Investigate four factors that may affect the strength for electromagnets: the number of turns, the size of the current, the nature of the current (a.c. or d.c.) and the distance between the sensor and the magnet.

Review of essay

Rating: 4 star(s)

Response to the question

The candidate has carried out an experiment to investigate how four factors affect the strength of the magnetic field of an electromagnet. They have successfully answered the question, but there is still a lot of room to develop their answer further, for example comparing their results to formulae or explaining the physics behind the phenomenon. All their analysis needs to be written up in their conclusion, rather than a vague statement that three of the factors had 'an effect'. Additionally, they have used different settings for each experiment - for example they changed the number of turns on the magnet between experiments, which makes it harder to compare results. Also, they have failed to use the necessary equipment to be able to thoroughly analyse their results - an ammeter should be available within school for them to use, and is essential for analysing the results when they investigated the effect of changing the current. Despite this, they have still carried out the experiments well with consistent results, and used these to answer to original question.

Level of analysis

The candidate has, where possible, analysed their results fairly well. They have drawn several graphs, calculated lines of best fit, and then described (albeit briefly) what these graphs show. However, they could have improved their analysis by drawing error bars on the graphs, showing calculations for identifying any anomalous results (every though there doesn't appear to be any, it's still good to check, and may be essential to gain marks), and describing the relationships between the variables and the strength of the magnetic field - for example describing it as 'inversely proportional'.

Quality of writing

The candidate has fairly good spelling, punctuation, and grammar. However, they have not stuck to convention in places, for example using the past tense 'I used' in the method section, when 'I will use' is more conventional. Their descriptions of the method are very good, and could easily be followed by someone who had not seen them carry out the experiment. They have also included a diagram. However, the sections of the report need to be more clearly headed - with bold, underlined test for clarity and ease of reading.
Overall, the report is readable and does its purpose, but could be quickly and easily improved by changing the presentation slightly.