There are a few different graphing software packages that can make P3.1 graphing quick and "easy"... if you know how to drive the software...
Excel
NZ Grapher
LoggerPro
NZGrapher is advised for any student with a chrome-book or who does not have excel or LoggerPro.
LoggerPro no longer costs anything. It can be downloaded for Mac or PC from this site: https://www.vernier.com/downloads/logger-pro-updates/
And just in case that site stops working: here's a direct link from a google drive: save and install:
It is not recommended you even try to use google-sheets to do P3.1 graphs. In short, google-sheets is just not up to the job of making a graph with 2 lines and with error bars that may be unique to each data point.
Below are a few youtubes for each workable graphing software above.
You should check with your teacher and follow the processes they want you to follow.
Many other videos exist. Check with your teacher before following any video you find.
FYI: below is a breakdown of what is required to Achieve, get Merit or get Excellence: from the NCEA standard (version 2):
To get Achieved: you need all 4 bullet points below:
collecting data relevant to the aim based on the manipulation of the independent variable over a reasonable range and number of values
determining appropriate uncertainties in raw data
using graphical analysis, including a consideration of uncertainties, from which the equation of the relationship/value of the physics quantity can be determined
providing a conclusion that states the equation of the relationship/value of the physics quantity as determined from the graph and includes a comparison with the physics theory.
Note the requirement for "appropriate uncertainties in raw data" & "reasonable range": For a good range your largest IV divided by your smallest IV should be at least 3, if not 4 or more. Talk to your teacher about uncertainties on raw data. You also need an equation of your linear graph line that includes at at least 1 error-line and your LOBF. You also must have some comparison of your equation/relationship/value with the physics theory!
When writing your equation of your straight line transformed graph: remember, we NEVER include units in equations. The pattern will be: (whatever you have on the vertical axis) = (your gradient) x (whatever you have on the horizontal axis) + (your vertical intercept). Use symbols for each graph axis concept. Round off values a bit from the numbers in excel, logger-pro or NZgrapher.
To get Merit: you need the Achieved package above AND all 5 bullet points below:
describing the control of other variable(s) that could significantly affect the results
using techniques to improve the accuracy of measurements
determining uncertainties in one of the variables expressed in the graphical analysis
graphical analysis which expresses the uncertainty in the relationship consistent with the uncertainty in the data
providing a conclusion that makes a quantitative comparison between the physics theory and the relationship/quantity obtained from the experimental data which includes consideration of uncertainties.
Notes
You need the essential control (or controls) that would have changed your DV measurements.
Many confuse controls for accuracy improvement techniques - so be careful.
You also need at least 1 correct set of error-bars on your linear graph.
Your equation of your LOBF will need to include uncertainties of your gradient (and intercept).
Your comparison to the physics theory should use your uncertainties from your equation - showing your calculated work. You need to show you understand uncertainties in this comparison to get Merit.
For Excellence: usually only from your discussion and only if you have Achieved & Merit parts above:
You need at least 2 parts done well, or 3 parts done "almost well".
the other variable(s) that could have changed and significantly affected the results, and how they could have changed the results
the limitations to the theory’s applicability both in the practical situation and/or at extreme values of the independent variable
any unexpected outcomes of the processing of the results and a suggestion of how they could have been caused and the effect they had on the validity of the conclusion.
Notes:
the fully explaining the controls that could have significantly changed your results includes explaining how your DV measurements would have changed, how your graph points would have changed, and how your gradient or intercept of LOBF would have changed. Use sketches of graphs whenever possible to help make your point clear.
When discussion limitations of the gear vs the situation you're trying to model: come up with at least 3 fully explained similarities and at least 3 fully explained differences. Use diagrams whenever possible.
When trying to explain how the theory breaks down at extreme IV values, remember to explain the physics of the situation and how that affects the measurement of the DV and if the square, square-root, inverse or inverse-square relationship changes with extreme IV values.
For "unexpected outcomes" that usually is about explaining in detail why you got a gradient (with uncertainty taken into account) that is not what you expected. An intercept close to zero or that includes zero in the span of uncertainties is not worthy of an excellence-explanation if you expected a zero intercept.
Finally - here is a summary of the most common errors or omissions made by L3 students in their experiment report that cause them to miss out on E or M or even fail!