PROBLEM: How far can ash, airborne pollutants, or other small particles travel?

PREDICTION:

EXERCISE I.
MATERIALS: Ash distribution map of Mt. St. Helens

PROCEDURE: Look at the map and answer the following questions:

1. What happened to the volcanic ash that erupted from Mt. St. Helens? 
     
2. Where was the most ash deposited?
     
3. Why was more ash deposited onto one side?
     
4. Is volcanic ash always harmful? 
   Explain:
   
5. Did any of the Mt. St. Helens ash get blown to the San Francisco Bay
   
   Area? (Why/why not?)

EXERCISE II. 
MATERIALS: Map of world air currents, blank map of the world

PROCEDURE: On your map there is a sad face. This represents the site of a make-believe nuclear disaster. Harmful particles were released into the air. Using the map of world wide air currents, determine which cities or countries were affected most by this disaster. Explain why you chose these cities.

CONCLUSIONS: Locations affected most.