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Re: [Phys-l] [ncnaapt] New Physics CST Questions Released!



Hi Dean,

I think it is great that you are asking for critical feedback on the new
questions on the California Standards Test some of which are available
at
http://phyzblog.blogspot.com/2007/02/cst-questions-released.html .
It seems likely that such efforts will result in a higher quality test
in the future. Kudos! Here's my opinion on some of the newly released
questions:

1. The answer is a matter of opinion. Folks who are well-versed in
interpreting graphs, would prefer to view the angle vs. range graph but
folks who have trouble with graphs would probably find it easier to
interpret the table of values that would duplicate the given table of
values if it were entered into a spreadsheet or database that displayed
the table of values. I think that a question whose answer is a matter
of opinion should be left off of a standards test. I think it would be
better to display a graph of the data, or a best fit curve to the data
and ask the test taker to interpret the graph. You might ask whether a
launch at an angle five degrees greater than the launch angle that
yields maximum range would come closer to yielding a maximum range than
one that is five degrees less than the launch angle that yields maximum
range.

2. An accelerometer is a motion sensor. I don't know if it is still the
case (I suspect that it is) but back in the 70's I think that the
software on an ICBM was programmed to integrate accelerometer output to
determine the velocity of the payload at the current instant in time and
to integrate again to get the position at the current instant in time,
given initial velocity and position information. Values of the position
at successive instants could be used to generate a graph of position vs.
time. A sonic ranger available in some high school laboratories can
also be used to produce such a graph. A force probe with software
programmed to apply Newton's 2nd Law to an object of known mass could be
used to generate such a graph. The force probe or the accelerometer
would undoubtedly include a potential difference probe. Any one of the
four answers can be considered to be correct. Which is the best answer
is probably a matter of opinion. The question highlights what I
consider to be a problem with the California Standards test that is
shared by many tests. Ruling out many distracters sometimes requires a
lot of words. Test question writers seem to follow an unwritten rule
that the questions must be short. I think that critical reading skills
are an important part of physics improved critical reading skills should
be considered an important outcome of any physics course or program.
Being able to read a long question with words that unambiguously rule
out distracters is a skill that should be tested in a physics test.
Embrace the wordiness required to pose a good question. If this means
asking half as many questions, so be it.

10. This question and its answer reinforce the idea that weight is a
property of an object. How hard does the moon pull on the book when it
is near the surface of the moon? How hard does the earth pull on the
book when it is near the surface of the earth? A better answer than
weight, to the question posed on the test, would be the gravitational
force exerted on the book by the earth. Aside from being part of an
assessment tool, a standards test is a teaching tool. Reject any
question that can be expected to teach the student something that is
wrong.

Jeff Schnick


Dean Baird wrote:

Hello All,
The California Department of Education took a little more time than
anticipated this year, but the newly-updated Released Test Question
documents are now posted. There are now 60 questions released from
previously administered California Standards Tests in physics.
Fifteen of those 60 are new for this year; they were used on the
2006
test.

You are free to download them, use them, comment, and criticize. As
a
member of the state's Assessment Review Panel, I am always eager to
know what my colleagues think of the questions. Here's the link to
the PDF:

http://www.cde.ca.gov/ta/tg/sr/documents/rtqphysics.pdf
<http://www.cde.ca.gov/ta/tg/sr/documents/rtqphysics.pdf>

The fifteen new questions are items 1, 2, 10, 12, 16, 23, 27, 32,
34,
40, 41, 46, 54, 58, 60.

I posted a note with more information on my blog: http://
phyzblog.blogspot.com/2007/02/cst-questions-released.html

Let me know what you think,
Dean Baird
Rio Americano High School, Sacramento

cut

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