How to study for quizzes

Table of contents:
Before studying for the quiz
Studying for the quiz
In the quiz

I am commonly asked how to study for "the quiz" for physics 7. These notes are meant to guide you through that process. You should note that they are not a shortcut or a cheat sheet. Because everyone learns differently, it would not completely surprise me if the statements about how to study don't apply to you. This document can still be useful in explaining what we expect you to get out of physics 7 so that you can decide what your most effective learning strategy should be.

What are we trying to teach

What we are trying to teach is a way of how to think logically. Many other classes require you to memorise a series of facts. For example, in biology it is far too complicated to work out what a given cell part does or how it works. So instead you are taught what the different pieces of the cell are, their names and their functions.

Physics is slightly different. Because we are interested in general principles, we can often explain why things are the way they are in terms of a few unexplained axioms. For example, we don't tell you why energy is conserved but once you accept that it is you can explain other things in terms of it. For example you can answer why a ball will reach a maximum hieght instead of going up forever if you throw it up with only a little speed, or how atoms can only be a certain distance apart.

Before studying for the quiz

Using the DL notes

There is a lot of information in DL, but as mentioned above the main point is not to try and memorise a lot of that information. Instead, the idea is to get familiar with a particular process (such as energy diagrams). Things like the form of the Lennard-Jones potential are less important than you being able to use the conservation of energy to make statements like where the particle is trapped.

While the focus is not on memorising, there are certain facts that you do have to memorise and then use these in your explanations. For example:

Things you must get right

Energy is always conserved.
Temperature does not change during a phase transition.
E_bond only changes at a phase transition.
KE is never negative! (KE = (1/2)m v²)
E_thermal is never negative!
KE = (1/2)m v². Because you can measure m and v, there is no arbitraryness in KE.
We cannot measure PE or E_tot, so those depend on what we call the "zero of energy". (Usually this is at infinite separation and no kinetic energy, but this is only a convention).
No physical system with energies unbounded above can have a temperature less than 0 Kelvin.
Although not important in this class, you actually can create negative temperature systems! For example, the electrons in atoms that make lasers have negative temperatures. The weirder thing is that negative temperature systems have more energy than infinite temperature systems! Because you are dealing with systems that you can always add more energy to, you will never get temperatures less than 0 K.

Keep a list of these facts, and update it after each DL. Once you have finished your quiz, check each of these as appropriate. For example, if asked to plot KE make sure KE is never negative. If you get one of these wrong, you are likely to get a very low quiz score.

(What you choose to write depends on what helps you. For example, I think it is obvious that E_tot includes all the energies in the system added together. This is not obvious to you, put it on your list of things to remember to check!)

Then there is useful information that you should know, but is more specialised than the above. For example, knowing the formula for PE_mass-spring. While it is important, not knowing it or using a slightly wrong formula does not show a complete lack of understanding. Thus, if doing last minute checking on a quiz it is more important that you get the things on the first list done.

Also consider what things that you or your classmates have trouble with in DL.

It is also worth thinking about the limitations of these facts. For example, if we have a mixed phase is it always true that the substance is at a phase change temperature? NO! For example, a lit candle has a solid outside (much cooler than melting point), liquid and solid in the centre at the melting point and liquid at a higher temperature at the melting point. Anyone who has stuck their finger in a candle knows that different parts are at different temperatures! Instead, it is true that a mixed phase only exists at a phase change temperature for a stubstance in thermal equilbrium. Keep thinking about how physics relates to your everyday experience, and if we are telling you something that does not match up then call us on it!

Doing the FNTs (and getting stuck)

In order to do be able to know what you find confusing, before you ask a TA a question about an activity go through the following steps. The best way of doing this is to write them down somewhere, so you can refer back to them.

What is the question asking for?
What sort of approach should I use? For example, should I use energy conservation, three phase model, force diagrams (7B and C only) etc. What hints are there in the question or information given that I should use this approach?
What information do I have?
What would normally be the next step I would do when doing these types of problems? What additional information do I think I need to make the next step?
If I have too many unknowns, is there a way that I can make the problem simpler? (The most common example of this in 7A is choosing different intial and final points)

Instead of asking the TA how do I do this problem, go through how far you got and where you got stuck. Then ask the TA where you went wrong, and what hints there are in the question (or information given) that this was the wrong approach to take.

Studying for the quiz

Using your DL notes

Your DL notes will cover the important things that you have learnt that week, and the things that will be on the test. You should isolate:

Which items you have to memorise
How did you show other properties in activities from those new concepts

It is even better if you can put the things you have to memorise into a real world context, so that they make some sort of intuitive sense to you. Remember that there should not be that many memorised concepts -- if there are you probably have misconceptions, and you should e-mail your TA or go to office hours.

