes in, creating a channel that brings smell from the object to their nose.

While Nicole and Nell's drawings showed smell spreading to other places in the room, the other three drawings depicted smell as moving directly from the orange to the person breathing in.

The facilitators then asked the girls to compare their drawings and to consider whether they thought smell would spread throughout the room.

Although some of their representations showed smell going directly to the nose, the girls agreed that smell actually goes everywhere throughout the room. But they still had questions: Does breathing create a path from the orange to the smeller? Is smell the same strength everywhere in the room? What role does the brain play in processing smells?

Animating smell

Later during Day 1, the facilitators asked the girls to create stop-motion animations to show how smell moved. Nicole, Eileen, and Nell created the animation on the left and Arianna and Aisha created the one on the right.

 

 

In the animation on the left, the girls use discrete pieces that first move outward as the orange is peeled. As the person breathes in, the pieces move directly to their nose. In the animation on the right, scent is represented by continuous lines that curl in different directions, but still lead to the person's nose. This animation emphasizes that the brain needs to recognize the smell as part of the process.

They finished Day 1 expanding on their ideas about how they were able to recognize smell, drawing on their personal experiences with familiar and unfamiliar smells.

What is smell made of?

Day 2 started with the girls returning to their discussions about smell while sitting around the dining room table at Nicole’s house. They began talking about smelling foods cooking in the adjacent kitchen - like soups, stews, and grilled food. They recalled that some foods are “pungent” and others they don’t tend to notice, like cereal.

The girls decide that to understand how smells vary in intensity, they need to figure out what smell is made of. They come up with some ideas:

After discussing their ideas about smell, the girls invented the word “oogtom” to refer to the oogie and atom combination. They made “intertwined twirlies” of atoms and oogies out of pipe cleaners. The facilitators helped the girls in translating their ideas into rules for how each oogtom should behave within the simulation software. They decided that 3 oogtoms should be produced each second, and then "fan out" in all directions.

Simulating smell

On Day 3, the girls started working with a computer software, StageCast, to simulate their ideas about how smell moves. StageCast offered a collection of objects to program, and the girls chose a princess to play the role of “smeller.” They also picked spherical objects to represent the orange and oogtoms.

Even though they had decided in their earlier model that the oogtoms should "fan out," it is difficult to program objects in StageCast to move in all directions. So, they created a rule that the oogtoms should move "up" and "to the right." This directionality mirrors the set-up from their drawings, where the orange is at the bottom left corner, and the nose is at the top right.

The girls point out that the oogtoms move in the direction of the princess, but they are also distributed throughout the screen. In their observations, we see traces of their earlier ideas: namely, that smell goes everywhere and a person breathing in will bring more smell to their nose. In response to the girls’ feedback on their simulation, the facilitators later manipulated Stagecast so that the oogtoms would come out of the orange and "fan out."

The girls also notice that the princess blocks the oogtoms, causing them to move around her. Their observation leads them to consider what happens to smell after you breathe it in. At the start of Day 4, the girls revisit these ideas and talk about how to refine their simulation:

The girls decided that in real life smell gets consumed, so they programmed the oogtoms to disappear when they reach a princess. After these changes, the girls watch what happens and discuss whether their simulation represents what smell does:

The girls are excited to see that the princess consumes the oogtoms. A facilitator suggests moving and adding princesses and the girls observe the amount of smell princesses consume at different locations.

Eileen noticed that her princess was blocking the oogtoms coming out of the orange, which led the girls to question how a princess's distance from the orange would impact the number of oogtoms she consumes.

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