IGCSE Physics / Exam technique
Describing a practical method for full marks
Edexcel International GCSE Physics (4PH1), chapter 30: Exam technique, specification point 1.22, 3.19, 5.14P. Free lesson.
Read the revision notes · IGCSE Physics past papers
A full practical method names the apparatus, says exactly what you change and measure, and explains how you use the readings. Clear steps, a suitable range and relevant safety details help you earn method marks.
How to investigate a spring's extension
Measure the spring before and after adding masses. Subtract the original length from the new length to find its extension.
How to measure specific heat capacity
Measure the energy transferred to a known mass and the temperature rise. These values let you calculate specific heat capacity.
How to make method steps specific
Say what you do, how you do it and what you use. Vague phrases do not describe a measurement clearly. Instead of “change the current”, say “adjust a variable resistor to change the current”. For a spring, calculate extension = new length − original length, rather than just saying “measure the length”. Instead of “measure it”, name the instrument and readings, such as reading the thermometer at the start and end.
How to find the refractive index of glass
One pair of readings can be inaccurate. Use a range of angles, measure from the normal, and use a graph. Measure a range of angles of incidence and corresponding angles of refraction. Measure each from the normal. Plot sin i against sin r. The gradient, or steepness, of the line of best fit is the refractive index.
How to measure refraction in a glass block
Record the ray's path through the block, then measure its angle from the normal.