Related Lessons

El Niño

In earlier grades, students learned about the atmosphere, weather, and oceans in a descriptive sense. At this grade level, students should learn how the atmosphere and oceans affect one another, as well as how a small change in sea surface height can have a large impact on weather.

This lesson explores these concepts in the context of El Niño. El Niño is a mass of warm water that moves eastward as trade winds relax. The warm water brings torrential rains to parts of the world that are not prepared for such weather.

This lesson is a good follow-up to the 6-8 Science NetLinks lesson on Oceans.

Materials:

• Small, same sized cups (any material; e.g., ceramic, plastic, styrofoam)
• Hand-held mirrors
• Water
• World map (This will help students when they are trying to figure out the patterns of El Niño. Also, the map will help them locate the land at either side of the Pacific where many El Niño outcomes are located.)
• Print copies of Online Focus: Smoggy Weather from PBS Online

Distribute the first three pages of  Online Focus: Smoggy Weather from PBS Online.

Have four people come to the front of the room to act out the newscast and roundtable forum. Each person will take a role: One person will read Jim Lehrer's lines, another the reporter’s, Mark Austin. After this short newsreport has been read, the other two students will act out the roundtable as Don Henry and Tony Whitten, along with the student playing Jim Lehrer.

Tell the “audience” they may take notes in their journals while listening.

After the newscast, discuss the following questions. You will revisit these at the end of the lesson:

• What are some outcomes of El Niño? (Though people are purposefully burning brush for future crops in Indonesia, an underlying problem is the drought caused by El Niño.)
• What is El Niño?
• What causes El Niño?
• How does El Niño, a mass of warm water in the ocean, have a global impact on weather?

Since students have likely heard about El Niño in the news, they will probably know that it has to do with weather. What they may not know is how activity in the atmosphere and ocean unfold to create an El Niño. In order to get to the root of the cause, students will first approach the subject in a general sense, then take a step back to learn about convection loops and trade winds. They will learn more about outcomes (other than the fire in Indonesia) toward the end of the lesson.

Have students break into small groups and go to Hot Air Over Hot Water from the Frankilin Institute. Have each group read the general information about El Niño and do the simple activity described on the page.

In this activity, students will fill two cups, one with hot water, one with cold, and put their hands over the cups to feel that hot water warms the air above it and cool water doesn't. The second part of the activity, in which they hold the mirror over the hot water cup, shows that warm water below evaporates and rises and accumulates on the mirror in water droplets.

If students still have the last web page open, have them click and read The Science Behind El Niño.

The reading and the activity both make the same point: warm water causes water vapor, which comes back down in the form of rain when it is cooled. However, the reading describes what is different in the case of El Niño.

Ask the following questions:

• What causes storms?
• If water rising from the ocean and falling back down as precipitation is a common occurrence why is El Niño different?
• What causes the water to become warm?

Now students are ready to get into the specifics of El Niño. Have them individually read about tradewinds in El Niño Events from the WW2010 website. Ask students to record how tradewinds effect El Niño in their journals.

Also at WW2010, have students read about Upwelling and Thermocline.

Upwelling is the rising of deeper colder water in the ocean and thermocline is the transition layer between the mixed layer at the surface and the deep water layer. Students should draw diagrams of both of these as well as describe them in their journals.

For a fuller overview of El Niño, students can read the following websites:

• Winter's Weird Weather: What's the Cause? from the Why Files
• Resources on El Niño and La Niña
  

The latter is more detailed than the first, but a reiteration of this complicated information may help students in understanding the process.

As students read the articles, have them create story boards, which give step-by-step explanations of how El Niño happens. They may use the diagrams of upwelling and thermoscline.

Once students are done with their rough story boards, have them meet in groups to compare and discuss their sketches. If needed, they can revisit the articles to clarify any inconsistencies between their drawings. Once the inconsistencies are worked out, each group can create one large poster using ideas from their individual sketches. Each drawing should be labeled.

The final activity is to have each group present their poster, explaining the steps and answering questions from the "audience." These presentations will serve as your assessment of each group's understanding of El Niño. The poster building and presentations also give students a chance to work in teams and practice public speaking. 

After each presentation, students should be encouraged to go back and correct any inaccuracies on their posters. 

If you have time and want to incorporate more writing into the final activity, have students act out the forum once again. Only this time, have students write their own scripts and use their posters as props. Each group should use their poster as a centerpiece, and build a script around the science behind El Niño. Each person in the group should have a part. 

This final activity will mirror the opening motivation activity, only it will be more focused on the science behind El Niño, with only minor references to the outcomes. If students need more material for discussion in their scripts, you can have them explore the following sites (these sites are more outcome related than scientific):

• Atmospheric Consequences of El Niño
• Winter's Weird Weather: What's the Cause?
  
• What is an El Niño?
• OCEAN_PLANET-El Niño

Have each group act out their news forum using the map and diagrams when necessary. You can evaluate their understanding of El Niño by the content of their forums.

El Nino happens once every four to seven years. Have students chart the patterns of El Niño. For a printout activity in which students construct a timeline of El Niño, go to El Niño Task #3 on the Athena website.

For more general information on oceans, explore Oceans Alive from the Museum of Science in Boston. This site covers ocean currents, waves, gravity, and ocean life.

Created :10/05/2000