Category: HSC Physics

4 ways to avoid common errors in HSC Physics

Getting those few extra marks can be tough. Not only does the HSC Physics exam test our knowledge of the subject but also our ability to convey that to the marker for any given question. Getting everything down onto the paper itself is a milestone, and that’s before you count the challenging questions that can leave you stumped! Then you get your paper back, aside from what you expected… There are all the careless mistakes and marks taken for seemingly frivolous things like the heading to a graph. HSC Physics sure is tough, but here are four ways to avoid those unexpected surprises that we can all do without!

1. Always check the units

Everyone knows about checking the units in your final answer, but have you ever considered the units the question comes with? It seems obvious, speed is in m/s and frequency is in Hertz. But the place where many students trip up is in the Space module, most of the measurements in the question are given in kilometres however all the equations in the data sheet are based on SI units so are in metres. Remember to times by 1000 in these cases and watch out for other prefixes like micro- and nano- when doing wavelength calculations. Always think about your answer, if the altitude your orbiting satellite is 100 metres you should probably try again!

2. Underline the key words of the question

You’ve probably heard this piece of advice time and time again. However, hardly any students end up following the advice. I remember wishing I had taken the effort to underline the keywords in the question when I lost that easy mark for not giving a final evaluation in a 7 marker. Teachers and physics tutors would have told you that the main reason for underlining the words in the question is to make sure you’ve covered everything. While this is true, we all know it’s all too easy to underline and forget! Make sure you tick of each piece of underlined information so that you truly haven’t missed anything and get the most out of your efforts!

3. Use a diagram or table

Tackling those large mark questions is tough! The very thought of having to write down all that information used to dishearten me! I’ve found that the easiest way to reduce both the time and effort taken for these questions is to use a table or a diagram. At school or at physics tutoring, they normally recommend you do this for questions that have the key words "compare and contrast" but you can use this method in many more cases. A table can be used for "discuss" questions and "evaluate" questions while a diagram can help with explaining the galvanometer, induction cooktop or even the nuclear reactor to name a few. Not only are these diagrams and tables more readable, they also help you remember all the things you want to write about as you remember it in a visual fashion. Dot-points can also be used when answering questions normally in order to save on writing which can really help out on the 3 hour papers. Remember your diagrams and tables and fight back against the wall of text!

4. Leave time to check

This rule is almost universal to every exam and in a perfect world we all wish we could do it. Leaving time to check is an approach that shapes how you tackle the whole exam. If you want to save time in the exam, it’s best to practice earlier, the most straightforward way is doing all the practice papers in about 75% of the actual time in order to develop speed. Additionally, with more practice questions will become easier to answer and you will spend less time trying to remember the points. While we can save some time for checking, it isn’t infinite and needs to be prioritised. The first thing to check is always the mistakes you make most commonly so as to pick up the easiest errors first, then checking the calculations by doing them again separately and lastly by adding anything at all that could be relevant to the answer that you can think of! Remember, as long is its right, it can’t hurt. This method for checking means that even if you run out of correction time you’ve been as efficient as possible with your time meaning better exam performance.

A student’s worst enemy is the marks they could have gotten but missed out on. The above methods stem the tide against losing ‘easy marks’. Hopefully they help you get those last few marks you’ve been yearning for in HSC Physics!

HSC Physics – Tips for Success

Doing well in HSC Physics requires a good mix of different skills. You’ll mainly need to be great at understanding physical concepts, understanding their impacts on society / environmental issues, being able to form cohesive arguments to support your answers, and command some basic maths skill. There’s already a tonne of articles on the blog or forum posts dealing the more conventional study tips, so we thought we might cover some often missed points on the subject. So doing well in HSC physics involves:

Always refer back to the syllabus

All HSC physics exams, whether internal or external, will have to test students within the bounds of the syllabus. Syllabus dot-points are worded in a way that makes them look like exam questions (or the exam questions you get are simply paraphrasing certain syllabus dot-points). If you prepare brief notes covering every dot-point before each exam, you’ll guarantee yourself the knowledge needed to score a decent mark at the least. It is therefore a great idea to make yourself syllabus dot-point summary notes for this subject. Unlike English or Maths, the HSC sciences syllabi are extremely prescriptive, which means everything that can and will be examined are written in black and white on the syllabus for all to see. Know all your dot-points and you won’t go wrong.

One caveat to this approach however are sometimes school teachers may insert ‘creative questions’ that may exceed the bounds of the syllabus because it was covered specifically in class. Can’t blame your physics teacher if this happens (firstly because it’s hard to prove as the syllabus is open to interpretation and secondly the teacher has the last word anyway so even if you’re right, you still won’t get the marks). The best thing to do is to always pay attention in class in addition to knowing the syllabus back to front.

Don’t forget the prac exam

It’s easy to forget the practical / first-hand-investigation requirements of the syllabus. For most students, your internal assessment consists of: term 4 assessment, half yearlies, trials paper exam and prac exam (not necessarily in this order – the prac exam could be the first thing or the last thing you do in the year). The prac exam will be worth around 15-25% of your entire internal assessment mark, so it’s something worth studying for. The best way to prepare for this is to ask students in years above what their prac exam was. Because prac exams require equipment, (and unless you go to a private school with unlimited faculty budgets) chances are each year will be the same prac exam. So if you’ve got friends that graduated in recent years, ask them (if not, ask friends of friends – knowledge is power!) You can also deduce that some pracs won’t be the subject of your exam as they require dangerous activities (projectile motion – they don’t want 20 students in a class throwing projectiles around for 90 minutes) or costly breakable equipment (cathode ray tubes).

Once you know what experiment you’ll be doing for your prac exam (probably the pendulum experiment) you’ll need to familiarise yourself with every aspect of the experiment so that the day will go smoothly when it comes to actually doing the prac. You’ll also have written response questions as part of your prac exam, so prepare answers to the following questions:

  1. Were there any safety issues you needed to manage / be aware of?
  2. What about sources of error? How would you account for differences between actual and theoretical values?
  3. Identify the dependent and independent variables. Identify the control and test variables
  4. Think about any graphs you may need to draw. If it involves a line of best fit over collected data, would it make sense to pass through the origin or any particular data point?

Power of the thought experiment

One of the most important factors to any part of HSC Physics is your ability to conduct thought experiments. Thought experiments are when you play a scenario out in your imagination to test the validity or absurdity of a concept you want to test. This technique is useful in many parts of the course. For example, suppose you forgot details of the effects of re-entry (Space module). You could derive everything again on the spot just by thinking it through step by step:

  • The shuttle begins in space, and as it enters the atmosphere, friction with air particles slow it down. The friction heats up the air particles to a plasma (and we should know ionised gas blocks radio waves) so this leads to the loss of radio communications during re-entry (called ionisation blackout). The extreme heat of re-entry requires deflection (shuttle needs heat shields). Also the rate of deceleration depends on the angle of re-entry, so there must be an optimum angle.

Another useful application of this is where you forget how to use a formula because of some minor confusion. All you need to do is to apply a hypothetical situation to how you think the formula works – if it leads to an absurd result, you’ll know it’s incorrect and that you should apply the formula differently.

 
 

Contact

Phone:(02) 8007 6824
Site: www.duxcollege.com.au
Email: info@duxcollege.com.au