The Science of Track Cycling

Action shot of bikes on the Dicklane Velodrome track.

Credit: T.L Lawrence

By Beena Meena

It was a beautiful fall morning and I was biking with my friend Chanel on our way back from an arduous 40-mile ride when we passed the scenic Sumner Park in East Point. Chanel Zeisel started regular bike racing in 2015 and finished her first USA cycling track race in Los Angeles two years later. We entered the park, home to an oval-shaped track; it was similar to a running track but its platform was sloped. As an active road cycling athlete myself, I had heard of track cycling races, but this was the first time I had seen a velodrome: a superelevated, oval-shaped track used in the sport of track cycling.

Georgia’s only Velodrome

The only velodrome in Georgia and one of the only 22 active velodromes in the United States, the Dicklane Velodrome (DLV) was constructed in 1974 as an initiative led by a group of locals who had visited the Munich Olympics and were inspired by the sport of track cycling. One of a kind, the East Point velodrome loops a grassy island, home to an oak tree and a running creek, that provides both cyclists and spectators with a view of natural serenity that contrasts with the adrenaline rush and the thrill of the races. 

The track is  ⅕ mile with a maximum angle of 36 degrees on the banks. My eyes fell on the steep embankments, as we pulled our bikes onto the track. “How on earth can you ride a bike on such a steep surface?!” I gasped with the frightening image of a cyclist sliding down in my head. “Just start from the apron (the flat surface on the base of the track) and move on to the higher elevations gradually after each lap,” Chanel said to me from the top of the ramp, flying by at 40 miles an hour on her bike. “And don’t touch your brakes,” she yelled. Nervously, I clipped in on the pedals of my road bike and decided to stay on the apron.  However, as I gained speed, my bike started to lean towards the ground while bending along the track curves, and I found myself jumping over to the blue strip, the innermost, and the shallowest side of the banks. As I gained more speed, I would jump over to the steeper side. Soon I was riding in the same lane as Chanel along the highest elevation and steepest curves. “It’s all physics, you know,” said Chanel.

It was true, and the laws of physics are what kept me riding on the banks rather than playing out the collision I had imagined when first seeing the DLV. When we bike in a straight line the main forces involved are the gravitational pull by the earth, which is counteracted by the upward normal push by ground and the air resistance/friction that is overcome by pedaling to keep a balanced forward motion.

The physics of track cycling

Cycling on an angled surface or on a curved path is slightly more complex as it also requires an inward force towards the center of the curve to maintain the circular motion. This inward force is called the centripetal force.  A centripetal force is a force induced by a cyclist to continue moving at the same speed while taking a turn by tilting their body towards what would be the center point of the corner of the curved lane. In the absence of this force, the cyclist would end up in a straight line and then bump into a tree or a car. In other words, if a cyclist wants to make a turn at a high speed, they must lean more to create adequate centripetal force. Conversely, if they want to slowly turn the corner, they require less centripetal force and turn the corner without leaning much.

Empty Dicklane Velodrome track

Credit: Beena Meena

The centripetal force can also be experienced while taking a leisurely bike ride through the park. The faster you go, the more you have to lean to maintain speed. However, a bike can only bend so much towards the ground before the friction of the ground and gravity takes over and you lose control of the bike.  An inclined surface on the turns can help you with the lean. A velodrome is an example of such space with a closed-looped track and steep banks on each turn. These banks allow cyclists to lean towards the center of the track while maintaining their balance and staying perpendicular to the inclined surface. Given the design of the velodrome, a cyclist riding on its track is subjected to all of the physical forces previously mentioned: forward momentum, friction, gravitational pull, and centripetal pull. However, the shape and banking of the track make the relationship between these forces slightly more complex than your average ride in the park. Therefore, understanding and applying physics is crucial for professional and avid cyclists who enjoy a fast pace but want to stay safe.

