Human Air Pollution Detectors

Before the meeting: 

1. Cut up the onion, and tightly seal it in a plastic bag. 

During the meeting: 

1. Space individual Cub Scouts evenly around the room. Tell them that they will be “indoor air pollution monitoring instruments.”   
2. Place a fan in the front of the room and turn it on. Show Cub Scouts the bag with the onion in it. 
3. Ask the “monitoring instruments” to close their eyes tightly and use only their sense of smell for this activity. They need to keep their eyes closed until you tell them to open them. 
4. Tell Cub Scouts to raise their hands as soon as they detect onion smell “pollution” and to leave their hands up as long as they continue to smell it. 
5. In front of the fan, open the bag with the cut onion.  
6. Use a stopwatch or watch with a second hand to time how long it takes for all of the “monitoring instruments” to detect the “pollution.”  
7. Allow the fan to continue to run.  Record how long it took for indoor air pollution to spread through the room.  
8. Close and seal the bag as soon as each child has detected the “pollution”. Place the bag in a drawer or outside.   
9. If possible, open a window and place the fan so that it is blowing in fresh air from outside. 
10. Restart the stopwatch.  
11. Ask the “monitoring instruments” to lower their hands when they can no longer smell the onion “pollution”. 
12. Record how long it takes for fresh air to sweep the “pollution” from the room.  
13. Have the children open their eyes.  
14. Discuss how long it took for everyone to detect the “pollution,” and how it took for it to go away.