<img src="https://d5nxst8fruw4z.cloudfront.net/atrk.gif?account=iA1Pi1a8Dy00ym" style="display:none" height="1" width="1" alt="" />
Dismiss
Skip Navigation

2.2: Earth's Magnetic Field

Difficulty Level: Basic Created by: CK-12
Atoms Practice
Estimated4 minsto complete
%
Progress
Practice Earth's Magnetic Field
 
 
 
MEMORY METER
This indicates how strong in your memory this concept is
Practice
Progress
Estimated4 minsto complete
%
Estimated4 minsto complete
%
Practice Now
MEMORY METER
This indicates how strong in your memory this concept is
Turn In

How can you find your way?

You can use Earth's magnetic field to tell you where you want to go. A compass needle aligns with Earth’s magnetic field. People can navigate by finding magnetic north. If you know where north is, you can figure out how to get anywhere. A compass is great for finding your way when you're out in the field!

Earth’s Magnetism

Earth has a magnetic field (Figure below). The magnetic field behaves like a giant bar magnet inside Earth. If you have a large bar magnet, you can hang it from a string. Then watch as it aligns itself in a north-south direction. It does this to line up with Earth’s magnetic field.

Earth's magnetic field is like a bar magnet that resides in the center of the planet.

The magnetic field has north and south poles. The magnetic poles do not exactly match the geographic poles. So the magnetic north pole is not the same as the geographic north pole. The same is true of the south pole. The magnetic field is created by the movement of molten metal in the outer core.

Earth’s magnetic field extends several thousand kilometers into space. It shields us from harmful radiation from the Sun (Figure below).

Earth's magnetic field protects the planet from harmful radiation.

Magnetic Reversals

Something very strange has happened many times during Earth history. The planet's magnetic field flipped! The north pole became the south pole. The south pole became the north pole. Scientists are not sure why this happens. The fact that it does happen is useful to scientists. In Concept Plate Tectonics, you'll learn how.

Vocabulary

  • magnetic field: A field produced by a magnetic object. The object exerts a force on other magnetic materials or moving electrical charges.

Summary

  • Earth's magnetic field is like a bar magnet through the planet.
  • The magnetic field is generated by convection in the liquid outer core.
  • Occasionally the magnetic field flips. The north pole becomes the south pole and the south pole becomes the north pole.

Interactive Practice

Use this resource to answer the questions that follow.

  1. What aligns itself with the magnetic field in molten rocks as they cool?
  2. What did Brunhes' discover about some of the rocks?
  3. What did Brunhes' discovery mean?
  4. What has happened to the magnetic field in the last century?
  5. What planet is being studied to discover the future of Earth without a magnetic field?

Review

  1. Why does Earth have a magnetic field?
  2. Why is it important for Earth to have a magnetic field?
  3. What is a magnetic reversal?

    Notes/Highlights Having trouble? Report an issue.

    Color Highlighted Text Notes
    Please to create your own Highlights / Notes
    Show More

    Vocabulary

    magnetic field

    Field produced by a magnetic object. The object exerts a force on other magnetic materials or moving electrical charges.

    Image Attributions

    Show Hide Details
    Description
    Difficulty Level:
    Basic
    Grades:
    6 , 7
    Date Created:
    Jan 04, 2013
    Last Modified:
    Aug 31, 2016
    Files can only be attached to the latest version of Modality
    Please wait...
    Please wait...
    Image Detail
    Sizes: Medium | Original
     
    SCI.ESC.300.2.L.2
    Here
    Add Note
    Please to create your own Highlights / Notes