PY 131 exam 1 Questions and Answers Already Passed Latest Update 2025-2026
Consider the model from a different group, similar to but not the same as Group 2's model: (one
unmagnetized and one South Pole left and North Pole right/tip of nail) s[___}>n
Description: There are no magnetic entities associated with the unmagnetized nail, but when a
magnet is rubbed along the surface of the nail, it deposits small N and S entities (like dust
particles) loosely along the surface, as shown.
Which of the following observations made by some other groups would be difficult to explain
(or could not be explained) using this model? - Answers Cutting the nail anywhere along its
length produces two pieces that each behave like two-ended magnets., When cut in half, each
end of each half of the nail (four ends in all) can pick up the same number of paper clips. ,
After dropping the magnetized nail in water and removing it, the wet nail is still magnetized.`
Now consider a group who found that, when they cut a magnetized nail into either halves or ¼
and ¾ pieces, the pieces of the magnetized nail still behaved as if they were two-ended.
mixed (south and north poles)
Description: Inside the nail, there are equal numbers of separate N and S magnetic particles that
can move around when attracted or repelled by a magnet. In the unmagnetized nail, they are all
jumbled up randomly. When the nail is rubbed with one pole of a bar magnet, the magnetic
particles arrange themselves as shown in the diagram.
Which of the following observations made by some other groups would be difficult to explain
using this model? - Answers Cutting the nail anywhere along its length produces two pieces that
each behave like two-ended magnets.
This group's model is similar to the last group's model. In this case, the group performed
experiments in which they cut a number of magnetized nails into two pieces of various lengths
and found that both pieces were always two-ended. Here is their model for the magnetized nail:
Description: Inside the nail there are equal numbers of separate N and S magnetic particles that
can move around when attracted or repelled by a magnet. In the unmagnetized nail, these N and
S particles are all jumbled up randomly. When the nail is rubbed with one pole of a bar magnet,
the magnetic particles arrange themselves alternately along the length of the nail.
Could this model be used to explain the observation that when a magnetized nail is cut into two
pieces of arbitrary lengths both pieces are always two-ended? - Answers No, according to the
, diagram, there are some places where the nail could be cut and the two pieces produced would
not be two-ended.
Here are four possible things that could be done to any object.
I. Hit it with another hard object.
II. Heat it to a very high temperature.
III. Cool it to a very low temperature.
IV. Bring it close to one end of a permanent magnet.
Considering all the evidence you have seen in this unit, in terms of the alignment of domains
model, which of these seem to be able to change the orientation of at least some of the
domains in a ferromagnetic object? - Answers I , II and IV.
A group of students constructed the following explanation for why the N-pole of compass
needle rotated toward the tip of a magnetized nail placed at the E-label, but after the nail was
heated the needle showed no reaction.
(1) Before it is heated all the S-poles of the domains in the magnetized nail are facing the tip of
the nail, making it a S-pole that attracts the N-pole of the compass needle. (2) When the nail is
heated the domains get jumbled up with no preferred direction of alignment. This means the tip
of the nail is now unmagnetized and the tip is longer any particular pole. (3) Since there is an
attraction between an unmagnetized object and both poles of a magnet, both ends of the
compass needle are now attracted to the nail. These two attractions tend to make the needle
rotate in opposite directions, so they cancel each other out and the needle does not move.
What is your evaluation of this explanation i - Answers It is not well-constructed because the
diagram and narrative are inconsistent.
Now consider only the narrative from the same explanation.
(1) Before it is heated all the S-poles of the domains in the magnetized nail are facing the tip of
the nail, making it a S-pole that attracts the N-pole of the compass needle. (2) When the nail is
heated the domains get jumbled up with no preferred direction of alignment. This means the tip
Consider the model from a different group, similar to but not the same as Group 2's model: (one
unmagnetized and one South Pole left and North Pole right/tip of nail) s[___}>n
Description: There are no magnetic entities associated with the unmagnetized nail, but when a
magnet is rubbed along the surface of the nail, it deposits small N and S entities (like dust
particles) loosely along the surface, as shown.
Which of the following observations made by some other groups would be difficult to explain
(or could not be explained) using this model? - Answers Cutting the nail anywhere along its
length produces two pieces that each behave like two-ended magnets., When cut in half, each
end of each half of the nail (four ends in all) can pick up the same number of paper clips. ,
After dropping the magnetized nail in water and removing it, the wet nail is still magnetized.`
Now consider a group who found that, when they cut a magnetized nail into either halves or ¼
and ¾ pieces, the pieces of the magnetized nail still behaved as if they were two-ended.
mixed (south and north poles)
Description: Inside the nail, there are equal numbers of separate N and S magnetic particles that
can move around when attracted or repelled by a magnet. In the unmagnetized nail, they are all
jumbled up randomly. When the nail is rubbed with one pole of a bar magnet, the magnetic
particles arrange themselves as shown in the diagram.
Which of the following observations made by some other groups would be difficult to explain
using this model? - Answers Cutting the nail anywhere along its length produces two pieces that
each behave like two-ended magnets.
This group's model is similar to the last group's model. In this case, the group performed
experiments in which they cut a number of magnetized nails into two pieces of various lengths
and found that both pieces were always two-ended. Here is their model for the magnetized nail:
Description: Inside the nail there are equal numbers of separate N and S magnetic particles that
can move around when attracted or repelled by a magnet. In the unmagnetized nail, these N and
S particles are all jumbled up randomly. When the nail is rubbed with one pole of a bar magnet,
the magnetic particles arrange themselves alternately along the length of the nail.
Could this model be used to explain the observation that when a magnetized nail is cut into two
pieces of arbitrary lengths both pieces are always two-ended? - Answers No, according to the
, diagram, there are some places where the nail could be cut and the two pieces produced would
not be two-ended.
Here are four possible things that could be done to any object.
I. Hit it with another hard object.
II. Heat it to a very high temperature.
III. Cool it to a very low temperature.
IV. Bring it close to one end of a permanent magnet.
Considering all the evidence you have seen in this unit, in terms of the alignment of domains
model, which of these seem to be able to change the orientation of at least some of the
domains in a ferromagnetic object? - Answers I , II and IV.
A group of students constructed the following explanation for why the N-pole of compass
needle rotated toward the tip of a magnetized nail placed at the E-label, but after the nail was
heated the needle showed no reaction.
(1) Before it is heated all the S-poles of the domains in the magnetized nail are facing the tip of
the nail, making it a S-pole that attracts the N-pole of the compass needle. (2) When the nail is
heated the domains get jumbled up with no preferred direction of alignment. This means the tip
of the nail is now unmagnetized and the tip is longer any particular pole. (3) Since there is an
attraction between an unmagnetized object and both poles of a magnet, both ends of the
compass needle are now attracted to the nail. These two attractions tend to make the needle
rotate in opposite directions, so they cancel each other out and the needle does not move.
What is your evaluation of this explanation i - Answers It is not well-constructed because the
diagram and narrative are inconsistent.
Now consider only the narrative from the same explanation.
(1) Before it is heated all the S-poles of the domains in the magnetized nail are facing the tip of
the nail, making it a S-pole that attracts the N-pole of the compass needle. (2) When the nail is
heated the domains get jumbled up with no preferred direction of alignment. This means the tip
