2.3 Carbohydrates and Lipids

Evaluating claims—health claims made about lipids in diets need to be assessed. (5.2) (IBO; 39)

This NOS links nicely to to syllabus knowledge statements:

  1. Unsaturated fatty acids can be cis or trans isomers. (IBO; 39)

  2. Application: Scientific evidence for health risks of trans fats and saturated fatty acids. (IBO; 39)

  3. Application: Evaluation of evidence and the methods used to obtain the evidence for health claims made about lipids. (IBO; 39)

The concept of evaluating claims also lends itself to TOK.  Thus it is possible to teach necessary content, the NOS and provide TOK integration, all in the one lesson.  This is the best way, in my opinion, to incorporate the NOS (or TOK for that matter)- not as “additional content” but complementary to the learning that is already going on.

The first lesson involves covering the understandings: the molecular structure of fatty acids, the differences between saturated and unsaturated FAs and the difference between cis and trans unsaturated FAs.  This covers the content needed.  In our next lesson, the students are placed in groups and have one of the following four articles allocated to them:

We should ban Trans Fats – The Guardian

Dairy Products Don’t Cause Heart Disease– The Guardian

Are Fats Bad? – New York Times

Butter is Back – New York Times

As part of their reading, the students are asked to identify the First Order Knowledge Claims made in the article.  These are claims about knowledge within specific subject areas – for instance, Trans fats increase the risk of heart disease.

The students then share their knowledge claims on the board, using the Sustainability Compass (Compass Education). The board is divided into the four compass points (N, E, S, W), representing the four key dimensions of sustainability: NatureEconomySociety, and Well-being. This adds another layer to the discussion by having the students incorporate systems thinking – environmental effects of industrial animal farming, econmoic impacts of chronic health problems, the personal impacts of diet choices and lifestyles etc.

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The Sustainability Compass (Compass Education

The next part is, as a class, to select 3-5 of these First Order Knowledge Claims and identify the TOK concepts and vocabulary that match them best and to then develop them into Second Order Knowledge Claims.  These are the focus of TOK – claims about the nature of knowledge.  Students must be able to distinguish between first and second order claims as a central part of their TOK course. The final task is to develop the second order knowledge claims into appropriate knowledge questions (open-ended, general and about knowledge) – which are cornerstone of the TOK presentation and essay.

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Ideally, we do this in one 85-minute lesson, though if you set the reading for homework it would be possible to complete this in a shorter period.

Thanks to Camille Garewal (@CDolmont) for pictures and inspiration for this post.


IBO. Biology Guide: First Assessment 2016. IBO, 2014.

“Compass and Accelerator Tools.” Compass Education, AtKisson, 10 Aug. 2017, http://www.compasseducation.org/resources/compass-and-accelerator/.

IBO. Theory of Knowledge Guide: First Assessment 2015. IBO, 2013.

“Sustainability Compass.” Accelerator Pro, AtKisson, 2017, atkisson.com/tools/.


4.3 Carbon Cycling and 4.4 Climate Change

Making accurate, quantitative measurements—it is important to obtain reliable data on the concentration of carbon dioxide and methane in the atmosphere. (IBO, 63) 

Assessing claims—assessment of the claims that human activities are producing climate change. (IBO, 65)

Climate change continues to be the subject of much debate in certain sections of the media and the world, despite the proliferation of evidence that supports both rapid climate change and the human role in driving it.  As these two NOS states, and as we learn in TOK, claims must be assessed and their evidence evaluated to determine their truth.

The best place to begin is to explore the website for the Intergovernmental Panel on Climate Change (IPCC), the global body that synthesises the climate research and produces reports at intervals of 5-6 years.  The Fifth Assessment Report was published between September 2013 and November 2014. The reports are provided in PDF and can be daunting!  However, the Summary for Policymakers  provides a nice overview of the main results of the review, including details on greenhouse gas emissions, temperature change, ocean acidification, snow and ice cover and changes in animal and plant behaviour and life-cycles.

A good activity for the students is adapted from Stephen Taylor’s page at i-biology.  Students can access a range of different databases from the CDIAC to examine carbon emissions.  I have the students collect data for both the last 5 years and for the entirety of the database they have chosen.  The longer the database, the more clearly the trend is displayed.  Students can then practice their graphing and analysis skills using spreadsheets.  With the new IA Guidelines allowing for database analysis, this could be a good starting point for an investigation.

Student Task Sheet
Student Task Sheet

We finished our sequence of classes with a great discussion on the precautionary principle.  This is no longer explicitly required in the new syllabus but has great links to TOK and also to the idea of verifying data. We used the Visible Thinking Truth Routine – Claim, Support, Question– to examine two different articles with an opposing view of the PP. We ended up debating what certainty level is required for proof in the natural sciences – a nice end to the topic.

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Biology Guide: First Assessment 2016. Cardiff: IBO, 2014. Print.

“Carbon Cycle.” BioNinja, 2017, http://www.ib.bioninja.com.au/standard-level/topic-4-ecology/43-carbon-cycling/carbon-cycle.html.