Thursday, February 01, 2007

CST QUESTIONS RELEASED!

The newly updated Released Test Questions for the California Physics Standards Test are now available. Each year, the California Department of Education releases 25% of each CST administered the previous spring. This process has been in place since 2003, so we now have access to questions released from the the 2003, 2004, 2005, and 2006 tests.

The Physics CST is 60 questions, so each year, 15 questions are added to the pool of RTQs. The physics RTQ document now has 60 questions. You might think that with 60 questions, the RTQs now constitute the equivalent of an administered, "live" test form. But you would be in error. The nature of RTQ selection and live test form construction are such that no, the RTQs do not match the blueprint of an operational test form.

The RTQs do constitute useful practice test items. They show the breadth and scope of typical test questions. You can get the newly updated physics RTQ document here:

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

I recommend running these questions past your students before this year's live administration.

Feel free to send comments and criticisms to me. I serve on the state's Assessment Review Panel, so I may have recommended some of these questions for use on the live form, and I may have recommended them for release in this document. If you find fault with any of them, I ask that you engage in a corrective discussion with me so that I might serve better in future reviews.

For readers eager to evaluate the worthiness of the newly released questions, they are items 1, 2, 10, 12, 16, 23, 27, 32, 34, 40, 41, 46, 54, 58, 60 on the new document.

If you want to see the full offering of newly updated RTQ documents, visit this page:

http://www.cde.ca.gov/ta/tg/sr/resources.asp

5 comments:

Anonymous said...

I'm uncomfortable with all of the questions on the first page. I'll look at the other questions when I have time. But here are some comments on the first 4 questions.

1) The phrase "most easily" bothers me. I typically make plots using a computer program, and I am very comfortable inputting data into a spreadsheet or a database.

2) What does "real-time" mean in this context? In fact, I can make graphs of displacement vs. time and velocity vs. time using all the tools provided. And further, a typical motion detector directly measures position vs. time and calculates velocity vs. time. Also, lots of students do video analysis. What about students who have never used these particular measuring devices?

3) I'm literally aghast that the answer is "human error". Sorry that I don't have anything more constructive to add, but I really dislike this answer.

4) Answer choices A and C are both valid. From the image, I conclude that A accelerates downward while B moves at nearly zero acceleration. If the air resistance of A is smaller than its weight, it will accelerate downward. If the mass (and thus weight) of the object is larger than the air resistance for the period pictured, the overall acceleration of the object would be also be downward.

Anonymous said...

I agree - some of the questions here are quite odd. Of course, I knew the answers that they wanted but why ask questions that are somewhat ill posed?

In particular - question 3 shows some real misunderstanding of the basic concept of measurement. When ever one makes a measurement you need to assign an uncertainty to it. Perhaps there were systematic effects that could not be understood - and the uncertainty was as large as 4 m/s2. This would only be one sigma off the well measured value and a perfectly valid - though not very precise - measurement.

Anonymous said...

I also noticed that apparently the standard high school physics curriculum still stops in the 19th century. I understand that it is difficult to cover such a broad number of topics in a standard high school year. However, I feel we are doing a real disservice by not even mentioning anything that happened in the 20th century. For example, its been more than 40 years since the discovery of quarks and most Americans don't know they exist! To me its like teaching a Biology class but never mentioning DNA. Its not as academic as you might think - modern technology is based on understanding quantum mechanics. GPS takes into account General Relativity!

John M. Clement said...

The comments about number 4 are certainly correct. As to the amount of air resistance, since the first object is moving faster at the end it could have the same air resistance as the smaller object. Also one should never use the word slower or faster in describing acceleration. It just produces added confusion between velocity and acceleration.

I would say that the first 5 questions are pretty bad.

Number 5 is also a bad question. The answer could certainly be a conclusion based on experience. Indeed one does not have to know theory to make the conclusion, as experience with circuits is all that is necessary. The line between hypothesis and conclusion can sometimes be fine. A hypothesis can be a grand name for a guess. As to the obviously silly answer involving theory, it may reinforce the usual misconception about theories. Usually when questions are asked about these types of things the questions are very bad. Even many good publications and authors get it wrong.

Number 6 is also poor because neglecting a known effect is not experimental error, but experimenter error.

Number 10 is just a vocabulary question masquerading as a Newton's third or second law question. It purports to test the second law, but really does not.

Stevie Ray said...

I think Question #14 was written by folks who do not understand the term "instant". At "...the instant the student pushes off..." (which to me is ambiguous at best and certainly does not fit the graphics shown) there would be an INSTANTANEOUS READING on the bathroom scale and therefore readings that change would be impossible. The given correct answer (B) would make sense if the situation were: "What does the lab partner observe from the time the student pushes off the scale to the time the student's feet first leave the scale?" This situation would also match the graphics shown for this question. It would be interesting to check how many students actually got this question correct on prior versions of the test where this question appeared. They surely do NOT understand the concept of "instant." I wonder how well they understand acceleration which deals with changes in Instantaneous Velocity?