Using cutting-edge science within the curriculum: balancing body weight
Submitted by celius on 24 September 2010
The first semester of Year 10 is dedicated to ‘the human body’; this is the first and only time the students look at the topic in depth. Over three months, I devoted all 24 biology lessons (45 minutes each) to the sub-topic of ‘homeostasis and the human body’, focusing on the Science in School article, supplemented with video clips from The Science of Fat lectures (Evans & Friedman, 2004).
I began by asking my students if they would like to try a different teaching approach, based on a folder I had prepared containing worksheets and tables. The students would work independently and in groups to develop their own portfolios of information (notes, diagrams and essays), present their results to the others and take part in class debates. The students responded enthusiastically to the idea.
Of course, when addressing the topic of obesity, one concern is how to deal sensitively with any overweight or obese students in the class. Because the teaching unit began with a fairly lengthy consideration of homeostasis and metabolism, the students were quite relaxed by the time we discussed body mass index – and of course the students’ individual data were not made public.
Below are guidelines for reproducing the teaching unit. I used it to introduce (with the students’ agreement) a different approach to biology lessons, similar to the way scientists work. It also made my students realise that basic factual knowledge is important for understanding cutting-edge research.
If you are not able to devote such a long time to the topic, you could just use small parts of the project, or individual worksheets.
1) The daily life of a student
Start the first lesson with the simple question “How are you?” Discussing the students’ answers and separating them into polite answers and honest reflections of their current state of emotions (e.g. sad, happy, tired, bored) should lead to factors that influenced their answers, for example:
Table1: Food intake and energy expenditure. Each day, record what you eat, how much you eat, what type of physical activity you do and for how long.
2) The organ systems
To address the topic of metabolism, the students need to understand the organ systems of the body and how they work together to maintain homeostasis. Over the course of the whole unit, the students should gather a portfolio of information about the diverse functions of the organ systems, working either in groups or individually, in the classroom or at home. It is important that the teacher is only the provider of materials (textbooks, websites, models, diagrams and other information about the different organ systems); the students should gather the facts by themselves. I gave my students very little guidance about which facts to collect – providing support mostly for the weaker students. Other teachers may prefer to provide more structure.
I spent 12 lessons on the first two parts of the teaching unit, after which my students had a basic understanding of the organ systems, how they depend on each other and what homeostasis is. The only teacher lecture I gave was about the central nervous system; otherwise all the topics were student-led.
3) An evaluation of food intake and activity
Referring to their data in Table 1, the students should each state a hypothesis about their own energy balance (e.g. weight loss or weight gain). They should then consider how their results can be compared quantitatively to those of their classmates – and arrive at the idea of using the body mass index (BMI).
BMI = body mass (kg)
Using the equation or an online BMI calculatorw2, each student should calculate his or her own BMI. The first of The Science of Fat holiday lectures (‘Deconstructing obesity’ by Jeffrey M Friedman) can be used to introduce some of the limitations of BMI, in particular that it does not apply equally well to everybody.
Then, using Table 2 and the data from Table 1, each student should calculate his or her energy balance each day and average the data over the week to see in which direction his or her energy balance tips. To do this, the students will need the teacher’s guidance to convert the data in Table 1 into kilojoules. There are also many websites that do the calculations or provide the necessary informationw3.
Table 2: Food intake and energy expenditure balance
At this point, metabolism at the level of the cell can be introduced using Worksheet 2. The students should use their textbooks to answer the following questions, making the connection between our own energy balance and the activities of the cells, tissues and organs.
4) Introducing the Science in School article
Even if the variation in metabolic energy expenditure were taken into account, not all the students would have an energy balance of close to 0; instead, some of them clearly consume more (or less) energy than they expend. Why? The discussion should lead to the concept of satiety: the feeling of having eaten enough.
5) Outlook of the treatment
Before oxyntomodulin can be used widely to treat obesity, further study is necessary. From Wynne & Bloom (2007), use the box about clinical drug trials (below) to show that before drugs are licensed, they go through many stages of testing to identify and minimise side effects.