How to ride in a velodrome

To successfully ride in the velodrome, a cyclist’s speed must be directly proportional to the angle of the slope and the turn radius of the turn of the track. For DLV, a cyclist can stay on the track with a maximum speed of 55 miles an hour without falling off the track! To put that in perspective, the average speed for a relaxed ride through the park is about 8-10 mph or up to 15 mph on a well-maintained road. The maximum speed for experienced and extremely well-trained cyclists can reach up to 20-22 mph. Velodromes push these limits to the extreme with maximum speeds of nearly 60-70 miles per hour based on a velodrome’s shape and structure.

The velodrome has made track cycling so captivating it has become one of the most popular sports in the Olympics. It’s no wonder that the Atlanta locals who watched the sport in the Munich Olympics were determined to build a velodrome in their own community, which is still popular among Atlanta cyclists nearly half a century later. 

Today, the Dicklane Velodrome is owned by the city of East Point and managed by a volunteer-based, non-profit organization called the East Point Velodrome Association (EPVA). I sat down with Peter Antonovich, the President, and Director of EPVA, to learn more about track cycling and DLV. Peter shares that the velodrome track provides a safe and open space for cycling without concerns of traffic, potholes, or unexpected curves.

Track cycling training

“Track cycling could be intimidating at first but the more you practice, the more you get accustomed to it,” Peter says. Even when a prospective track cyclist understands how the laws of physics apply, they still need extensive training before they can race. The DLV provides certification classes on the weekends during the on-season, which starts in March and ends at the beginning of winter. A track certificate is mandatory to participate in the races. “Newcomers learn how to ride safely on the track through lessons taught by experienced volunteers,” Peter told me. The certification course at DLV costs $60, including the cost of a bike rental. Once you earn the certificate you can join the beginner class to train and race on Tuesday nights. The races are $15 to participate, and free for spectators.

Peter explained that the track bikes are somewhat different than the traditional road bikes. They don’t have brakes and are fixed gear. The only way to control the speed is by pedaling. “You use your legs to slow down and speed up,” Peter says. The idea of not being able to break could be frightening at first, but it is actually safer while you are on the track. You must have a minimum speed in order to keep exerting the centripetal force and moving on the curves, otherwise, gravity pulls you down the slope. “You brake, you fall,” Peter warns.

Chess on wheels

“Track races demand strategic planning and tactics from the cyclists,” Peter says, emphasizing the psychological skill as well as the rider’s ability to pedal fast. The DLV provides a safe and healthy competitive place for cycling enthusiasts to train both their physical and mental fitness. “It’s chess on wheels,” says Peter, smiling.

Whether you would like to put the science of cycling into action with a relaxed ride or with a new hobby of track cycling, understanding a few basic principles of physics will only improve your experience. If you are more inclined to the former, I recommend cycling on the Freedom Park Trail and taking notice of how the winding path will require you to slow down and/or tilt your body at each turn. You can always watch the track cycling races from the safety of the sidelines! If you’re set on trying out track cycling, you can feel fortunate to live so close to a velodrome and get involved with the Dicklane Velodrome. 

Thank you to Peter Antonovich and the East Point Velodrome Association! To learn more about upcoming track cycling events and training, visit

For more Awesome Science of Everyday Life features and other science updates, follow Science ATL on FacebookTwitter, and Instagram!

The Science Behind Urban Scooters

Photo of three electric scooters parked on a curb next to an empty intersection.

By Nkosi Muse

Although we don’t have flying cars and shiny, metallic cities just yet, technology has certainly grown and evolved exponentially in recent years. A large number of these technological advances have been in the realm of transportation: electric cars, buses, and trains. If you live in a major city such as Atlanta, chances are high that you have seen clusters of electric scooters, bicycles, and other gadgets available to help you get around the city. Public response to these vehicles has been mixed, with some people raving about the accessibility and convenience of scooters, while others complain about safety concerns and discarded scooters clogging up sidewalks.

