1. 1 Faculty of Applied Sciences TULO / MSc Science Education and Communication Web chemistry: Sweeteners Sec. education advanced level Science on Stage, Grenoble, April 5 th 2007 Aonne Kerkstra -Teacher at ISW in Naaldwijk -Specialist in chem. education

2. 2 Developing team (2004 – 2006) Teachers Lovina Hofmeyer Sylvia Lipman John Hukom Experts (University of Amsterdam) Nataša Brouwer, senior consultant for science education Laurens Hessels, student-assistant Diederik Slob, site tool en graphical design Jan van Maarseveen, associate professor Hens Borkent, Molecule Model Maker tools (Radboud University Nijmegen)

3. 3 Chemistry between context and concept Appealing context (Sweeteners is part of daily live) Basic concepts All matter consist of particles (Sweeteners consist of bio-organic molecules) Micro-macro concept: relationship between structure and property (taste)

4. 4 Web chemistry: Sweeteners Homepage Introduction Sweeteners Stereochemistry Synthesis of Aspartame Molecular structure en taste Further investigation Teachers manual

5. 5 1 Sweeteners Key questions What is the difference in sweetness between natural, extensive and intensive sweeteners? To which chemical compounds do sweeteners belong? How much sweeter than sugar is aspartame? Structure web page Introduction Explanation Information via links Activity Checkpoint 1

6. 6 2 Stereochemistry Key questions How can you present structural formulas? What does the 3D model of aspartame look like? When do we call a carbon atom asymmetric? What are the conditions for optical isomerism? How can you measure optical activity? Structure web page Introduction Explanation Assignments with 3D models Questions with the molecule model maker Further information via links Activity Checkpoint 2

7. 7 3 Synthesis of aspartame Key questions What are the building blocks of aspartame? What about the stereochemistry of the building blocks of aspartame? How do you recognize the L- or D-configuration in amino acids? How many and which stereo isomers does aspartame have? Which reactants are used for the synthesis of aspartame? What is the role van the enzyme in this synthesis? How do you investigate the synthesis of aspartame? Structure web page Introduction Explanation Assignments with explanation More information via links Questions Activity Checkpoint 3

8. 8 4 Molecular structure and taste Key questions Hoe does taste transfer work? What is a papilla? Which type of building blocks are used in the taste receptor? Which model can explain the operation of the sweet receptor? Which non-covalent interactions are important? How come the enantiomers of aspartame taste different? Structure web page Introduction Explanation with exercises Assignments with explanation Activity Checkpoint 4 Interaction with biology

9. 9 5 Further investigation How do the different taste receptors work? Explain what the R- and S- configurations are? Aspartame investigation in several light soft drinks. Design a new sweetener. Investigate the stability of aspartame. What happens to aspartame once it is ingested? Aspartame often gets negative publicity. Design a concept map of all types of isomers. Design your own soft drink. Student’s own idea.

10. 10 Chemical ideas and skills 1 Well knownNew to learn H-bond between polar molecules Van der Waals bond between Non-polar molecules (Polar) atom bond Ion bond Peptide bond Non-covalent interactions H-bond, interaction between polar groups in a molecule Van der Waals bond, interaction between non-polar groups in a molecule Ion bond, interaction between positive and negative ions in a molecule Structural formulas en nomenclature of: Alkanes Alcohols Carbon acids Esters Amines Amino acids Dipeptides Enzymes as a stereo specific catalyst

11. 11 Chemical ideas and skills 2 Well knownNew to learn Structure isomers (constitutional isomers) Stereo isomers Chiral molecules (asymm. C-atom) Optical activity Enantiomers Diastereoisomers General ICT skillsSpecific ICT skills E-learning 3D modeling Communication tool links for further information

12. 12 E-learning in Web chemistry: Sweeteners Question How does the navigation support the students to get the answers to the key questions? Navigation 4 chemical units several list pages Questions (a banc) Resources Concepts Dictionary OC Site map

13. 13 E-learning in Web chemistry: Sweeteners Question Which e-learning activities take place (beside reading)? Activities using animations making digital questions (feed back) investigating 3D models

14. 14 E-learning in Web chemistry: Sweeteners Question Which digital tools are used? Tools Java applets with 3D models (Jmol) Molecule Model Builders,also in combination with the assignments Digital questions in Hot potatoes Internet external links Resources (further information) Search engine in the Dictionary OC Web-log (open assignments)  computer tool  information resource  feed back

15. 15 E-learning in Web chemistry: Sweeteners Question What is the additional teachers material? How do the teachers communicate with each other? Teachers website Digital teachers material: Didactic handbook Experiments: materials, outcomes, tips Publish Students work (assignments “open projects”) Best practices (intern) Tips & tricks Share materials (intern) Give suggestions for improvements web-log Contextchemie

16. 16 http://www.contextchemie.nl/en Further information of contact a.kerkstra@tudelft.nl