An example of such a misconception is to thing " because PE goes down, KE must go up". This is wrong! For example, the Atwood machine is a counter-example. This rule seems to be true only because a lot of physical systems we deal with only have PE and KE, and are closed. Then this rule would.

After you have a new rule that you think always applies, it is worthwhile spending about 5 minutes thinking if you can come up with a counter-example. That is, is it really a rule that is never broken (like conservation of energy) or is it just a rule that you have come up with because you have only seen a finite number of examples (like the PE vs. KE argument above).

Finally, ask yourself what the most difficult thing to get in the lab was. Pay particular attention to where you use negative values, as those are troublesome for students! Don't think that just because you understand the example in DL that you have got it -- try making up an example that you can do. Then give it to a study buddy and see if they get the same answer you do!

Using the FNTs

The FNTs are a good source of problems, although they are not exactly what you will see on a quiz. There is a reason that they are different:

The quizzes are designed to make you stop and systematically apply the methods you have learnt, not just to write out the FNTs over and over so you memorise the answer.

To use the FNTs effectively to study from, I would follow this guide:

Look at the FNT. What method are you supposed to use to solve this question? What hints are there in the question that this is an appropriate method to take?
Could I do this FNT before going over it in class? If you couldn't, review your list of things that would have helped you from before. Can you think up a similar question that you could review?
Many of the FNTs involve calculations. Can I remove the numbers and still end up with an explaination? Can I change the question so that it is more conceptual?
(A good way to do this is often to compare two slightly different cases)
Is there a way of making this problem different?
If studying in a pair or triple, try changing the FNT slightly (change the reference point, change a couple of numbers, compare two cases) and give it to your study buddy to do. See if you agree with their explanation on how to do that problem.

Again, it is important to emphasise not to be too proud. If you had trouble with your FNTs, you should write yourself the notes outlined before. The hardest part is getting people past the "I didn't know how to do that problem, but now after DL I think I can" stage to the stage where they can identify what they think the problem is.

(Asking your TA what to study for the quiz is almost pointless, as the best thing to study is the thing that you personally had the most difficulty understanding!)

Examples of these methods:

The skiing problem
The ball and block up a hill problem
An air resistance problem

Additional problems and resources

I think that in physics 7 there are not enough problems for you to look at. Doing physics really means trying many different problems, getting practise at how different concepts inter-relate and building your own understanding of the real world.

Here are some sources of additional problems for you to look at while studying:

Physics 7 course notes, page 90 to end
Granted, it is only about 8 problems and I think if you wrote these answers down you wouldn't necessarily get a good grade. The section and explanations on entropy in particular are pretty bad. The yo-yo problem invokes the no-slip condition, which never actually gets covered in 7A. Still, its there and you (should) already have it.
"Thinking physics", Lewis Epstein
This book will not turn you into a rocket scientist, as all the questions are conceptually based. However that makes it an excellent aid for this course, and it is also (relatively) cheap!
"The Flying circus of physics with answers", Jearl Walker
This is also an excellent source of questions, but may be frustrating as it is not organised into topics. If you are enthusastic about learning how to answer simple questions like "why do stars twinkle?" then its a good book, otherwise I would pass on it.
"Conceptual physics", Paul Hewitt
An expensive text that comes with very mixed reviews. The library has two copies, check these out first. Maybe try his Introductory physics book instead.

Of course, the cheapest one is to ask your TA for a question on a particular topic. Depending on the number of other demands the TA has, they may be able to provide you with some appropriate level questions.

In the quiz

Okay, so now you are in the quiz and it is time for all your hard work to be shown off to the grader. If you get the question and really have no idea what to do, then you did not learn what was intended of you. Otherwise:

Don't panic if you don't see the answer straight away!: Ifyou know what sort of approach to take, then start with that. Give quantities you don't know variable names and then list what you know about them. For problems involving initial and final points write out the indicators.
Initial and final points: Especially if describing more than two sub-processes, make sure it is clear what your initial and final points are. The easiest method is to draw a picture and label points on it 'A', 'B', etc. Remember it is up to you to convince the grader that you know what you are doing.
Write out all algebra on a quiz: If doing energy interaction, leave the unknown quanities as question marks, write out your expression of energy conservation and then box it. Then do your algebra and solve for the unknown. This makes it easy for the grader to see what you have done, and give you marks for what you have done.
Check your answer (against principles): Make sure that you don't violate any of the important rules you have learnt. Have you said the object will have negative kinetic energy? Have you said it starts with zero KE, which then decreases? Have you got a negative temperature?
Check your answer against itself: Look at your indicators and your bubbles. Have you said that PE was increasing, and yet solved the problem for a lower height?

Finally, if you are out of time on a quiz but have found that you have done something wrong, write that the answer is incorrect on the quiz. It will count for something that you are checking your answer to see that its physically "sensible".