The history of electric scooters

Manufacturer image of a SegwayThe thing is, these scooters aren’t really new pieces of technology, as companies such like Razor and Segway have been selling electric scooters for years. However, they had never been utilized at a major scale until entrepreneurs Matt Ewing, Michael Keating, and Dan Riegel founded Scoot Rides, Inc. in 2011. In 2012, they issued a line of electric mopeds for short-term rental using an app on your phone, followed by electric scooters, or “kicks,” and electric bicycles. The trend picked up, and the rise of the e-scooter industry soared after Bird and Lime introduced their line of scooters in 2017.

In a relatively short amount of time, Bird acquired Scoot Rides and has expanded to almost 100 cities globally, amassing a net worth of approximately 2 billion dollars. Its closest competitor, Lime, racked up over 11 million rides of its electric fleet in 2018, building a net worth of 1.1 billion dollars. Rideshare apps Lyft and Uber also caught on to the trend and added a fleet of scooters to the streets in 2018 to accompany their already extremely profitable driving market. This new method of transport complements the shift towards more environmentally friendly transportation, as many of these companies track their positive impact on the environment and make efforts to be climate-friendly in other areas as well. For example, Lime claims their scooter rides have helped riders avoid more than 1.2 million car trips this year, reducing the amount of carbon emitted into the atmosphere.

Getting down with scooter science

Headshot of Perry Johnson

Perry Johnson, data scientist

While all of these electric scooter companies seem to be masters of business and economics, they are utilizing and largely benefitting from the new and rapidly expanding field of data science. Data sciences are behind almost every advanced piece of technology we access and use, especially if it interacts with the internet. This science has established programming languages as a new universal language, in which we can communicate with computers (big or small), and computers can communicate with each other.

“There is a science behind the placement and operation of these scooters in different cities.”

Programming languages also drive the apps that we use to rent and ride our scooters. I spoke with data scientist Perry Johnson who shared his insight on the data science behind the operation of our beloved (or hated) electric scooters. “There is a science behind the placement and operation of these scooters in different cities,” he says. A city’s population is a heavily weighted factor in whether a scooter company (e.g. Bird) will select it to deploy its fleet of scooters, but the data for the scooters themselves rely on something called an “application programming interface” or “API.” 

What is an API?

Think of an API as a kiosk at the airport: when checking in, the kiosk provides you with a multitude of options such as print bag tags, change your seat, or print your boarding pass. Pressing the button for the kiosk to carry out one of these actions is similar to the function of an API. An API controls what happens between the time you press the button and receive an output. If you ride these scooters, whether or not you realize it, you are using an API.

“These APIs contain scooter data from scooter latitude and longitude coordinates, to battery levels, to scooter IDs,” Perry continued. “When you open your Bird scooter app, your phone is essentially making a call to the API, which in return shows you the location of scooters around you, their battery level, and their ID.” There is also a Nest ID, which corresponds to the “nest” a scooter is placed in—a bird in its nest, if you will! If you happen to see a bunch of scooters in one place, that is most likely a nest, whose location is usually closely related to recorded scooter “hot routes,” city landmarks, and scooter battery level, according to Perry. Any scooter without a Nest ID is most likely a scooter that was taken out of its nest or randomly placed—such as when a rider drives a scooter from a nest to a random, isolated destination.

An innovative approach

The app not only uses data science for its users but for its “workers” as well. Scooter companies such as Bird hire people to charge their scooters and to place them back on the streets for use. To know which scooters to pick up, the app notifies the user which scooters in the area have low battery. When they are fully charged, the app determines where to place the scooters based on nest locations, demand, hot routes, battery, landmarks, etc.

Three Bird scooters parked in a row

Now that you know a little more about these scooters, you may be saying to yourself: “why didn’t I think of this to get rich?” Trust me, so am I. Innovations that deploy an API have become so familiar that they can sometimes seem simple, but there is usually a lot more at work within the machines, computers, and applications we routinely use and view as ordinary. However, the next time you scan a scooter’s bar code to go for a ride (with your helmet on, of course), you’ll have a better understanding of everything the device in your hand just did for you.

