Magnetism Flashcards
In order for a magnet to be magnetized the domains must be?
Lined up
How to demagnetize a magnet?
- Heating
- Dropping repeatedly
- Other strong impacts
Steps for sea floor spreading
- Ocean floor rock is formed by molten material (melted rock) that seeps through a crack in the ocean floor.
- The magnetic material (iron) in the molten rock lined up in the direction of the earth’s magnetic field.
- When the rock cools, it creates a permanent record of the magnetic field.
Scientists have learned that the _______ and ______ of earth’s magnetic field has changed over time.
Direction and strength
Earth’s magnetic field has completely ______ direction every million years or so.
Reversed
What is the mid ocean ridge?
Winds beneath the earth’s oceans.
What is sea floor spreading?
Theory proposed by Harry Hess
Now material is continually being added to the ocean floor.
What is the deep ocean trench?
Deep, underwater trench
Forms where oceanic crust bends
Subduction takes place here
Evidence for sea floor spreading
Molten material
Magnetic stripes
Drilling samples
What is subduction?
Process by which oceanic crust sinks down beneath trench into mantle
Along what feature of the ocean floor does sea floor spreading begin?
Mid ocean ridges
The angle between a line to the geographic north pole and a line to the north to which a compass points is known as? What does this depend on?
Magnetic Declination
Your location
The region of earth’s magnetic field shaped by the solar wind?
Magnetosphere
The glowing region in the atmosphere caused by charged particles from the sun?
Aurora
Is any material that attracts iron and materials that contain iron?
Magnet
