It's important to note that the author's intent is not to deride test-takers for common mistakes, but rather to describe the observations he made as a first-time AP Physics exam reader (grader).
After a 5 year wait, I final received the opportunity to become an AP reader. My primary goal was to learn as much as I possibly can to become a better teacher. Here are things I noted.Responses to von Steen's post indicated some variation of interpretation among readers. But the variations were relatively subtle.
1. A lot of students thought that work is always positive (never negative).
2. A lot of students thought W = F x t , W = F / d , W = F x v and F = mat.
3. If a student put down the correct numerical answer, but showed no work, they could get 0 pts and 1 pt at most.
4. A student could have math errors and still get maximum points.
5. On an FBD, if the directions say “on the dot below” draw the force vectors …., If the student draws force vectors that don’t touch the dot (even though they are correctly labeled and pointed in the correct direction), they could lose credit (I learned this one at the lunch table).
6. Readers don’t like grading the lab question.
7. I’m going to tell my students when “Justification” is requested, use formulas and calculations to justify your answer as oppose to words. The more words they write the more likely the reader is going to over look a correct answer. Example: W = F x d = -15 J (easy to spot and give credit) as oppose to ”Work equals forces times distance which will be a negative numbers” (hard to spot especially embedded in a lot of text). I looked back now and wonder if I missed giving some desiring students credit.
8. Don’t use the word “it”. I don’t know what “it” is. I saw students write “it is decreasing”. I don’t know if “it” meant acceleration, velocity or my bank account after the children are born.
9. A lot of students thought work was a vector.
10. Watch out for the decimal point in the given. The problem was given 0.40 kg and a lot of students wrote F = ma = (4)(2) = 8 N and missed an easy point.
11. “Check” the box(es). Some students didn’t do any work but checked the correct spaces and got credit and (sadly) one student got no credit because he/she check no boxes even though they stated the correct box to be checked and had the correct justification (we have to go by the rubric).
12. I thought that the students didn’t have to memorize any numbers, but the only way to answer the very last problem of the exam 6. d) ii) is they had to memorize the wavelengths of visible light. I was told it is in the “acorn” book, but I couldn’t find it. Which makes me think that there are other numbers out there that my students are require to memorize.
13. It looks like the AP Physics redesign will be a step backwards. I didn’t hear anybody liking it public or privately. I’m luckier than most. I’m able to get the whole curriculum in but my students will take 2 exams for 6 hours instead of 1 exam for 3 hours (and yes they paid for both). I can see the redesign killing some AP physics programs and overall less students taking the exam.
14. The food was “ok” (not as great as I heard it was). I got tired of recycled green beans, lettuce and potatoes every day.
15. I met a lot of smart people that I learned from. I hope they ask me back next year.
You tend to see things when you're a wide-eyed first-timer that you don't always see when you're a sage veteran. And this first-timer was willing to share. Students might appreciate these insights as they go into the exam in May.