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This interrupted case study examines basic concepts of chemical bonding by telling the story of "Madison," a young girl eager to learn how her hair can transition from natural curls to straight, smooth tresses. The case can be used to teach or review the major categories of bonds (ionic, covalent and hydrogen), major macromolecules of life, and hydrolytic and dehydration reactions. It also explores how chemical relaxers and heat through blow drying and flat-ironing can change the nature of straight, wavy and curly hair through the disruption of protein shape. Students will thus learn what it means when a protein has become denatured and how various variables such as pH, heat and salts can lead to the unraveling of the three-dimensional shape of proteins. This case is suitable for an AP high school course, or for an introductory biology or chemistry course for majors or non-majors. This activity can also be used as a review of basic biology and chemistry for students in an upper-level biochemistry course.

Iona Twaddell looks at the science of the waterborne disease cholera There are an estimated 3-5 million cases of cholera, a disease caused by the bacterium Vibrio cholera, each year. It is passed on through drinking water that has been contaminated with faeces from someone infected with the bacteria. Cholera causes vomiting and diarrhoea, leading to severe dehydration.

Every year during the foodless winter months, bears enter their den and lapse into a state of extended dormancy and slumber (called hibernation). For the next 130+ consecutive days they do not drink, eat, defecate, or urinate. Rarely do they die from starvation, dehydration, or poisoning from waste buildup while hibernating. How do bears prepare for this period of starvation coupled with significant weight loss? Bears are not only the champions of winter rest, but are also the undisputed champions of non-stop summer eating. They are constantly on the move during late spring and all summer long into late autumn oftentimes covering great distances over diverse habitats in their incessant search for locally and seasonally available food. In this case study, students learn the basics about bear denning, hibernation energetics, the differences in size of bear home ranges, and the nutritional landscape they must navigate to prepare for the long months of winter inactivity and caloric deprivation. The case is suitable for a wide audience, including majors or non-majors in lower- or upper-level undergraduate courses in environmental science, ecology, biology, or wildlife science.