Secret of Sweetness

Scenario information

Subject: Biology

Grade: 1st grade, high school
Level of implementation complexity: medium
Correlations and interdisciplinarity:


  • Personal and social development
  • Health, Safety and Environmental Protection
  • Civil education
  • Use of information and communication technologies

Key Words: cellulose, dietary fiber, glycemic index, natural fibers, relative sweetness of matter, diabetes mellitus, synthetic fibers, sweeteners, carbohydrates

Learning outcomes:

  • compare the advantages and disadvantages of natural and artificial sweeteners (A)
  • distinguish between carbohydrates according to relative sweetness (A)
  • assess the quality of personal eating habits (A, B)
  • describe the classification and role of carbohydrates (B)
  • explain the wide application of cellulose as a representative of polysaccharides (C)
  • explain the importance of controlling blood sugar concentration as a way of early detection of diabetes symptoms and its prevention (D, E)

*In parentheses, there are letters indicating individual teaching scenario activities, the implementation of which contributes to achieving the respective outcomes.

Tips and instructions for using digital teaching tools you can find at e-Laboratory (only in Croatian).

Activity description

A What is sweeter?

Prepare several carbohydrate samples of different sweetness levels (fructose, glucose, sucrose, lactose, starch etc.), a few natural sweeteners such as stevia, agave syrup, maple syrup, honey etc., and a few artificial sweeteners of choice (saccharin etc.). Prepare solutions of the mentioned samples in approximately equal concentrations and a set of disposable teaspoons. Have the students try each of the offered samples and then provide the results of their subjective experience involving the sweetness level of each sweetener in the tool Mentimeter. Have the students present their views and discuss them. Refer them to the e-school chemistry web site (digital content in Croatian language involving chemistry for students and teachers) to study the meaning of the concept related to relative sweetness of substances. In the second slide in the Mentimeter tool, introduce the known values related to relative sweetness of the tested substances and have the students make a comparison with their subjective impressions.

Point out that sucrose is usually set as the standard of sweetness, and you can have them match its sweetness to other sweeteners. Note that sucrose is almost ubiquitous in food products. It often appears as “hidden sugar” in foods such as canned fruit, fruit yogurt, packet soup, sauces, fitness cereals and the like. Head a discussion with the students on the importance of a limited intake of such foods, especially those foods that we do not experience as “sweet”.
Students can create an infographic on hidden sugar in food in the Piktochart tool.

Support procedures

For the visually impaired students, prepare an audio recording on the meaning of the concept related to relative sweetness of substances if there is no text written in Braille. For partially sighted students, it is required to adjust the font in accordance with their remaining sight. The Mentimeter activity allows these students to work in pairs so their peers can help them complete tasks by describing required actions and obtained results or by entering data, and create graphical illustrations. Depending on their needs, other students with disabilities, e.g. motor impairment students, can also work in pairs.

B Simple vs. complex

In the Padlet tool, display a few photographs downloaded from certain web sites and published under the Creative Commons license. Look for photos showing, for example, honey, cotton, starch/potatoes, fruit etc. Ask students what associations and experiences do the displayed photos evoke. Encourage students to find the link between the photos and guide them to a common conclusion involving the presence of carbohydrates on each of the photos displayed. Have them name the main carbohydrates inherent in each instance, then have them divide the named carbohydrates into simple and complex ones. Discuss with the students why we often prefer simple carbohydrates in our diet.

Refer the students to the article on the balanced diet pyramid at the Biology web page (Croatian scientific portal specializing in news and articles from the field of biology and related sciences: physiology, medicine, psychology, sociology, anthropology, nutrition, agronomy, climatology and other sciences). Divide the students into two groups, one of which represents a “healthy diet pyramid” and the other “my pyramid”, and organize a debate on the given topic. The aim of the debate is to recognize the advantages and disadvantages of the two proposed ways of a healthy diet. After the discussion, talk to the students about the benefits of the “Healthy Eating Plate”. Guide them to notice that complex carbohydrates are largely represented in such a diet and discuss the reasons for such selection.

Support procedures

In the introductory activity, students with sight impairment may taste or touch the foods shown in the photographs, or the photographs may be described to them. You may specify the main carbohydrates inherent to the instances in an assignment of associating them to a particular instance. Then, have them divide the carbohydrates into simple and complex, with a prior check whether they understand the concepts. The text on the healthy diet pyramid may be provided to the visually impaired students as an audio recording, and other students may be given questions to help them find the relevant points in the text. Students with disabilities (especially students with intellectual disabilities) should have an image of a healthy diet pyramid glued in their notebook. In the discussion, make sure peers help students with motor disturbances, vision and hearing impairments.
Students with voice, speech and language disorders are able to express themselves, but you should prepare information for them and offer short and clear questions (except for stammering, but the stammering students have days of good and bad fluency, which affects their ability to express themselves).

