Learn about bats -- a diverse group of flying mammals that humans often associate with folklore, legends, ghost stories, and scary tales. But we have more in common with bats than we think -- these tiny mammals are socially intelligent and can have a rich social structure and means of communication with each other. Bats are not only fascinating, but they are also quite beneficial to our environment and play an important role in the habitats we share with them. These animals are in need of our help now more than ever as they face population declines and serious problems, most of which originate from humans.  

Learn about where diseases come from. How are they spread? This episode examines a variety of emerging wildlife diseases, with an emphasis on the One Health concept. While some disease outbreaks may be “natural”, human behaviors and influences are adding additional pressure on wildlife and the landscape, and in the end, all of us – humans, wildlife, and the environment – are affected. Learn more about the field of emerging wildlife diseases and the continually evolving research on what those diseases tell us.  

This lesson describes the major components and functions of the immune system and the role of engineers in keeping the body healthy (e.g., vaccinations and antibiotics, among other things). This lesson also discusses how an astronaut's immune system is suppressed during spaceflight due to stress and other environmental factors.

Students learn about water poverty and how water engineers can develop appropriate solutions to a problem that is plaguing nearly a sixth of the world's population. Students follow the engineering design process to design a gravity-fed water system. They choose between different system parameters such as pipe sizes, elevation differentials between entry and exit pipes, pipe lengths and tube locations to find a design that provides the maximum flow and minimum water turbidity (cloudiness) at the point of use. In this activity, students play the role of water engineers by designing and building model gravity-fed water systems, learning the key elements necessary for viable projects that help improve the lives people in developing communities.

In this activity on page 1 of the PDF, learners compare the relative sizes of biological objects (like DNA and bacteria) that can't be seen by the naked eye. Learners will be surprised to discover the range of sizes in the microscopic world. This activity can be followed up with a second activity, "What's in a microbe?", located on page 3 in the same resource.

Student teams practice water quality analysis through turbidity measurement and coliform bacteria counts. They use information about water treatment processes to design prototype small-scale water treatment systems and test the influent (incoming) and effluent (outgoing) water to assess how well their prototypes produce safe water to prevent water-borne illnesses.

Students simulate the spread of a virus such as HIV through a population by "sharing" (but not drinking) the water in a plastic cup with several classmates. Although invisible, the water in a few of the cups has already be tainted with the "virus" (sodium carbonate). After all the students have shared their liquids, the contents of the cups are tested for the virus with phenolphthalein, a chemical that causes a striking color change in the presence of sodium carbonate. Students then set about trying to determine which of their classmates were the ones originally infected with the virus.

Students learn how viruses invade host cells and hijack the hosts' cell-reproduction mechanisms in order to make new viruses, which can in turn attack additional host cells. Students also learn how the immune system responds to a viral invasion, eventually defeating the viruses -- if all goes well. Finally, they consider the special case of HIV, in which the virus' host cell is a key component of the immune system itself, severely crippling it and ultimately leading to AIDS. The associated activity, Tracking a Virus, sets the stage for this lesson with a dramatic simulation that allows students to see for themselves how quickly a virus can spread through a population, and then challenges students to determine who the initial bearers of the virus were.