How has COVID-19 affected the e-scooter industry?

Like many other public amenities and resources/tools, the presence of the COVID-19 pandemic has sharply reduced the amount of scooters that coat the streets of what was once the Downtown Atlanta scooter hotspott. However, just because quarantine has limited the use of scooter application programming interfaces (APIs), it does not mean that APIs are not being used elsewhere!

In fact, if you use an app like Twitter, Instagram, or Facebook, an API is most likely what is gathering the information from the web server and displaying it on your phone—especially when you look for a specific tweet, profile, or hashtag. Moderating our fun and convenient electric scooter rides are just one of the ways APIs are utilized.

Thank you to Perry Johnson for sharing his data science expertise! To learn more about his work, visit

For more Awesome Science of Everyday Life features and other science updates, follow Science ATL on FacebookTwitter, and Instagram!

How Ink Evolved: The History and Science of Tattoos

Young man with colorful tattoo sleeve.

By Audra Davidson

As most people would be, I was a little nervous. Maybe a bit more than a little. Shiny, sterilized tools loomed just below eye-level, neatly arranged alongside a crowd of sanitizing chemicals. Mind racing and growing increasingly self-conscious about my above-average sweat production, I almost called the whole thing off. The cold shock of disinfectant on my skin finally snapped me into focus; I was really about to do this. I was just glad I couldn’t see the needles.

Biting my lip and clenching my fist to feign toughness and hide my pain, I walked out of that appointment with a swollen lip, nail marks on my palm, and permanent artwork on my ribs.

While it wasn’t the most painful experience I’ve had to date, getting my first tattoo certainly wasn’t the least. According to the Pew Research Center, I was now one of the 40% of Americans aged 18-29 to have a tattoo. Body ink has become so popular in recent years that the US military has had to loosen their strict tattoo restrictions to keep their recruiting pool from shrinking. Why do so many people purposely injure themselves to create these elaborate and permanent scars? Keep reading to learn more about the history and science of tattoos.

An Artistic Rite of Passage

Ouroboros tattoo by Atlanta tattoo artist, Dustin Cramer.

Dustin Cramer puts a spin on the ouroboros, an ancient symbol representing wholeness and the cycle of life. (Instagram: @dustycramer)

“It’s like hanging your favorite art in your home, but of course permanently,” explains Dustin Cramer, a tattoo artist at SparrowHawk Studio in Atlanta. In addition to the deep artistic component, a 2015 Harris Poll showed that inked individuals feel that their tattoo makes them feel sexy and rebellious, as well as strong, spiritual, healthy, and intelligent. This modern rationale for body ink is not too far off from that of more traditional tattoo origins. A practice that has been around for over 4,000 years, tattoos are considered a rite of passage in many cultures, believed to ward off illness and illustrate physical endurance. The ritual of elaborate body inking is deeply spiritual, and studies have indicated a belief that tough bodies and minds create thoughtful warriors and leaders.

Despite the longevity of tattooing, biologists have long been puzzled by this ritual of self-injury. After all, purposefully exposing oneself to injury and risk of infection doesn’t seem like the best way to ensure survival. Yet recent theories suggest that the cultural origins of tattoos may have a biological basis in a phenomenon referred to as “costly honest signaling.”

Costly Honest Signaling

A perfect example of costly honest signaling can be found in one of my favorite movies from the early 2000’s: A Knight’s Tale. In a story about an underdog jousting crew, Heath Ledger’s character, William, must hide his humble origins to win tournaments and the heart of the noble lady Jocelyn. Due to the shady dealings of his arch-nemesis, William becomes severely injured during the final jousting match. Throwing a Hail Mary, he removes all his now ruined armor, charging ahead with no protection. This display is both costly and honest because removing armor is a potentially deadly move that is impossible to fake. While extremely risky, this dangerous act is meant to signal toughness and confidence in the character’s ability to win, shaking the confidence of his dastardly opponent. A successful attempt at costly honest signaling bolsters his romantic prospects and ultimately wins him the tournament.

