This is from an online pre-class assignment:
Here is a physics problem! Imagine you are driving a car along a long straight. Your friend in the passenger seat is recording where you are every hour of the trip.
Explain why your friend might reach the conclusion that the speed of the car at 3:00 PM was 24 miles/hour.
Then explain why that answer is probably not correct.
Well someone might get 24 miles/hour by dividing the mile marker (72) and the given time (3:00 PM) and think that would be the miles traveled in that hour. But just because you are at a given mile marker that does not tell you speed because you are at that mile marker for only an instant, so it would be calculated as no speed.
- What is the student thinking? Why do think it made sense for the student to write this answer?
- What other knowledge and experiences might we presume the student has for thinking about this question? Why do you think the student failed to draw on this knowledge when answering the question?
- What question or problem would you pose next to help the student make the next step toward understanding?