Tackling Long Answer Questions – Top Revision Tips
In the UK the new A Level and GCSE exams include 4-6 mark questions which require an in-depth written answer several paragraphs long.
These long answer questions come in certain types and test the higher level thinking skills of interpretation and explanation (creating a logical explanation for a scenario), synthesis (pulling ideas from different areas together) and evaluation (weighing up options or outcomes). They also award a mark for clear written English and a well structured argument.
Long answer question can put the fear of God into many students who never seem able to break the 3/6 mark barrier and achieve the higher marks.
Thinking Skills in Long Answer Questions
Some questions on exam papers are easy, 1 mark for recalling the charge of an electron for example. These questions usually come with a certain prompt or command word which indicates you have to remember a fact but not actually do anything with it. “State the definition of electric current” is a typical, “name”, “give”, “what is…” etc are all command words for rote recall questions.
Long answer questions are different. Usually they give quite a lot of information before stating what you must do with it. They are setting the scene and every word used to set that scene is important. Examiners spend hours getting the phrasing of exam questions just so. If they have told you about the efficiency of a power station in the introduction to the question, you HAVE TO mention that in your answer.
The skills you need to answer these questions go beyond just including the larger amount of information these questions give you. Here is a famous pyramid called Bloom’s Taxonomy. Benjamin Bloom was an American educational psychologist who chaired a group which first devised this taxonomy (or classification) of command words into groups according to the level of brain power needed to complete each task.
Long answer questions are targeting the top three layers; analysing, evaluating and creating. These skills involve selecting the most important information, working out which order to put it into, identifying the key bit of physics the question is about, linking in related principles that may not be explicitly stated in the question and offering a solution to the problem solved. What makes this hard is holding all these aspects in mind at the same time.
Let’s look at an example:
- Identifying the most important information: They tell you up front it is about the Big Bang. They mention the CMB radiation, they give you wavelengths.
- Key bits of physics: the origin of the CMB, probably need to relate this to wavelengths somehow, the idea of the expanding universe, OK that’s Hubble’s Law, then wavelengths from galaxies which must mean cosmological redshift tying in with Hubble’s Law. OK sorted.
- What order to put them in: “Explain” command word, 2-3 marks for explaining the role of CMB in Big Bang theory. Go on to discuss how present day Universe must still be expanding and how we could show this, 1-2 marks, relate data from the table to this. Have to use an equation relating wavelength at rest and in galaxy to redshift or recessional velocity. Need to use data they have given me, 2 marks for working out the redshifts. “Comment” command word, finish off with remark about how the data is relevant.
How to Tackle Long Answer Questions
The main strategy is not to read the question and immediately start writing, DON’T DO IT!
Here is a printable infographic which breaks down how to tackle these questions.
Step 2: Annotate the question is identifying the most important information
Step 3: Jot down ideas is recognising the key bits of physics to use
Step 4: Sequence your ideas is working out what order to put them in
Types of Question
Now we know how to go about answering these questions let’s consider certain types of question that crop up.
1) Experimental Design
Describe how you would compare … in a laboratory. Billy Bob wants to determine Planks Constant using LEDs, outline an experimental method which would….
The main things to include are apparatus, preferably a labelled diagram, brief method stating what you change, what you measure and what needs to be controlled. Give the range over which you take readings using the equipment you chose. Mention how many repeat readings you take. State two (or more) measurements will be plotted and what data processing you may need to do to find the desired result. This could be a simple as saying we divide voltage by current to find resistance, or you plot an I-V graph and work out the gradient. But you must say what you intend to do. Experimental method does not mean JUST apparatus and method. You must talk about range of data, reliability and data processing as well.
The marks for this question were awarded as follows:
Equipment used safely (E)
- Wire fixed at one end with load added to wire
- Suitable scale with suitable marker on wire
- Micrometer screw-gauge or digital/vernier callipers for measuring diameter of wire
- Referencing to safety concerning wire snapping
Measurements Taken (M)
- Original length from fixed end to marker on wire
- Diameter of wire
- Measure of load
- New length of wire when load increased
Calculation of Young modulus (C)
- Find extension (for each load) or strain (for each load)
- Determine cross-sectional areas or stress
- Plot graph of load-extension or graph of stress-strain
- Young modulus = gradient x original length/area or Young modulus = gradient
- Calculate Young modulus from single set of measurements of load, extension, area and length.
