Water Cycle - Atmosphere (6)

  • Tracing atmospheric winds.
  • Exploring how particles move in the atmosphere.
  • ash
  • Coriolis Effect
  • disaster
  • nuclear
  • ash distribution map of Mt. St. Helens
  • world map

Students determine the effect of nuclear disaster in the atmosphere.


The rotation of the Earth affects the movement of the atmosphere.  The Coriolis motion plays a similar role in the atmosphere as it does in the oceans.  Air is much more fluid than water and can move more rapidly.  The atmosphere also has different factors affecting it, such as temperature differences, topography, and location (i.e., over land or water). A basic cause of wind  movement in the atmosphere is the difference of temperature.  Warm  air rises, which causes movement. Air can move horizontally from high to low  pressure areas.  Moving air already in motion is deflected by the Coriolis Effect.  The Coriolis Effect deflects particles in the northern hemisphere to the right, and to the left in the southern hemisphere. These three basic factors, Coriolis motion, pressure differences, and differences in temperature, create the patterns that are shown in the students' lab sheet, “World Wide Air Movement.”  

We can learn about the movement of particles in the atmosphere, especially the troposphere (about 0-17 km) and the stratosphere (about 17-48 km) by charting particle movements.  Sometimes a natural event, like a volcano explosion can help determine the wind patterns.  Mt. St. Helens is a volcano that violently erupted in 1980. Ash from the explosion was transported to very far distances.   Maps of the direction of movements provided valuable information on the wind patterns in the troposphere and stratosphere.   Collecting data from one event and then using that data to predict the outcome of another event is an experimental tool in science.  Meteorologists use this type of data collection to help them predict future events.

  1. Look at the Mt. St. Helen’s maps and answer the appropriate questions on the lab sheet.  Go over the distribution maps with the students before they answer the questions. Can the ash flow be connected with wind direction? Get the students to compare the different maps. The air currents played a direct role in transporting ash over thousands of miles.  Ash from volcanoes can be helpful and harmful.  The ash contains minerals that when incorporated in soil, increases plant growth.  However, the fine particles can get into lungs and cause respiratory damage. 
  2. After the students look at the Mt. St. Helens and air flow maps, have them trace the direction that fallout from a "Nuclear" disaster would travel.  The knowledge they learned about the volcano eruption should help them predict what would happen during an event that would become airborne. Talk about the importance of the atmosphere and how it moves fine-grained particles.  Students need to carefully look at the direction of the wind patterns.  You may want to add other locations on the map. 
  3. Students need to look at the ash data and then make an inference of what might happen in a separate event.  Students should think about whether nuclear fallout is similar to ash.  Some of the students may even ask what type of nuclear disaster.  Do you mean a warhead or a nuclear plant that fails?  Encourage your students to look at the similarities, but also the differences.   Understanding the two models can help make a more accurate prediction.  This might lead into a discussion about effects of nuclear war or other pollution that can be carried by the atmosphere.  So be prepared!

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