With the risk of life-threatening infections and a permanent marking that is nearly impossible to fake, biologists believe ancient tattoos are another form of costly honest signaling. Like Williams’s display of bravery to capture victory and Jocelyn’s affections, body ink may have been used as an evolutionary signal to potential partners about the ability to withstand physical pain and fight off infections. By attracting mates, thus increasing chances of reproduction, the pain and risks of this ritual of self-injury may have had cultural and evolutionary benefits that outweighed the costs.

Developing Tattoo Immunity

Dr. Christopher Lynn, Associate Professor in the Department of Anthropology at the University of Alabama, has investigated costly honest signaling theory through the lens of the immune system. Lynn and colleagues compared overall tattoo experience in American Samoans, a culture in which body ink plays an integral role, to markers of immune system response. Immune response was assessed by measuring the amount of two substances in the subjects’ saliva: cortisol and IgA. Cortisol is a hormone released during stress to suppress the immune system and return it to baseline activity, while IgA is an immune marker that serves as the first line of defense for bacterial infections and viruses.

Individuals with more tattoo experience may have immune systems habituated to frequent stressors to the skin, priming them to fight off infections.

Compared to tattoo novices, Lynn’s research shows those with more overall experience with tattoos had elevated levels of IgA in their saliva after getting a new tattoo. Therefore, individuals with more tattoo experience, such as more inking sessions or years having tattoos, may have immune systems habituated to frequent stressors to the skin, priming them to fight off infections.

Photo of a Samoan man receiving a traditional tattoo.

An American Samoan tattoo session. Tattoos are incredibly important to Samoan culture, signifying strength and honor. Traditionally, tattoos are given using the hand-poke method.

Tattoos are thought to have served as a costly honest signal of toughness and health for thousands of years. Although tattoos are likely not the cure to the common cold, Lynn’s work demonstrates that the cultural and evolutionary history of permanent body art may have biological impacts. And while it might not make me a great warrior, that just might help me fight through the pain during my next tattoo.

Thank you to Dustin Cramer and SparrowHawk Studio for their tattoo expertise! To see more of Dustin Cramer’s work, follow him on Instagram at @dustycramer.

For more Awesome Science of Everyday Life features and other science updates, follow Science ATL on FacebookTwitter, and Instagram!



  1. Heimlich, R. Tattoo taboo. Pew Research Center (2010). Available at: (Accessed: 8th December 2019)
  2. Belyh, A. The Army Tattoo Policy: What’s Allowed and What’s Not. Cleverism (2019). Available at: army does not limit,sleeves%2C neck%2C and ears. (Accessed: 8th December 2019)
  3. Shannon-Missal, L. Tattoo takeover: Three in ten Americans have a tattoo, and most don’t stop at one. The Harris Poll (2016). Available at: Harris Poll&targetText=But one thing’s for sure,%25) have two or more. (Accessed: 8th December 2019)
  4. Krutak, L. F. Spiritual Skin: Magical Tattoos and Scarification: Wisdom, Healing, Shamanic Power, Protection. (Edition Reuss, 2012).
  5. Mallon, S. & Galliot, S. Tatau: A History of Samoan Tattooing. (2018).
  6. Bird, R. B., Smith, E. A. & Bird, D. W. The hunting handicap: Costly signaling in human foraging strategies. Behav. Ecol. Sociobiol. 50, 9–19 (2001).
  7. Koziel, S., Kretschmer, W. & Pawlowski, B. Tattoo and piercing as signals of biological quality. Evol. Hum. Behav. 31, 187–192 (2010).
  8. Sapolsky, R. M. Endocrinology of the stress-response. in Behavioral endocrinology (eds. Becker, J. B., Breedlove, S. M., Crews, D. & McCarthy, M. M.) 409–450 (MIT Press, 2002).
  9. Marcotte, H. & Lavoie, M. C. Oral microbial ecology and the role of salivary immunoglobulin A. Microbiol. Mol. Biol. Rev. 62, 71–109 (1998).
  10. Lynn, C. D. et al. The evolutionary adaptation of body art: Tattooing as costly honest signaling of enhanced immune response in American Samoa. Am. J. Hum. Biol. 1–12 (2019). doi:10.1002/ajhb.23347

