Contributed by:
Magnets and magnetism, Magnetic field lines, Magnetic field around the Earth
1.
DO NOW MONDAY
• Find your new assigned seat.
• Write one thing (or more) that you enjoyed
most about your Christmas break.
2.
• Today’s PLAN
– To be prepared for second semester in 7th
Grade Science
– To illustrate Mastery on first semester 7th
Grade Learning Targets
• Today’s DO
– We will review CLASS EXPECTATIONS
– We will look at and retake semester test (if
necessary) and/or do enrichment over first
semester learning targets
– We will prepare our binders for second
semester
3.
CLASS EXPECTATIONS
1) Be on time.
2) Be prepared for class before class
begins.
3) Sit down and begin work on your DO
NOW as soon as you enter the
classroom.
4) Speak ONLY when given permission.
5) Get up out of your seat ONLY when
given permission.
4.
Enrichment Directions
• Go to my teacher website from the BCMS
homepage.
• Click on the Magnetism and Electricity Online
Games Folder.
• Click on each link in that folder and complete the
activities one at a time, STARTING AT THE
BOTTOM (videos). The information in the videos
and jeopardy games that you learn will help you
with the other games at the top of the list.
6.
What are magnets?
• Let’s first start off with what causes an
magnetic field…
• A magnetic field is created around any
moving charged object.
7.
• Magnetism is
the force of
attraction or
repulsion
between
magnetic poles.
8.
What is charged that is moving
within an atom?
• Electrons (e-)
• The atoms within most
materials have paired up
electrons spinning in
opposite directions so
the magnetic field that is
created by one is
cancelled out by the
other.
9.
• Some materials like
iron, nickel, and
colbalt have a
single electron or
pair of electrons
that spin in the
same direction
creating a magnetic
field or a small
atomic magnet.
10.
The atomic sized magnets line up to create
domains within the material.
The individual domains line up to form a magnet.
11.
A magnet has two ends called poles
(dipoles), where the magnetic force is the
strongest.
• No matter how
many times a
magnet is broken,
each piece always
has a north pole
and a south pole.
• There is no such
thing as a
monopole.
12.
A magnetic field exists around a magnet or
any moving charged object.
Magnetic fields are like electric fields or
gravitational fields in that they allow
magnets to interact without touching.
13.
Rules for drawing magnetic field lines
(same as an electric field):
1. Magnetic field lines always go from the north pole to the
south pole (outside a magnet).
14.
Rules for drawing magnetic field lines:
2. Magnetic field lines are closed loops and never cross
or intersect.
15.
Rules for drawing magnetic field lines:
3. Where the magnetic field lines are closer the magnetic
field is stronger.
16.
Draw magnetic flux lines around
the magnets below:
S N
17.
Magnetic Field around the Earth
18.
What we do know…
The north magnetic pole and the geographic North
Pole do not coincide. The magnetic pole is about 1500 km
(930 mi) south of the geographic North Pole and it wanders.
A compass actually indicates the direction of magnetic north,
not true north. Therefore a navigator must need to know the
magnetic declination for a specific area. This is the angular
difference between magnetic and true north.
The details and mechanisms of
how and why the Earth has a
magnetic field are unclear.
They do believe that it may
have something to do with
motions in the liquid outer core.
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