In this post, the Matrix Science Team show you how to answer "Explain" Physics questions.
In the 2014 HSC Physics Exam, there were 9 questions that involved the following key verbs:
See the complete Glossary of Key Words.
Did you know that most students lose a mark or two when answering these questions? If you were to lose one mark for each ‘Explain’ question in 2014, it would equate to at least 4 marks! The seriousness of this problem is highlighted by the HSC Marking Centre every year in ‘HSC Notes from the Marking Centre’
Students can generally benefit by correct interpretation of questions
Let’s read the ‘Common Mistakes’ that students make in Part (B):
Examiners provide reports after each HSC exam that indicates areas of strengths and weaknesses in student responses. From these common mistakes, it is clear that students generally can benefit by:
The 6 most common mistakes HSC Physics students make in exams article lists several additional common mistakes that are frequently made in exams, such as insufficient workings for calculations and mistakes made when drawing a line of best fit.
‘Explain’ is an extremely common key verb used for 2-3 mark exam questions. The Board of Studies Glossary of Key Words defines ‘Explain’ as “relate cause and effect; make the relationships between things evident; provide why and/or how.”
Many of the questions in Physics are about explaining the physical link between cause and effect. Let’s look at ‘explain’ questions from 2014 HSC Physics Exam Paper:
‘Explain’ questions tend to have the following structure:
When answering questions involving ‘Explain’, students should consider the following structure:
Explain links a start point to a conclusion using scientific arguments and needs a sequential flow of logic and from start point to finish point. Let’s answer an explain question using the structure outlined above.
QUESTION (2014 HSC Q25b – 3 marks):
Explain how the motor effect is used in an AC motor.
Step 1: Identify the start and finish point
Explain how |the motor effect |is used in an AC motor|
Start to Finish Point:
Finish to Start Point:
Sample Answer 1:
Sample Answer 2:
This is not as natural in this question, but it is still a valid explanation response. In other questions there is no difference.
Notice the logical links between the points in Answer 1 are which results in or therefore (⇒, ∴), and the links between the points in Answer 2 are caused by or because or since (⇐,∴). Both answers thus feature a logical argument from start to finish.