The Awesome Science of Coffee Production

By Sydney Hubbard

During the summer of 2017, Kayla Bellman was working with Habitat for Humanity delivering latrines, smokeless stoves, and water filters to families living in extreme poverty in a remote region of Guatemala. This particular region, along with many other rural, agrarian areas of Guatemala, had a local economy largely pillared on coffee production. It was during this summer that her team hired a mason, Luis. To make ends meet, Luis worked for Habitat for Humanity and on a nearby coffee farm as a picker. Kayla soon realized that, despite having two jobs, Luis and his family were still living well below the poverty line.

How could such a large, profitable industry, like the coffee industry, leave its laborers and producers so vulnerable?

Workers at a milling and processing station in El Salvador hand-sorting green coffee for defects.

Workers at a milling and processing station in El Salvador

As Kayla continued her work with Habitat that summer, she noticed a pattern: “Most of the families that qualified for Habitat assistance had one or more family members employed as manual labor on local coffee farms. These people had full-time, legitimate employment, and yet they were still living on one dollar a day.” How could such a large, profitable industry, like the coffee industry, leave its laborers and producers so vulnerable? The dots Kayla connected that summer pointed her towards glaring gaps and severe inequities in the coffee value chain and set her on a path not only towards a more mindful consumption of that product but ultimately to a career in development.

It is a little too late in the day for coffee, so I sit with Kayla Bellman and her colleague Aelish Brown over craft beers at the Bookhouse Pub in Atlanta to discuss the fundamentals of coffee production, the coffee value chain and finance sector, and fair trade, among other topics. Kayla is a current student in the Masters in Development Practice program at Emory University and a project intern at Transparent Trade Coffee (TTC), a program at Emory University’s Social Enterprise at Goizueta Center (SEG). Aelish Brown is a program associate at SEG.

As I am a coffee novice in all senses of the word, I ask them to start at the beginning: How does coffee travel from a distant farm in a foreign country into the filter used for my morning drip? Aelish patiently explains this process, known as “bean to cup.”

Where does coffee come from?

Green coffee cherries

Green coffee cherries growing in Guatemala pre-harvest season.

Coffee is grown on trees (genus Coffea) with beautiful white flowers in tropical climates, typically in Latin American, Asian, or African countries. These white flowers produce cherry-like fruits that change color from green to red and are harvested once a year over an approximately three-month period. Inside the skin of these red cherries are several hard seeds, which will become coffee beans. Farms hire local, seasonal labor to handpick the red cherries to procure the seeds inside. If the farm is in an area with access to adequate supplies of water, the seeds undergo a “wet process” in which they are fermented in tanks of water for 24 hours to remove the excess pulp from the fruit and then dried.

Drying patio where honey-processed coffee has been laid out in the sun.

Drying patio at a milling and processing station near Ataco, El Salvador

However, if water is scarce, farms opt for a “dry process” in which seeds are placed on giant patties to dry in the sun, and then the excess fruit is removed. Once the seeds undergo one of these processes, the resulting beans, often referred to as “green coffee,” are sorted by size, graded for quality, and bagged for sale. Individual farms or cooperatives (groups of farms investing in equipment and labor together) then sell these bags to an exporter. Exporters are based out of producing countries. They typically coordinate with importers in consuming countries in the global north (United States, Europe, etc.) to move the green coffee via cargo ships. Importers and exporters coordinate putting this haul in warehouses and listing the types of coffee.

