- #1
ChrisXenon
- 60
- 10
Hi Folks, I am a private tutor and one thing I teach is A level Physics (OCR Physics A).
Am I the only person who has been sometimes baffled and deeply disappointed with some of the questions/answers? Let me explain what I mean.
I see questions form which it's not possible to decide what kind of answer is required; when you look at the model answer to see that their interpretation is entirely arbitrary.
A recent example invites the student to describe the motion of a body whose upward velocity is decelerating due to gravity. The marking scheme expressly forbids the term "rate of acceleration", yes in the next question it allows that term.
I finally wrote to OCR to get clarification. They said:
I completely understand that science demands a greater level of terminological accuracy than ordinary discourse, but I say it's entirely OK to say "rate of acceleration decreases". When I asked why they penalise it once but allow it in the second instance, they said it was unreasonable to penalise its use twice.
Here's another problem in the same question.
They also disallowed "acceleration" requiring "deceleration", but in my view, all deceleration is acceleration in the direction arbitrarily defined to be negative. You can say "the acceleration is negative" or you can say "the body is decelerating". So again, I think their position seems arbitrary and founded on nothing.
What do you think? It's important for me to get this right for my students.
Thanks
Chris
Am I the only person who has been sometimes baffled and deeply disappointed with some of the questions/answers? Let me explain what I mean.
I see questions form which it's not possible to decide what kind of answer is required; when you look at the model answer to see that their interpretation is entirely arbitrary.
A recent example invites the student to describe the motion of a body whose upward velocity is decelerating due to gravity. The marking scheme expressly forbids the term "rate of acceleration", yes in the next question it allows that term.
I finally wrote to OCR to get clarification. They said:
"A dictionary definition of 'rate' states that it is a measure, typically measured against another quantity or measure, particularly against time, with examples such as crime rate, interest rate, mortality rate.
A common technical use of rate in science would be rate of flow, a volume in a given time."
A common technical use of rate in science would be rate of flow, a volume in a given time."
I completely understand that science demands a greater level of terminological accuracy than ordinary discourse, but I say it's entirely OK to say "rate of acceleration decreases". When I asked why they penalise it once but allow it in the second instance, they said it was unreasonable to penalise its use twice.
Here's another problem in the same question.
They also disallowed "acceleration" requiring "deceleration", but in my view, all deceleration is acceleration in the direction arbitrarily defined to be negative. You can say "the acceleration is negative" or you can say "the body is decelerating". So again, I think their position seems arbitrary and founded on nothing.
What do you think? It's important for me to get this right for my students.
Thanks
Chris