The following questions may arise or could be posed:
Concluding the topic
Ask the students to write a short essay – either a creative story or a factual discussion – about the possible impact of using oxyntomodulin to treat obesity.
Finally, the students could discuss whether this type of research should be funded at all. Why? Why not? With my students, this led to a lively debate, including the point that many more people starve to death around the world than die of obesity-related problems.
By the end of the unit, the students should have understood that our organ systems depend on and influence each other, and that if one parameter is changed there will be a chain of changes elsewhere in the system. This is true of any disturbance of body homeostasis, whether overeating, starvation or even drug abuse.
New drugs must go through a series of trials, known as phases, in order to test whether they are effective and safe.
PHASE I: Early trial in a small number of usually healthy volunteers to establish a safe dose and look for potential side-effects.
PHASE II: Larger group trial of volunteers (up to 100) with the illness to be treated, to establish short-term effectiveness and safety. Both studies described in this article were early Phase II trials.
PHASE III: Large group drug trial of volunteers (up to several thousand) with the illness, over an extended period of a year or more to compare the treatment with an existing therapy or a placebo.
PHASE IV: Drug trial usually performed after a treatment has been licensed, to establish the effectiveness of the treatment when it is used more widely and to investigate long-term risks and benefits.
This process is essential to ensure that the benefit of the treatment is greater than any possible side-effects, but it means that it can take several years for a new drug to reach the public.
Table 3: Potential obesity drugs entering each phase of clinical trials in 1994-2007. Although many potential drugs are investigated, few reach the market: only two are currently licensed in the USA.
If you have used one of our science articles in your lessons, please tell us how. Contact: firstname.lastname@example.org
Wynne K, Bloom S (2007) Oxyntomodulin: a new therapy for obesity? Science in School 6: 25-29. www.scienceinschool.org/2007/issue6/oxyntomodulin
w3 – To calculate their energy intake in kJ, the students might find the search function on the Nutrition Data website helpful. See: www.nutritiondata.com
w4 – To calculate their own basal metabolic rates, the students could use the following website: www.bmi-calculator.net
w5 – A useful slideshow presentation about basal metabolic rates is available here: www.slideshare.net/Meggib/energy-expenditure-presentation-703878
w6 – To learn more about the European Molecular Biology Laboratory (EMBL), see: www.embl.org
w7 – Science on Stage is a network of local, national and international events for teachers. National Science on Stage events culminate in a European teaching festival every two years, the next one being in Copenhagen, Denmark, from 16-19 April 2011.
To learn more about clinical trials, see:
To browse all medicine-related articles in Science in School, see: www.scienceinschool.org/medicine
Friedlinde Krotscheck has taught for a total of 25 years. After qualifying as a teacher, she taught both biology and sports at secondary schools in Hamburg and Heidelberg, Germany. In 1988, she and her family moved to Texas, USA, where she taught science for six years, and organised the annual science and mathematics day at the school. After summer courses on biotechnology and gene technology, she became a biotechnology ambassador, teaching the subjects to US high-school teachers.
Returning to her old school in Heidelberg (the Internationale Gesamtschule) in 1995, Friedlinde became involved with the education activities at the European Molecular Biology Laboratoryw6, visiting the laboratory with her students and taking part in teacher-training courses. These emphasised the importance of ‘real’ science in science teaching – planning and doing experiments and understanding the process of scientific discovery.
Since moving to Austria after her retirement in 2008, Friedlinde has continued to review articles and resources for Science in School, and to chair Science on Stage Austriaw7.
When students are actively involved in their lessons, they always both enjoy and learn more. This article shows how this can be achieved using a cutting-edge science article from Science in School that can be used to cover a whole topic of the curriculum.
The work is involved and will challenge many students with mathematics, biology and discussions on health and well-being. The students must feel secure in the classroom before they begin to discuss weight issues and it may be a good idea to mention that personal issues are confidential and should not be discussed outside the room.
The issue of drugs to control weight and promote weight loss is an interesting topic and could be extended to include herbal and over-the-counter products. Students could discuss the social, commercial and ethical issues of weight-loss products and promotions. It should be a fun and interesting way of studying a topic by making it relevant to the students’ own lives.
Shelley Goodman, UK