Earth’s Magnetism and Sea Floor Spreading

By:

Jeff Friesen
Jocelyn Delamore
Mike Moffitt

 

The following labs and PowerPoints are intended to supplement lessons that incorporate California Content Standards from both Electricity/Magnetism and Earth Science.  The study of Earth’s dynamics is an intriguing context in which to learn about magnetism and its applications.  After basic introduction to magnetism, students are introduced to compasses and their relation to the Earth’s magnetic field.  This information serves as a necessary foundation for understanding how Sea-Floor Spreading provides strong evidence for the theory of Plate Tectonics. 

 

Lab – Introduction to Magnetic Fields

Lab – Which Way is North?

Lab – Modeling Sea Floor Spreading

PowerPoint – Earth’s Magnetic Field

PowerPoint – Historical Introduction: Continental Drift Theory

PowerPoint – Sea Floor Spreading

 

For additional lesson ideas, activities, or enrichment readings applicable to this unit, refer to the following resources:

w      NOVA video: “Magnetic Storm” 

w      Exploratorium “Science Snacks” on Magnetism

w      Exploratorium WebQuest:  “Auroras: Paintings in the Sky”

 

 

 

California Content Standards

Grade 9-12 Physics: Electric and Magnetic Phenomena

5. Electric and magnetic phenomena are related and have many practical applications. As a basis for understanding this concept:

f. Students know magnetic materials and electric currents (moving electric charges) are sources of magnetic fields and are subject to forces arising from the magnetic fields of other sources.

g. Students know how to determine the direction of a magnetic field produced by a current flowing in a straight wire or in a coil.

i. Students know plasmas, the fourth state of matter, contain ions or free electrons or both and conduct electricity.

Grade 9-12 Earth Science: Dynamic Earth Processes

3. Plate tectonics operating over geologic time has changed the patterns of land, sea, and mountains on Earth's surface. As the basis for understanding this concept:

a. Students know features of the ocean floor (magnetic patterns, age, and sea-floor topography) provide evidence of plate tectonics.

Grade 6 Earth Science: Plate Tectonics and Earth's Structure

1. Plate tectonics accounts for important features of Earth's surface and major geologic events. As a basis for understanding this concept:

a. Students know evidence of plate tectonics is derived from the fit of the continents; the location of earthquakes, volcanoes, and midocean ridges; and the distribution of fossils, rock types, and ancient climatic zones.

b. Students know Earth is composed of several layers: a cold, brittle lithosphere; a hot, convecting mantle; and a dense, metallic core.

Grade 4 Physical Sciences: Electricity and Magnetism

1. Electricity and magnetism are related effects that have many useful applications in everyday life. As a basis for understanding this concept:

b. Students know how to build a simple compass and use it to detect magnetic effects, including Earth's magnetic field.

c. Students know electric currents produce magnetic fields and know how to build a simple electromagnet.

f. Students know that magnets have two poles (north and south) and that like poles repel each other while unlike poles attract each other.