Reliability of results (R)
- Measure diameter in 3 or more places and take average
- Put on initial load to tension wire and take up ‘slack’ before measuring original length
- Take measurements of extension while unloading to check elastic limit has not been exceeded
- Use log wire (to give measurable extension). Scale or ruler parallel to wire
To get 5-6 marks you had to include all points E1, 2, 3 and 4 for equipment, all points M1, 2, 3 and 4 for measurements and for the calculations you were expected to show C1, C2, C3 and C4.
Each specification says which experimental methods students should be familiar with and you can practise these questions by ticking off each experiment in turn and writing your own diagram, method, data collection and calculation notes.
2) Big Physics
We have seen an example in the previous section. Big Physics is particle accelerators, the Big Bang, life cycle of stars, fission and fusion, MRI scanners etc. These questions ask for descriptive explanations of the phenomena. Quite a lot of which is recall from lesson notes and reading. However exam questions increasingly throw in a data or a graph to make the answer more specific to a situation.
These are best revised for by practise writing the “story” of a particle through a mass spectrometer, the “story” of the interstellar dust cloud which becomes a blue giant or whatever.
3) Analysis of a given scenario
These questions are the trickiest in my opinion as they throw a piece of data or a novel set up at you and you have to think on your feet a bit more. These questions are often designed to identify the A* students as they are the ones who score 5-6 marks most easily on these.
Here are two example, one GCSE and one A Level
These question include apparatus and/or graphs and tables. You must refer to the data in the graph or table. Describing the overall trend in words, identifying relevant data points on the graphs and using the numbers given on the axes i.e. quantifying the data will all score points.
In the first example the axes are not numbered so you would have to point out key features or trends. Most particles have an average speed much lower than the fastest particles forming a large hump or maxima on the graph, and that small number of particles have very high speeds forming a tail. You should fully describe the graph in other words. Do not say “the graph goes up at first and then it goes down”. The fact that a small number of particles have a slow speed is irrelevant to the question about evaporation (why?) and so you wouldn’t need to include a comment on that as it is not important information.
The second question outlines a device which student won’t be familiar with but they will have seen similar circuits before. The important information includes the stated range of temperatures and this should be linked back to values on the top graph because the graph has gridlines and numbered axes meaning you will be expected to read values from it.
The circuit is a potential divider (a fixed and a varying resistor in series) with two resistances and two voltages necessary to use the potential divider equation. Explaining how it works now becomes a more general question on explaining how a potential divider works.
Using the data to work out the voltage across the thermistor will be the route to take to score the second half of the marks.
Tackling an analysis long answer question involves more of the identifying the key physics step than some of the others. You have to be able to look at the question from a distance and spot the topic area they are asking about, recall the main points and then go back in to the detail and apply that to the scenario. You always get marks for spotting the topic area and identifying the key features/equations to use.
4) Pros and Cons
These style questions are often a straightforward comparison of two outcomes, for example should nuclear power replace fossil fuel power stations? Or they ask you to consider the wider impact of a certain choice given data and context in the question, for example is converting to an electric car a worthwhile choice?
This particular question about Europa came with some additional data showing where it is (a moon around Jupiter) and how far away it is compared to the Earth’s Moon.
These questions are best tackled as a list of pros and cons, 3 reasons with an explanation for each side and an overall judgement on the best outcome. The specific reasons you choose for or against will of course be led by the important information you have identified from the question and any key physics ideas (distance, speed and time, energy costs etc) that you know relate to the topic.
Following these tips and thinking about what type of question you have been handed will enable you to get the most out of your answer. Every question style can be tackled using the 1-6 Step method shown in the infographic, this is the basic cake, tailoring your important information and key physics topic facts to the question style is the icing on the top.