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Earth’s Forces
Based on Discover God’s Creation, chapter 2-4
By Rebecca Fraker
Gravity
• Gravity can be defined as the
pull of matter on matter.
• The force of gravity keeps you on
the earth.
• But gravity also acts between any
two objects.
More about gravity
• The gravity of a planet or moon depends
on the amount of matter it contains, or its
mass.
• The moon, with one-sixth the mass of the
Earth, has one-sixth the Earth’s gravity.
• Weight is the measure of the pull of gravity
on an object NOT the amount of material in
the object. So you would weigh less on the
moon—but still be the same size.
Magnetism
• Another force of
attraction that affects
Earth is magnetism.
• Like a bar magnet, the
earth has a magnetic
north and south pole.
• These magnetic poles
are not at the same
location as the
geographic North and
South poles.
Magnetosphere
• Like a magnet, the earth has a
magnetic field surrounding it. This
is called the magnetosphere.
• This magnetic field deflects some of
the sun’s dangerous radiation.
• For centuries, people have used
Earth’s magnetism to navigate by
the aid of a compass.
• Many animals also have the Godgiven ability to use earth’s magnetic
field for navigation in their yearly
migrations.
Migration uses magnetism
• There have been changes discovered in
both gravity and the earth’s magnetic field.