C Gentle like cotton, destructive as explosive

Watch the nitrocellulose test video lasting 0:07 minutes, which video shows the burning of an “unusual cotton wool”, more specifically nitrocellulose, with the students. For comparison, you can take a piece of ordinary cotton wool, the composition of which is known to the students, and demonstrate its burning. Have the students present their observations on the difference in burning involving these two substances. Describe the use of nitrocellulose, and then have the students state examples of numerous other common cellulose products, the most common organic matter on Earth, by brainstorming in the tool. Discuss with the students about the role of cellulose as a building material in plant cells, and about the role of cellulose in everyday life of humans. Guide the students to associate cellulose properties and materials according to the way we use them. Divide the students into groups with regard to ideas proposed on cellulose use and refer to them to web pages to explore the topic in depth and share the results on Yammer. By using the teaching technique “summarize and pair up to exchange”, students can make a summary of results shared in the social network and discuss the similarities and differences of their summaries in pairs.

Support procedures

The Didactic-Methodical Guidelines for Natural Sciences and Mathematics for Students with Disabilities (instructions available only in Croatian on the teaching scenario web page) specifies how to involve students in data collection and processing activities, as well as oral speech activities and in participating in the discussion. Refer students with disabilities in advance to web pages where they can find the desired data and give them questions to explore key data. You may arrange for an active speaking preparation with students with voice, speech and language disorders if they want to, but you do not have ask them to speak to the group if it is a problem for them. Encourage stammering students to active oral presentation depending on their fluency assessment. Describe to the partially sighted students the given video.

D Starvation in abundance

Provide the students with a survey incorporating a few short questions on diabetes, such as: What does the world-famous symbol of the blue circle represent? What is the amount of normal blood glucose concentration? What kind of diabetes is most common in young people? You can use Google Forms to create a poll. Analyze the survey with your students and then refer them to online diabetes diet websites like the Diabetes Diet blog (in Croatian language) to explore the frequency of diabetes in the world and in Croatia by regional representation, age and sex. Talk about the possible causes of higher prevalence of this disease in individual populations. Discuss with students the importance of identifying the symptoms and preventing diabetes with regard to its epidemic proportions assumed, and encourage students to propose ways to help a person with such illness in case of emergency. Students can share their understanding by developing an animation in Moovly on Identifying the Symptoms and Providing First Aid to Diabetic Patients. Presentation can be posted on Youtube or Facebook in order to make information on diabetes available to the wider community.

Support procedures

Make sure students know how to use Moovly and, if necessary, demonstrate how it is used. Involve students with disabilities in developing an animation in Moovly so that they suggest ideas and their peers help them during animation development. When answering the questionnaire, read the questions to the partially sighted students or provide them with an insight into the questions in advance.

E Well prepared is half done

In order to better control the blood sugar levels of diabetics, nutrition planning often takes into account the glycemic value of individual foods. Explain to students how such meal planning can help to avoid health complications, both in healthy people and in diabetics. Share the glycemic value table involving the selected foods with the students on Google Drive or project them onto a whiteboard, and have them develop an illustration shared as a traffic light in Web Whiteboard classifying foods according to their high, low and middle glycemic index. Talk to students about the importance of mixing various foods in one’s diet and controlling the amount of individual foods on the menu, both in diabetics and in healthy people.

You can teach your students to compare the glycemic index and the calorific value of the natural and artificial sweeteners we use in the diet. Encourage them to mention the disadvantages and advantages of using natural and artificial sweeteners. Students can make their own conclusions in Canva as an infographic, and publish it on the school’s web page to raise awareness of healthy lifestyle habits.

Support procedures

Encourage visually impaired students to increase their participation in activities involving discussion and expressing of opinions and previously known facts. Read the instructions to the partially sighted students or provide an insight into the instructions in advance, and plan pair work when dealing with the table of glycemic values of some foods. Conclusions may be provided to students as a supplement to their notes to use later as a repetition template.

For students who want to know more

You can suggest to the interested students to prepare and conduct a workshop on Hair and Fiber Traces in Forensic Tests for other students in the class. Students can demonstrate the production of microscope hair slides, natural (most commonly used herbal ones are cotton fibers) and synthetic fibers, and clarify the methods used by forensic specialists to distinguish between these three groups of evidence. They can explore online which hair and fiber properties are examined by microscopy and, when preparing the workshop, they can use the article entitled Alphabetical Guide through the World of Artificial Fibers  (in Croatian language) and Hair and Fiber Traces in Forensic Examinations (in Croatian language).

Additional literature, information, and links

You can find additional clarification of terms on relevant web pages

  • Google Scholar
  • Struna (Croatian vocational terminology),
  • Croatian Encyclopedia etc.

Note: Validity of all network links last established on 25th February 2017

Did you apply this teaching scenario in you class? Tell us your opinion by filling out the questionnaire in this link. (in Croatian language)

This text is licensed under Creative Commons Attribution 4.0 International. When using this text, you should refer to the text authorship in the following manner: CARNet (2017) e-Schools Teaching Scenario ˝ (enter the title of the teaching scenario) ˝,