Mr C.S. Wood BSc MSc

Mr Wood is a GCSE examiner and has worked as a Grammar school head of department and science teacher for over twenty years. This wealth of experience allows him to show you how to answer questions more effectively and where to pick up those extra hidden marks.


In the context of the exam questions this means that: your answer must be based on the information given in the question. You might also be expected to give  your own knowledge and understanding but unless the information given in the question is used no marks can be given. Make sure you consider all the …

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The interval within which the true value can be expected to lie with a given level of confidence or probability. eg ‘the temperature is 20 °C ± 2 °C at a level of confidence of 95%’  The level of confidence part of this definition is just a statistical measure related to how precise (spread out) …

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Systematic error

These cause readings to differ from the true value by a consistent amount each time a measurement is made.  Sources of systematic error can include the environment methods of observation or instruments used.  Systematic errors cannot be dealt with by simple repeats. ,If a systematic error is suspected the data collection should be repeated using …

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In the context of the exam questions this means that: you need to apply your knowledge and understanding to a new situation. This command word is often used where the examiner is testing your ability to apply your existing knowledge to an unfamiliar context. You are likely to be given a scenario you are entirely …

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Sketch graph

A line graph, not necessarily on a grid, that shows the general shape of the relationship between two variables.  It will not have any points plotted and although the axes should be labelled they may not be scaled. 


In the context of the exam questions this means that: you need to draw approximately. Just use very simple lines, shapes and labels to represent the parts of what you are trying to show in your sketch. You don’t need to be an artist to gain full marks.


In the context of the exam questions this means that: you need to provide structured evidence to reach a conclusion. To do this you need to build up the logic of what you are saying step by step.  Each step in what you say should follow on logically from the previous step. Especially if it …

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This is the smallest change in the quantity being measured (input) of a measuring instrument that gives a perceptible change in the reading.  This is an important consideration in microscopy. A high resolution image can be magnified to show fine details more clearly. Magnifying a low resolution image shows a larger version of the same …

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