Magnetic Reversals: Fact and Fiction.

Introduction:

A recent 2003 movie 'The Core' proposes that if Earth were to temporarily lose its magnetic field, a wide range of deadly calamities would befall humans and living creatures on Earth.

What will really happen?

Students may have difficulty separating fact from fiction, especially when modern-day science fiction movies seem so believable, and actors have become really good at 'talking science'.

Here's what CBS News said about The Core in a short synopsis:

"In "The Core," the Earth's inner core has stopped rotating, causing the planet's electromagnetic field to rapidly deteriorate. This can cause airplanes to start falling from the sky and everything electronic to be destroyed. And static discharge in the atmosphere threatens to create "super storms." Plus microwave radiation will literally cook the planet."

What you should note is the sloppy use of terminology, and the subtle introduction of many 'facts' about what might actually happen as though they are certifiably sound, scientifically. In fact, there is not a single idea in the above paragraph that makes sense.

Luckily, we don't have to speculate about what might happen. Over 400 magnetic reversals have been detected by geologists dating back to nearly 330 million years ago. By studying them carefully, scientists are learning about their impacts to Earth.

This activity will help students discriminate between factual and fictional descriptions of a natural phenomenon, which has been scientifically studied from the fossil and geologic record of Earth, and found to be a lot less frightening than Hollywood (or CBS News!) would have us imagine!

 

Objective:

Students will read to be informed. They will learn about Earth's magnetic reversals by reading two fiction stories and a scientific summary of past reversals, including graphical information.

Materials:

 Story 1...."Holocaust"

 Story 2...."The Turning Point"

 Story 3..."Magnetic Reversals: Back to the Future?"

 Vocabulary Transparency Master

 

Vocabulary:

 Magnetic Intensity

 Magnetic Polarity

 Magnetic Reversal

 Magnetic Field

 Electromagnetic Field

 Ionosphere

 Aurora

 Plasma

 Microwave

Procedures:

  1. Review the basic vocabulary.
  2. From the introductory material, discuss Earth's magnetic field and what the students may have heard about its changes over time, and their impacts on life on Earth.
  3. Provide time to allow the students to complete the reading assignment and answer the accompanying questions.
  4. Review the answers. Construct a Venn Diagram for the three stories which identifies the predictions by each story and finds their common elements.
  5. Discuss with the students how unsteady Earth's magnetic field has been, and how only the most extreme variation 730,000 years ago actually led to a complete magnetic reversal. You may wish to review the previous activity: Magnetic Reversals and Variation
  6. Discuss the basic science concepts presented by the two science fiction stories, and the discussion by an astronomer.