What Do You Smell?


  • Use creative imagery and writing to think about the effects of air pollution.
  • Observe how air pollution can move from one region to another.


  • Orange or onion (or other similar pungent odor-producing item)
  • Optional electric fan, if air movement in your classroom is insufficient to circulate the odor


  1. Have students close their eyes or turn their backs as you peel the orange/onion and allow the odor to "travel" throughout the classroom. Ask students to raise their hands as soon as they smell the orange/onion.
  2. Plot the sequence of "smellings" on a room chart, noting the approximate time when the first and last students smell the orange. Patterns may not be simple "nearest to most distant," and will show how air circulates through the classroom. You could change the results by placing the cut orange/onion near an air vent or in some other part of the room.
  3. For older students, this experiment could be conducted prior to lunch or a brief recess. When the class leaves the room, take the orange or other odor source from the room also. Have some students return to the room at 5 or 10-minute intervals to see whether they can still smell the odor. When class returns, discuss what the students observed.
  4. What does that indicate about how long it takes for the classroom air to be fully replaced?
  5. What do students conclude about the effect of wind on air pollution?
  6. Have students describe how they think the air smells in different places, such as a bike trail, a busy highway, children at school, garbage burning, a backyard lawn mower, barbecue or the beach?
  7. Have students write about what they imagined.