Magnetic EarthChapter 1 Section 3

Pages 22- 27

Objective: Understand the Earth’s magnetic field andCompare magnetic and geographic poles.

Compass: a device that has a magnetized needle that spins freely.

Sir William Gilbert’s Theory: Earth has an immense magnetic field surrounding it, just as there is a magnetic field around a bar magnet.

*Sir Gilbert was the first scientist to offer a theoryof why compasses always point north.

Earth’s magnetism is due to the circulation of molten metal (Iron and Nickel) within the Earth’score.

Compasses point north because their magnetizedneedles align with Earth’s magnetic field.

Draw a line between you and the geographic northpole. Now draw a line between you and the magnetic north pole. The angle you create is calledmagnetic Declination.

*Magnetic Declination differs depending on whereyou are

Since Earth produces a strong magnetic field, Earth itself can make magnets out of ferromagnetic materials.

Earth’s magnetic field affects the movements ofelectrically charged particles in space. Chargedparticles also affect Earth’s magnetic field.

Van Allen Belts: Two doughnut shaped regions that contain electrons & protons traveling at very high speeds

Solar Wind: A stream of electrically charged particles flowing at high speeds from the sun

Magnetosphere: The region of Earth’s magnetic fieldshaped by the solar wind. The solar wind constantlyreshapes the magnetosphere as Earth rotates.

Aurora: A glowing region in the atmosphere caused by charged particles from the sun.

Aurora Borealis = Northern Lights

*an aurora in the Northern Hemisphere

Aurora Australis = Southern Lights

*an aurora in the Southern Hemisphere