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[Physltest] [Phys-L] Re: California standards test in physics



On Thursday, January 06, 2005 10:40 AM, Marc Kossover wrote:

I will also insert my standard complaint that, like
most state tests, the released questions are at a low
conceptual level. Further, the test includes many parts which
are frequently taught in chemistry and includes virtually
nothing interesting from optics.

At least they match the low-level nature of the CA state standards.

On Thursday, January 06, 2005 10:32 AM, John Denker wrote:

One-dimensional vectors are isomorphic to plain old numbers,
and can be considered positive, zero, or negative.

Yes, an unfortunately, there is no way to know if up is to be positive
or negative.

As for the velocity question, I've been using a question the past couple
of years in my class in which, I hate to admit, I made the same mistake.
I didn't catch it until I noticed that, year after year, performance on
the question actually went DOWN (pre to post).

While we are critiquing the CA questions, what do people think of
question #1?

1 A student does an experiment to measure the acceleration of a falling
object, which is 9.8 m/s2 . The student obtains an experimental
value of 14.6 m/s2 . The reason for this variation is most likely due to
A human error.
B air resistance.
C local fluctuations in gravity.
D the mass of the object.

It seems that a lot of students want to think that any difference
between their measurement and the predicted must be due to human error.
It takes a long time for them to recognize the influence of measurement
uncertainties. I'm afraid that question #1 (although A is the most
reasonable of the given answers) inadvertently reinforces the tendency
for students to blame human error for any differences.

Also, how about question #5?

5 A 10-newton force and a 15-newton force are acting from a single point
in opposite directions. What additional force must be added to
produce equilibrium?
A 5 N acting in the same direction as the 10-N force
B 5 N acting in the same direction as the 15-N force
C 10 N acting in the same direction as the 10-N force
D 25 N acting in the same direction as the 15-N force

What does it mean to say that forces act "from" a single point? Is this
language used because the tails of the force vectors are typically
placed on the object upon which the force is acting? What do people
think about the use of this language?

How about questions 18-20? All three are similar. Number 18 states
that pressure increase is related to temperature increase and asks why.
How is this different from #20:

20 When a gas is heated in a closed container, the internal pressure
increases. Which best describes the reason for the increase in
pressure?
A The average kinetic energy of the gas molecules decreases.
B The potential energy of the gas increases.
C The average kinetic energy of the gas molecules increases.
D The potential energy of the gas decreases.

- is #20 really asking for a reason?

How about question #24?

24 Astronauts on the Moon would not be able to hear a landslide because
A the lunar dust deadens sounds.
B intensive sunlight destroys sound waves.
C the magnetic field of the Moon is too weak to carry sound.
D air molecules on the Moon are too far apart to carry sound.

How far apart are the air molecules on the moon? How far apart do they
have to be in order to be incapable of carrying sound?

____________________________________________________
Robert Cohen; 570-422-3428; www.esu.edu/~bbq
East Stroudsburg University; E. Stroudsburg, PA 18301
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