Many colleges enter their students for the practical exam instead of doing coursework. Indeed at a recent meeting with a chief examiner, I heard that more and more students were being entered for the practical paper. In one college it had been decided that all the girls should do coursework and all the boys the practical exam!
The advantage about the practical exam is that the practical skills are assessed in one session, and does not drag out over several sessions. The downside is that some students feel more stressed.
The skills assessed are exactly the same as in coursework. There is no question about having to "Jump more hoops". Indeed the AQA takes into account the stress of the exam so that students are not disadvantaged by doing the exam compared to coursework.
The exam lasts 105 minutes. It has two questions:
Question 1 asks you to design an experiment, given a situation you are unlikely to have met before. Don't panic and don't be tempted to write lots and lots. Look carefully at the tips below. Keep it in terms of the Physics you can do in a school laboratory. You should spend about 30 minutes on this.
Question 2 is the practical part of the exam. You will have apparatus set up ready for you to start work. The Board give instructions to teachers and technicians on how the apparatus should be set up. You do NOT have to set it up yourself. You must not ask for help in using the apparatus. However if you are concerned that the apparatus itself is not working, ASK FOR HELP. Do exactly as asked. You may find the experiment rather contrived, but don't add any extra steps. (Some experiments have even had the teachers baffled as to what the point is, so if you are not sure, don't spend time worrying about it.)
You may answer the questions in either order.
In the practical exam only do what the questions ask.
· Show clearly any distances to be measured.
· Label items and add “how-to-do-it” comments (saves words in the method).
· List items not shown in the diagram (don’t draw stop-clocks, micrometers, etc).
Method (Write as if you are giving direct instructions to somebody. Keep sentences simple and as short as possible. Use numbered steps.).
· State each measurement to be taken and the equipment used to measure it. Give ranges of any measuring instruments (e.g. ammeter 0 - 100 mA).
· State the factors you will need to control and how you will do this.
· Explain how the measurements will be used to answer the question set. If appropriate do a calculation using an equation (e.g. Power = 3 V × 1.5 A = 4.5 W).
· If appropriate, sketch the graph you expect to get.
Precautions
· State any special precautions you would take to overcome any difficulties in obtaining reliable results.
Do NOT write a method; you will gain no marks for this.
Results
· Do a quick try out to check apparatus.
· Make rough measurements to work out a table.
(Headings written as QUANTITY / UNIT). Box your table in.
· Record careful measurements in the order you measure them. If possible begin with small, big and middle readings to get a good range, then add more. Do at least 5 readings. Do repeat readings.
· No fair copy needed (mistakes can be crossed out and rewritten).
· Leave apparatus set up in case you need more results later (e.g. repeats).
· Calculate extra columns for graph.
· Use easy scales.
· Label axes QUANTITY / UNIT.
· Plot points and draw best-fit line in pencil.
· Find gradient and/or intercept. Use a large rise/run.
· Write values on graph.
Conclusion (Questions will guide you and may include the following points.)
· Use your gradient and/or intercept to calculate a final result. Remember to put units into your answer for the gradient (e.g. the gradient of the voltage-current graph is the resistance in ohms).
· Consider how a change in the method might affect the outcome.
· By considering the biggest source of error, suggest how the experiment could be improved.
Criteria for awarding marks in the practical exam (AQA guidance)
The following is intended to give general guidance only.
Planning
· Identify a key factor to vary
· Explain how this factor is to be measured
· Use physics knowledge to explain how the observations will be used to
solve the problem set or to test the hypothesis posed
· Show graphically, e.g. using a circuit diagram, the practical set-up
· Identify factor(s) that need to be controlled
· Explain how these controls will be achieved
· Explain measure(s) to ensure that accuracy/precision is/are achieved
· Explain how any potential difficulties in obtaining a reliable result will be overcome
· Make a sensible estimate of the number and range of readings to be taken (A2 only)
· Perform relevant supporting calculation (A2 only) [10 MAX 8]
Implementing
· Tabulation of results: suitable headings in table
· Adequate number and range of results
· Steps taken to overcome random [systematic ] error
· Use of significant figures in both tabulated and derived data
· General quality mark, judged from scatter on graph
· Tabulation of intermediate data sets or additional calculations (A2 only) [8]
Analysing -processing data
· Axes marked correctly on graph
· Suitable scales
· Correct plotting of points
· Best-fit line or curve, suitably drawn [4]
· From graph: direct (e.g. intercept or interpolating)
· Or indirect (e.g. gradient)
· Result of numerical analysis (may be calculation set in context of question) [4]
Evaluating
· Comments about procedures or techniques
· Justification of significant figures
· Predictions about alternative outcomes, suitably justified
· Qualitative or quantitative (A2 only) discussion of proposed extension to enquiry
· Discussion of quality of graphical work/discussion of anomalous results [6]
Quality of Written Communication
· Good grammar, spelling and punctuation
· Correct use of specialist terms [2]
Total = 30 marks