Practical skills
Readings, uncertainties and tables
In Paper 3 you take real measurements. Record raw readings to the precision of the instrument (a metre rule to mm, a micrometer to mm). Repeat readings and average them; the absolute uncertainty is about half the range. Table headings need the quantity and unit, like . Calculated values get the same number of significant figures as the least precise raw data, or one more.
≈ 35 minGraphs and evaluation
A good graph has labelled axes with units, scales that use more than half the grid, plotted points marked clearly and a thin best-fit line with points balanced on both sides. For the gradient, use a large triangle covering at least half the line and read its corners from the line, not from data points. Compare the gradient and intercept with a theoretical equation to find constants. Evaluating means identifying the biggest sources of uncertainty and suggesting specific, practical improvements.
≈ 35 min