Magnetic reversal sci 10

1. EARTH SCIENCE:
Magnetic
Reversal
Sir Dennis Ar N. Espiritu
10th Grade

2. LEARNING OBJECTIVES:
a. Explain what is magnetic reversal; and
b. Describe magnetic reversal as an
evidence of Seafloor Spreading Theory.

3. Magnetic Reversal
01
What is magnetic reversal?

4. Definitions of
Magnetic Reversal
● The process by which the North pole is
transformed into a South pole and the
South pole becomes a North pole.
● It is mainly generated in the very hot
molten core of the planet and has
probably existed throughout most of the
Earth's lifetime.
● Reverse of a dipole magnetic field.

5. Definitions of
Magnetic Reversal
● Also, called Magnetic Pole Reversals, or
Magnetic “Flip”.
● Moreover, it happens two poles (dipole)
switch places. #

6. HOW DOES THIS LOOK LIKE?
The last magnetic reversal happened between 772,000 and 774,000
years ago.

7. DURING MAGNETIC
REVERSAL:

8. About 1000 years
100 times in the
past 20
millions years
It takes for a magnetic
reversal to complete in
Each time it flips— up to
DID YOU KNOW?
Reversal occurs
4 or 5 times per
million years

9. The Cause
02
What causes magnetic reversal?

10. The poles of magnetic field
reverses due to the change
in the direction of flow in
the outer core.
Why is there a
magnetic reversal ?
How is this possible?

11. When lava solidifies, iron
bearing minerals crystallize.
As these crystallize, the
minerals behave like tiny
compasses align with the
Earth’s magnetic field.

12. The Location
03
Where can we find these magnetic rocks?

13. The occurrence of magnetic
reversals can be explained
through the magnetic
patterns in magnetic rocks,
especially those found in the
ocean floor. This is where we
can find these magnetic rocks,
in ridges, coming from the
outer core of the earth.

14. One famous example is the Mid-Atlantic Ridge found between
South America and Africa.

15. An Evidence
04
Magnetic reversal as an evidence to
Seafloor Spreading Theory

16. Since this change in
polarity occurs, it allows
scientists to visualize
magnetic stripes in the
ocean floor and construct
a magnetic polarity time
scale.
Magnetic Polarity
Time Scale

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