To understand that El Niño is caused by changes in the atmospheric and ocean content.
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.
Distribute copies of El Niño, from PBS Newshour.
Ask six students come to the front of the room to act out the newscast. Each person will take a role:
- Antonio Neves
- Voice Over
- Mike Halpert
- Ning Zeng
- Tom Jordan
- Denise Breitburg
Tell the “audience” they may take notes in their journals while listening.
After the newscast, discuss these questions. You will revisit them at the end of the lesson:
- What are some outcomes of 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?
- (Though people are purposefully burning brush for future crops in Indonesia, an underlying problem is the drought caused by El Niño.)
- (El Niño is a part of the regular cycle of ocean temperatures across the Pacific Ocean. It is a band of warm ocean water that develops in the equatorial Pacific.)
- (It is still unclear what causes the change in ocean temperatures.)
- (It can cause drought in some areas of the world, like Indonesia, Borneo, Papua New Guinea, and the eastern coast of Australia. While in other areas of the world, it can bring heavy rainfall and floods, like in Peru. Heavier rainfall in areas like the Chesapeake Bay can lead to an explosion in the growth of algae, which can create dead zones iin the bay.)
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.
Divide students into small groups. They should use their El Niño student esheet and go to What is El Niño? from the National Oceanographic and Atmospherica Administration. Each group should read the general information about El Niño. Once they have read that page, each group should do the simple activity described on their El Niño student sheet.
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.
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.
Students should then answer these questions on their El Niño student sheet:
- 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. They should use their esheet to individually read about tradewinds in El Niño Events from the WW2010 website. Ask students to record how tradewinds affect El Niño on their student sheet.
Also at WW2010, students should 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 on their student sheet.
For a fuller overview of El Niño, students can read these websites:
As students read the articles, they should create story boards, which give step-by-step explanations of how El Niño happens. They may use the diagrams of upwelling and thermoscline. They can follow the directions on the El Niño Storyboard student sheet.
Once students are done with their rough story boards, they should 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, students can act out the forum once again. Only this time, students should 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, they can explore these sites (these sites are more outcome related than scientific):
Each group should 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.
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.