Contributed by: Council of Chief State School Officers (CCSSO)
Item Description:
The exercise is intended to show the students how a compass can
be affected by placing it near different objects. The students are
given a penny and a bar magnet and asked to place these items, one
at a time, in the center of a shaded rectangle. The compass is to
be placed at five different points around the shaded rectangle.
The students are asked to draw arrows to show the direction the
compass needle is pointing with each object.
A good response will show that the student understands that a
compass needle is magnetic and magnets are attracted to each other,
or that a compass needle is attracted to a magnet but not to all
metal objects.
Question 1 asks the students to interpret the results of their
experiment and explain why either the penny or the magnet caused
the compass to work incorrectly.
A good response will show that the student understands that the
compass should always point north. when the magnet is placed in
the shaded rectangle the compass will point toward the magnet, i.e.,
causing it to work incorrectly.
Question 2 asks the students to further use their understanding
of the effects of a magnet on a compass by asking them to draw arrows
on map showing which way a compass will point when placed by a magnet.
They are asked to explain why they drew the arrows where they did.
A good response will show the student understands that a magnet
attracts the compass needle because the compass is magnetic and
magnet attract. Some but not all metals are attracted to a magnet
as illustrated by the penny.
Summary Table:
Criterion
1 |
Observation:
Magnet with explanation (Q1) (explanation may be very basic
and/or based on observations).
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2 |
Properties of magnet:
Magnet with explanation (Q1) (explanation must go beyond
the observations from the experiment and attempt to explain
why the magnet affects the compass)
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3 |
Arrows drawn in the direction of the magnet or it is explained
that only the closest ones will. (Q2)
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4 |
Explanations include information about how magnets are attracted
to each other or some metal objects are attracted to a magnet.
(Patterns of attraction or repulsion - and variability in
tendency to attract.)
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Rubric
Criterion 1:
(Q1) The student states that the magnet causes the compass
to work incorrectly and an explanation is given. The explanation
may be very basic and may be based on observation. For example:
a) The magnet because the compass didn't always point north.
b) The magnet because every time the compass turned a different
way.
This criterion is also met if the results of the experiment are
misinterpreted. For example:
a) The penny causes it to work incorrectly because the penny will
not attract the compass.
No other reason is acceptable for stating the penny caused the
magnet to work incorrectly. Also, the statement, "The magnet is
really magnet" is unacceptable.
Criterion 2:
(Q1) The student states the magnet causes the compass to
work incorrectly and an explanation is given that shows the student
understands why the magnet affected the compass. The explanation
must go beyond the observations and must discuss properties
of magnets.
- Because the magnet is metal.
- Because there is metal in the compass.
- Magnets are attracted to metals.
- The compass didn't work because of the magnetic force around
the magnet.
- Compass always points north unless another magnet interferes.
(Note: If this response had been, "unless a magnet interferes,"
it would have met criterion 1 but not criterion 2. By stating
"another magnet," the student recognizes that a compass is magnetic
which goes beyond observations made in the experiment.)
*All responses that meet criterion 2 automatically
meet criterion 1.
Criterion 3:
(Q2) Arrows are drawn from al four circles in the direction consistent
with the placement of each circle. This criterion is met if:
- arrows from circle #1 (top of figure), #2 (left of figure),
and #3 (right of figure) point toward the top of the page (the
magnet in the figure has its north pole indicated at the top);
and
- the arrow from circle #4 (bottom of figure) points toward the
bottom of the page because the north indicator end of the compass
needle (i.e., its south pole) is repelled by the magnet's south
pole.
Criterion 4:
The explanation given in question 1 or in question 2, shows the
student understands that magnets are attracted to each other (the
compass is magnetic, or not all metal objects are attracted to a
magnet, i.e. why the magnet and not a penny affects a compass.
For example:
- A magnet is attracted to some metal objects.
- Compasses always point north unless another magnet interferes.
- The magnet because a compass is magnetic.
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