The actual roasting of green coffee takes place in importing countries. The beans are placed in roasting machines and transform into the brown beans we know, love, and purchase in stores.  At this point, a roaster will go to the warehouse, select and buy coffee, and move it to stores and coffee shops where it is ready for consumption. (For a video of the process, here’s NPR’s Bean to Cup.)

The fundamentals of coffee production

The coffee ecosystem includes the labor of farmers and their employees, as well as importers, exporters, roasters, and consumers.  Also swirling around this delicate ecosystem is the finance sector and something called the C price. “Coffee is treated as a commodity by the New York Stock exchange. The trading price of a green pound of coffee is known as the ‘C price,’ and this figure ultimately affects the price of coffee,” Aelish describes. Like other commodities, the law of supply and demand determines the C price. For example, if there is coffee scarcity, the price will go up until consumers stop buying it because it is too high. If there is an abundance of coffee, the price will drop.

The average production cost of coffee ranges anywhere from $1.05 to $1.40 per pound.

Green coffee warehouse in El Salvador, where labelled lots await the final round of milling and sorting before they are ready for export and roasting

Labeled lots await the final round of milling and sorting before they are ready for export and roasting

The C price should reflect how much coffee is available and how much people want it. However, this is not exactly how the C price operates in reality. Much of the pricing around coffee is determined via speculation of what the price of coffee will be on a future delivery date. If there is speculation that the price of coffee will drop in the future (say due to abundance), people will start selling coffee and futures contracts, and the CURRENT price of coffee will drop. Therefore, the C price is not linked to current, real market conditions but to highly variable market predictions, and this can have a severe impact on the price of coffee and coffee producers.

According to Caravela, the average production cost of coffee ranges anywhere from $1.05 to $1.40 per pound. With recent booms in coffee production, the C price has dipped as low as one dollar per pound, leaving coffee farmers in the red. Furthermore, considering that the majority of cost around coffee production is labor, farmworkers like Luis often withstand the worst of this deficit.  And it is in this way that the cycle of poverty remains at the farm level, and profits stay in the hands of large companies.

Third-party certifications of coffee products were born to attempt to fix this problem and to assure consumers the product was harvested under both eco-friendly and economically fair conditions; the most well known of these certifications is “fair trade.” Fair trade guarantees a minimum price for commodities (like coffee) to ensure that laborers in producing countries are paid a just wage. When the C price falls, they are still paid the agreed-upon minimum price for their product. In theory, this minimum price creates a safety net for farmers.

However, if the C price happens to take an upswing, under fair trade rules, coffee growers are paid the same fair-trade price (even if the C price exceeds this price). Or as Aelish put it, “When you create a floor, people will sit on it.” Basically, fair trade ensures that farmers do not lose when coffee prices fall, but they do not gain when the prices climb either. In this scenario, again, the benefits and profits often fall into the hands of large companies. 

Direct-trade coffee alternatives

Many experts in the coffee industry argue that a blanket minimum price is not the solution. Instead, prices need to be based on the real cost of production, which varies by country, and emphasis needs to be placed on transparency along the entire value chain. This is where new buying models and social enterprises like TTC enter the picture.

TTC is one of a number of organizations spearheading a direct-trade approach to the coffee industry. Essentially, direct-trade approaches cut out the middlemen. Small coffee farmers sell directly to buyers and are often paid substantially more in the process. TTC has compiled a list of “Transparently Traded Coffees” that allows consumers to see the effective return to origin, or the percentage of a coffee retail sale that goes back to farm, for each brand of coffee. This information allows consumers to know exactly how much a farmer was paid for his/her product and make their own informed choices about which coffees to buy (Transparent Trade Coffees).

