Up to 32 students

Two 45-60 minute sessions


El Nino is an abnormal warming of surface ocean waters in the eastern tropical Pacific and is one part of what's known as the Southern Oscillation. The Southern Oscillation is the see-saw pattern of reversing surface air pressure between the eastern and western tropical Pacific. Periodically when the surface pressure is high in the eastern tropical Pacific it is low in the western tropical Pacific, and vice-versa, this phenomena occurs. Because the ocean warming and pressure reversals are relatively simultaneous, scientists call this phenomenon the El Nino/Southern Oscillation or ENSO for short. South American fisherman have given this phenomenon the name El Nino, which is Spanish for "The Christ Child," because it comes about the time of the celebration of the birth of the Christ Child-Christmas.

El Nino Conditions

Scientists do not really understand how El Nino forms. It is believed that El Nino may have contributed to the 1993 Mississippi and 1995 California floods, drought conditions in South America, Africa and Australia. It is also believed that El Nino contributed to the lack of serious storms such as hurricanes in the North Atlantic which spared states like Florida from serious storm related damage. Therefore a change in one aspect of one pceans oscillation can have global effects.

Unfortunately not all El Nino's are the same nor does the atmosphere always react in the same way from one El Nino to another. This is why NASA's Earth scientists continue to take part in international efforts to understand El Nino events. Hopefully one day scientists will be able to provide sufficient warning so that we can be better prepared to deal with the damages and changes that El Nino causes in the weather.

Learning Objectives:

1. To become familiar with terms such as oscillation, El Nino and their global effects.

Guiding Questions:

What is El Nino? Why does a change in the Pacific have global effects? How often do El Nino events happen?



Internet connection

Class Discussion on Surface warming and slow down of southern oscillation.

Activity 1:Think, Pair, Share

Print out or have students read aloud the article from NASA below:

El Nino Article

And discuss the article and what they were able to take from it.

Activity 2: Online Investigations:

Give a list of questions for student to investigate such as:

How often does El Nino occur?

What are some weather/climate effects of El Nino?

Are there economic effects from El Nino Events?

Suggested websites:


NOAA - El Nino

University of Illinois

Franklin Institute

Florida State University


Conclusion and Wrap Up:

Discuss as a class the questions that the students were asked to research.

Have students add to their LINK.

Vocabulary to note:


El Nino

New York Scope and Sequence:

Intermediate and High School Science Standards

Physical Setting:

Key Idea 1.2g, 2.1a - 2.1i, 2.1o - 2.1w, 2.2a - 2.2c

Living Environment:

Key Idea 1.1a - 1.1f

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