In an early post, I mentioned the arrival of the Teacher Support Material for the new IB Biology guide and I would like to focus on the processing and presentation of data for this blog.
I, like other Biology teachers have been continually frustrated by the diverse interpretations of IA samples that I have, in the past, mailed off. After one report, I decided the best way to understand the moderation process, was to become a moderator. That year, I confidently submitted my sample, only to be frustrated once again. This left me feeling efforts to conform and understand the requirements to be a futile process.
So here are some of the main points I have gleamed from what has been published in the new Teacher Support Material, for the new syllabus. And I would like to stress that this are not just guidelines, but standards that we are promised, will be adhered to by the moderators of the new Internal Assessments.
- SI units should be used where possible, though it may be appropriate for minutes rather than seconds in some instances to be used etc etc etc. Inches or cups should not be used
- Tables and graphs should have detailed titles ( I tell my students to think of a title to be more of a descriptive sentence, in the hope they do not abbreviate)
- Independent variables should be in first column of a data table, decimal places should be consistent throughout, AND processed data should be to same level of accuracy as raw, etc etc etc.
- In terms of error, the advice follows what one would expect and I would like to emphasis that students citing making a mistake as an error, is not acceptable.
I would like to draw attention to two points that I feel give a different emphasis from what has gone before.
- There is a clear acknowledgement that 3 trials are permitted for a measurement (lower limit for measurements is 5). I believe this is a move away from the 5 trials which had been requested in the past (though I acknowledge it was not religiously adhered to).
- The bigger discussion point is the stipulation that points on a graph should now be joined together and a line of best fit should not be used. The argument being, there are too few data points to legitimize a line of best fit. It has generated a lot of interesting discussion in various places including social media sites, the OCC being one such place (and I encourage you to go read it there). The support material does go on to say a line of best fit can be used if reference is made to literature values.
The section on Data presentation, not only recommends what students should do, it represents the standards that moderators will look to when moderating my sample and I welcome it. One argument I repeatedly hear when discussing lab work at a workshop or in a room with other science teachers, is that this is not how papers are written in journals. Its always left me perplexed. I am not teaching students to write reports to be submitted to a journal. I am teaching them to develop their understanding of scientific methodology. For me, a set of standards that allows students to demonstrate an understanding of variables and how to manipulate and control them in a detailed method, how to present and process data to sufficiently draw conclusions and how to analyse their data to take into account variation, seems totally sufficient and appropriate. I remain confident that when they move on to further education, the approach they use will be refined.
You will, I presume have you own opinion on whether a line of best fit or a graph that connects the points is more appropriate, and I hope you join the discussion on the OCC.
I personally feel that providing guidelines that allows everyone to “sing from the same hymn sheet” is a positive step in the right direction.