What makes nutmeg and cloves smell like Christmas, while polyurethane-based adhesive smells like, well, glue?
As we enter week four of the weekly, online, video series “Chemistry Now,” we find that placement of a double bond in the hydrocarbon side chain makes all the difference in how eugenol, found in cloves, and isoeugenol, found in nutmeg, taste and smell.
Subtle differences in bonds can also make or break efforts to create a stronger, more useful adhesive, as well as give it that pungent, acrid smell.
Finally, subtle changes in how teachers introduce scientific concepts to their students can bind those ideas in richer, more complex ways, leading to greater understanding. As has become our habit, please view the video, try the lessons, and let us know what you think.
Through the Chemistry Now series, NSTA and NBC Learn have teamed up with the National Science Foundation (NSF) to create lessons related to common, physical objects in our world and the changes they undergo every day. The series also looks at the lives and work of scientists on the frontiers of 21st century chemistry.
Spices: Maureen Shaughnessy
Close-up of glue: Sam Catch
Video: “The Chemical Bond Between Cloves and Nutmeg” focuses on the variety, strengths — and placement — of chemical bonds in the structures of molecules. In a “bonding” story of another kind, NBC Learn profiles Purdue materials chemist Jon Wilker, who’s making synthetic adhesives based on the glues mussels produce underwater.
Middle school lesson: To give students a better understanding of molecular interactions through experimentation with adhesives. In this experiment, students will test three different types of tapes to see how well they hold squares made of three different materials (cardboard, plastic, magazine covers) together. This lesson encourages inquiry, understanding of the scientific process, and study of materials.
High school lesson: To demonstrate van der Waals (intermolecular) forces, viscosity, adhesion, and cohesion and their relationship to adhesives by having students conduct an experiment to test the effectiveness of three different types of glue on three different materials at room temperature and at refrigerator temperature.
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