Transcript Human Activities in the Delta

Web chemistry: Sweeteners
Sec. education advanced level
Science on Stage, Grenoble, April 5th 2007
Aonne Kerkstra
-Teacher at ISW in Naaldwijk
-Specialist in chem. education
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Faculty of Applied Sciences
TULO / MSc Science Education and Communication
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)
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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)
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Web chemistry: Sweeteners
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Homepage
Introduction Sweeteners
Stereochemistry
Synthesis of Aspartame
Molecular structure en taste
Further investigation
Teachers manual
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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
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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
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3 Synthesis of aspartame
• Key questions
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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
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Introduction
Explanation
Assignments with explanation
More information via links
Questions
Activity
Checkpoint 3
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4 Molecular structure and taste
• Key questions
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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
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• Introduction
• Explanation with exercises
• Assignments with explanation
• Activity
• Checkpoint 4
Interaction with biology
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5 Further investigation
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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.
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Chemical ideas and skills 1
Well known
New 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
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Chemical ideas and skills 2
Well known
New to learn
Structure isomers
(constitutional isomers)
Stereo isomers
 Chiral molecules (asymm. C-atom)
 Optical activity
 Enantiomers
 Diastereoisomers
General ICT skills
Specific ICT skills
 E-learning
 3D modeling
 Communication tool
 links for further information
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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
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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
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E-learning in Web chemistry: Sweeteners
• Question
• Which digital tools are used?
• Tools
 computer tool
 information resource
 feed back
• 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)
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E-learning in Web chemistry: Sweeteners
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Question
• What is the additional teachers material?
• How do the teachers communicate with each other?
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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
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http://www.contextchemie.nl/en
Further information of contact
[email protected]
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