Skill 1 & 2
1. Spend about 3-5 min reading question. Take note of important points and variables to be changed and measured.
2. First task –> to draw tables and columns with headings, units and number of d.p or s.f (written in pencil above the column [area outside the table]). Each data set carried out from the experiment must be transferred to the table. But do not do calculation at this point!
3. Collect and record all data from experiment. Process [do calculation to obtain value for other columns in the table] data only after ALL measurements are taken.
4. All students should have sharp pencil, clear ball point pen (do not use to plot graph), calculator and 30 cm long transparent ruler to plot graph.
5. Gradients need NOT have units unless question specifically ask for
it. Gradient computed to be 3 s.f.
6. If x-axis (horizontal axis) starts from zero, y intercept can be read off from graph and to have same accuracy as y values. Y intercept to have same units as y values.
7. If x-axis does not start from zero, y intercept to be computed from
y=mx+c. Y intercept to be 3 s.f in this case and to have same units as y
8. Graph to be at least 50 percent of graph paper.
9. Size of 1 cross (data point) to be size of 1 small graph paper grid.
10. Line of best fit to draw graph (refer to workbook for explanation of line of best fit)
11. Need NOT start x and y axes from zero unless specified in question.
12. Appropriate scale – Do not use 2 cm to represent 3 units, 6 units or 7 units and their multiples.
13. Label x and y axes with units
14. Measured values to follow accuracy of instrument (eg. length measurements to record to 1 decimal place)
15. Computed values/processed data are written to 3 s.f.
16. Identify 2 key sources of errors if asked in question (common errors in practical)
17. ALWAYS calculate the y-intercept in order to conclude the relationship. Unit must be present for the y-intercept value. Eg. a varies linearly with b OR a is linearly related to b #if y-intercept is non zero
Terms to use: linearly (straight line that doesn’t pass through the origin) , non-linearly related (curve), directly proportional (cut through origin).
18. Setting up and data collecting should not take more than 20 minutes.
19. Raise hand to alert invigilator to mark intermediate step if specified in question
20. At least 5 set of data points in the table unless question specifies otherwise.
Visual learner –> Link 1, Link 2
How to plot a graph –> Link 1