Microscopes, Root Nodules, and a Five-Year-Old Who Knew More Than We Expected - The Roy lab at the Tennessee State Fair 2026
- 5 days ago
- 5 min read
Updated: 10 hours ago
By Sonali Roy
This year, my lab and I volunteered at the Tennessee State Fair. Our group included graduate student Hyndavi Yammanuru, postdoctoral researcher Rajni Parmar, and me. This was our third time volunteering at the fair.
The Tennessee State Fair is held with the Wilson County Fair in Lebanon, Tennessee, and usually sees approximately 800,000 visitors each year. As a state land-grant university, Tennessee State University has a booth in the 4-H Pavilion. The people who stop at our table are usually children, university alumni, and adults whose children attend one of Tennessee’s state universities. Others are simply trying to escape the heat. And honestly, who can blame them? At least it was not raining or thunderstorming this year, which would have been terrible. During the hot and humid Tennessee summer, being inside an air-conditioned pavilion is truly a godsend.
In previous years, we thought of our role mainly as promoting TSU courses and the many extension activities taking place across the university. We have also supported other faculty members and distributed flyers we made explaining gene editing. This year, however, we decided to try something different: short, hands-on activities for fairgoers related to our research on legume-microbe symboisis.
After three years of using principles of backward design in my classroom, I thought about, "What do WE want people to learn?"
We came up with three lessons we wanted the audience to leave with.
(1) Legumes are good for the planet because they can essentially make their own fertilizer.
(2) Bacteria are not always bad. Some bacteria help us and, in this case, they help legumes obtain nutrition.
(3) Scientists can manipulate these processes at the level of genes. (We did not include a gene-editing activity this time, but we hope to add one next year if we can devise a simple way to show visitors that the DNA of plants can be changed.)
For this year, we focused on the first two learning outcomes.
And of course I also wanted to think about ways to measure what they learned.
"How would we know whether they had actually learned something?"
Of course, we also had giveaways to incentivize participation, which helped attract people to the table. A colleague (shoutout to Dr. Brione Lockett!) had generously supplied us with many TSU-branded items, including lunch boxes, cute cutting boards, and thermal lunch bags. We did need help transporting everything from the parking lot to the pavilion, but thankfully, plenty of golf carts were being driven around the fairgrounds, and I was even able to drive one thanks to a generous food truck vendor.
The irresistible power of a microscope
One of our first and most useful observations was that children became immediately interested in our table as soon as they saw a microscope! It was a table compound microscope, but that was enough to draw them in. Note to self: always have an activity involving a microscope.
Our first activity began with a sheet of paper divided into two columns: “Do you think all microbes are bad?” and “Do you think some microbes are helpful to us?” Before showing participants anything, we asked them to mark what they thought.
One child told us, “I only know that bacteria make us to stay in the bathroom for too long.” Fair enough. Haha!
Next, we showed everyone some plant roots. This produced an unexpectedly enthusiastic response. One person said, “It looks like straw!” Another girl with blonde hair looked at the roots and said, “It looks like my hair!” We pointed out the tiny nodules along the roots and explained that these are the places where beneficial bacteria live. The bacteria help the plants obtain nutrients, and the plants provide sugars to the bacteria in exchange. We then let participants look at the nodules under the microscope. We also showed them blue GUS-stained roots and nodules to demonstrate that scientists can stain plant tissues and structures to make them visible.
To find out whether the children had understood what they saw, we asked them to draw it. Some drew perfect little ovals along straight lines, indicating that they had recognized the nodules growing along the roots. (Note: In hindsight, we should have phrased the question more specifically. We could have asked, “Where do you think friendly bacteria live?” and then noted whether the children drew nodules on the roots. That would have provided a clearer measure of what they had learned.)
This activity conveyed two of our central messages: friendly bacteria exist, and they can help plants obtain nutrition.
Gamification of Plant Identification
For our second activity, we displayed corn, quinoa, peanuts, white and black chickpeas, and kidney beans in labeled square Petri dishes.
First, we asked visitors whether they could recognize the different seeds. Some immediately identified the kidney beans by saying, “That’s in chili!” When one child could not recognize quinoa, his mother reminded him, “You have seen it more swollen after it is steamed.”
One hundred percent of participants could recognize the peanuts and corn. Chickpeas were much more difficult. This may be cultural. (When I mentioned hummus, some of the children still did not know what I meant, so I will have to think of a more relatable chickpea-based food for next year.)
After identifying the seeds, we asked participants another question: “Can you rank these plants according to how much food they need to grow?”
Honestly, we would have accepted any order among the legumes, provided that corn and quinoa were placed first and second, followed by the legumes. The specific order we used as our answer was corn, quinoa, kidney bean, chickpea and peanut.
It was fascinating to follow people's ranking logic.
One girl decided that chickpeas probably needed the most food because the seeds were the largest, while quinoa must need the least because its seeds were the smallest. That was actually very good reasoning.
Another participant concluded that corn must need the least because it is grown so widely in the United States. Therefore, it must be the cheapest crop for farmers to grow. Again, this was great logic, although the conclusion was incorrect.
Then a child who appeared to be approximately five years old placed every crop in the exact correct order - 100 percent correct!! His parents were surprised. He, however, was completely confident. I have no idea how he knew! I should have asked him to explain his reasoning, but unfortunately, I did not. (Can we pre-recruit 5-year-olds to research labs?! At least I got to high-five this legend!)
All in all, turning the lesson into a game was a lot of fun for both the participants and us. This activity again emphasized the first learning outcome that legumes are good for the planet. A mother who brought her daughter to our table also told us, “This is a good game to teach that.” I got my validation that hour!
Learning as we go
This post is partly a record of what we did, partly a reminder of what we learned, and partly a way to remember the fun we had together as a lab at the 2026 Tennessee State Fair.
We will be better prepared next year, although I seem to say that to myself every year.
But perhaps the more important lesson is that even when an outreach activity is imperfect, it is still worth trying. After all, the point of life is to live it, and the point of gaining knowledge is to share it.
Editor’s note: This post was edited for grammar and flow with assistance from artificial intelligence (AI). All experiences, observations, and ideas are the author’s own.
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