Transcript File - Mrs.Chenu`s Flipped Classroom

Electricity and Magnetism
Investigation 1 part 4:
Detecting Magnetic
Fields
Magnetic Characteristics
 Magnets only stick to iron.
 Two magnets can attract or repel, depending
on the orientation of the north and south
poles.
 A force is a push or a pull.
 The magnetic force acts through space and
most materials.
 The greater the distance between two
magnets, the weaker the force of attraction.
Make a Hanging Magnet
 What do you think will happen if you tie a
string to a magnet and let it hang freely?
 Getters: Two doughnut magnets, two 30 cm
strings.
 Observe hanging magnets…what do you see?
 Insert a 6cm long piece of scratch paper
thorough magnet hole and observe what
happens.
Investigate Poles
 We know these magnets have poles on their
flat sides, a north pole and a south pole. The
magnets are all aligned with one of their
poles pointing toward this wall. My question
is:
 Are all the poles pointed toward this wall the
same pole? In other words, are they all north
or south poles? How could you find out for
sure?
Compass
 What you have made is a compass. A
compass is a permanent magnet that is free
to rotate. Earth is a giant magnet. It has a
magnetic field that surrounds the whole
planet. Earth has a north magnetic pole and
a south magnetic pole. Compasses orient
themselves so that their north pole points
toward the Earth’s North Pole. That’s why
they are useful for orientation on our planet.
 Which direction is north? How do you know?
Compass Exploration
 Getters: one
compass for your
group.
 Explore the behavior
of your compass
when you move it
around a magnet.
Magnet-Detection Challenge
 Can you figure out where two magnets
are taped in a box without looking
inside?
 What are some materials that might be
magnet detectors?
Magnetic Interactions
 Why do you think the filings work like
this?
 Do you think the compass has iron in it?
Why do you think so?
 How did the compass help you locate
the magnet in the box?
 How did you use the information you
collected with the compass?
DECTECTING MAGNETS
 Swap boxes with other
groups.
 The boxes cannot be opened
at any time.
 After completing the
detecting on one box, swap
with another group.
Continue until you have
detected the magnets in four
different boxes.
 After recording the location
of magnets in four boxes,
answer the two questions on
the sheet.
Instructions for Magnet Boxes
 Each group will work in teams of two, using: the box with
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their group’s number on it, two magnets, masking tape.
One pair of student will open the box and tape two
magnets inside without letting the other pair see where
the magnets are.
The other team will use the detecting devices to find the
magnets.
No drawing on the boxes!!! Recording will be done on
paper.
Swap roles. The other team will assemble a new
arrangement of two magnets in the boxes. BE CAREFUL
TO REMOVE TAPE CAREFULLY SO THE BOXES ARE NOT
DAMAGED!
Compass
 A compass is a
magnet used to tell
directions on Earth
Detector
 A detector is
something you use
to gather evidence
about something
you can’t see.
Content Review
 What is a compass?
 A compass is a magnet used to detect Earth’s
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magnetic field.
How can you make a compass?
Hang a magnet so it is free to rotate in response to
Earth’s magnetic field.
Since you can’t see the force of a magnet, how can
you tell there is one present?
Compasses, iron fillings, and iron objects can be used
to detect a magnetic field.
Content Review
 How can you use iron fillings to tell if the object in a
box is a magnet or a steel washer?
 A magnet will attract iron fillings, and a steel washer
will not.
 How can you use a compass to tell if the object in
the box is a magnet or a steel washer?
 If it is a magnet in the the box, one end of the
compass needle will always seek one side of the
magnet, and the other end of the needle will always
seek the other side of the magnet.