Science on Tap: Swirl, see, sniff, sip, and savor. . .some soil samples!
February 12, 2026
Have you ever soiled your underwear? Ha! Probably not with the soil you're thinking of. But this question opened a conversation about the living world beneath our feet, led by Summer Thomas of the Virginia Soil Health Coalition and Caroline Wolcott, a Virginia Tech Ph.D. student in the School of Plant and Environmental Sciences. Through clear explanations and hands-on demonstrations, they showed us what soil function looks like, the many different tools they use, and how anyone can assess soil health. . .yes, even using underwear.
Wolcott led a hands-on demonstration using an apple to represent the Earth. She carefully cut away sections to show how much of the planet is covered by water, deserts, ice, parking lots, cities, and other areas unsuitable for farming, leaving only a small sliver of peel to illustrate the limited land available for crops. As she worked, she explained how this small fraction of farmable land must support a growing population and that soil health plays a critical role in sustaining it. Through this visual exercise, Wolcott highlighted the scarcity of crop land, the impact of human activities on the soil, and the importance of caring for the land that we rely on for food.
Wolcott and Thomas then showed participants the tools they use to study soil. Wolcott held up a single steel ring and explained that embedding it in the ground and adding water to it allows her to measure how quickly the infiltrates into the soil. She noted that heavy equipment and site disturbances affect soil’s ability to absorb water. She also demonstrated an auger, a tool used to remove a soil core and reveal the soil profile, giving participants a closer look at soil structure. Thomas used a soil probe to demonstrate taking soil samples at different depths and described other tools used in soil research, including GIS software for mapping and experimental design, an artificial rainfall simulator to measure runoff and nutrients like phosphorus, nitrogen, and potassium, and drones that capture hundreds of images to model and track grass growth in cattle pastures. The images provide information about what's happening below the surface. Together, the demonstrations highlighted both hands-on and high-tech ways that scientists study and care for soil.
Wolcott and Thomas ended the night with a “Soil Cicerones” activity that included a soil flight to allow audience members to explore soil health in an interactive and engaging way. They guided participants through the five S’s: swirl, see, sniff, sip, and savor. Each soil sample had been collected from an area under a different management system, and participants observed key characteristics before guessing which system matched each soil. Thomas demonstrated “swirl” using intact versus crushed Cheerios and adding milk to each to show how soil structure affects the movement of water, roots, and air.
Participants rotated through sensory and hands-on demonstrations to assess soil health more closely and apply what they were learning. They compared soil colors to understand differences in organic matter, noted the presence of roots as evidence of improved soil function, and broke soil samples apart to smell for earthy versus unpleasant odors. The group also tested soil aggregate stability by submerging soil in water and observing how well it held together. The activity concluded with the memorable “soil your undies” challenge: Burying a pair of all-cotton underpants in your soil for 60 days can provide a simple, visual indicator of biological activity. If the fabric is largely decomposed when dug up, it may suggest more active soil life, whereas more intact fabric could indicate lower levels of biological activity.
Participants enjoyed discussing their guesses, with campus soil standing out as a memorable example. Several participants identified the highly disturbed soil from the Virginia Tech campus that had been included in the flight, describing it as “dusty and degraded.” One participant even found a coin in the soil sample, adding to the fun of the activity.
The evening wrapped up with an introduction of the 4theSoil campaign and a discussion of how humans can play a role in improving soil health in everyday life. Participants learned that keeping soil covered, minimizing disturbance, maximizing living roots, and energizing soil with diversity can help stimulate biological activity and strengthen overall soil function. This final takeaway connected the hands-on experiences to simple actions participants could use to help the soil in their own spaces.
Science on Tap is a free monthly event sponsored and supported by the Center for Communicating Science and by Virginia Tech's chapter of Sigma Xi. Curious about viruses, pandemics, and organoids? Join us at 5:30 p.m. on February 26th as Hannah Brown shares her fascinating research with her Science on Tap presentation "Tiny organs and tricky viruses"!
By Lauren Tucker, Center for Communicating Science graduate assistant