In the end, the ultimate goal of third-party certifications and direct-trade approaches is to get money out of the hands of big corporations and back into the hands of small farm owners and their laborers, allowing people like Luis to provide for their families and lift themselves out of poverty.

Think before you drink

As we finished our beers and our conversation, Aelish Brown made her final call to action: “We all have that one thing we care about: maybe it’s coffee, maybe it’s clothing, maybe it’s this craft beer we’re drinking. Whatever it is, I hope that learning about the value chain of coffee and thinking about where it comes from has incentivized you to care OR at least think more critically about other products. Even if I haven’t reframed the way you think specifically about coffee, even if you don’t practice it day-to-day, I hope you can take this logic and thoughtfulness and apply it to that one thing you care about.”

Thank you to Kayla Bellman and Aelish Brown for teaching us about the incredible science of coffee production! Check out Transparent Trade Coffee for direct-trade coffee that helps support small farmers.

For more Awesome Science of Everyday Life features and other science updates, follow Science ATL on FacebookTwitter, and Instagram!

The Awesome Science of Music Technology


Close-up photo of a hand adjusting dials on a music mixer in the music technology field.

Photo by Drew Patrick Miller on Unsplash

By Amin Ghane

Musicians spend countless hours tweaking, calibrating, and arranging sounds and ideas to create your favorite jams. And then, of course, there are the instruments themselves that provide a conduit through which creativity can be expressed. The field of music technology develops and improves how musicians create – and how we interact with – music.

17th-century music technology

Dating from 1720, this grand piano was invented by Bartolomeo Cristofori.

Breakthroughs in music technology have always led to booms in musical innovation. Consider that most ubiquitous of all Western instruments: the piano. Invented around the 18th century by Bartolomeo Cristofori, the piano was an advancement upon the harpsichord, which introduced the musician’s ability to adjust the volume and duration of the notes played. Classical and Romantic musicians took advantage of these attributes to create some of the most enduring pieces of all time. 

And the work of music technologists hasn’t stopped. In fact, advances in computation have provided musicians the power to produce, edit, and play their music with more flexibility and expression than ever before. Whereas the work of recording and editing music was previously reserved for experts who would charge a fortune for their services, now anyone with an iPad and some curiosity can get into the basics. The latest, top-of-the-line synthesizers are producing noises that grip our attention.

From the underground artist slapping together beats in their garage to the latest number one hit from Taylor Swift, music lovers of all styles benefit from this innovation. To take a look at what’s going on the front lines at the intersection of technology and artistic expression, I ventured to Georgia Tech’s School of Music, which houses one of the country’s foremost academic and research programs in music technology.

The future of music

Innovation on display at Georgia Tech’s annual Guthman Musical Instrument Competition

As I walked into the J. Allen Couch Building, I was immediately greeted by the sound of violins filling the sonic space between gentle scales being played on the cello. These musical instruments are centuries old, but I’m here for what is emerging from the cutting-edge music labs on the second floor. As he leads me upstairs, Avneesh Sarwate, a master’s student in music technology, explains, “Most of those kids also spend a lot of time building synthesizers and coding. Half of them are also in the laptop orchestra.” In a discipline as ancient as music, it is eye-opening to see first hand how intimately the old and new are joined in this hub of experimental music.

In a discipline as ancient as music, it is eye-opening to see first hand how intimately the old and new are joined in this hub of experimental music.

We walk down a long hallway, passing rooms and labs that each have their own character. One room has gigantic speakers surrounding a sole computer monitor, while the next has what looks to be an entirely newly invented instrument made out of scrap metal sitting amid piles of tools and screwdrivers. Avneesh notices my confusion. “Oh yeah, that lab is working with acoustical engineers. I don’t think it’s ready yet.” I intuit that acoustical engineers, who study the control of sound or noise, must play a central role in the development and design of any instrument because they study how different materials and design elements will determine how the sound, well, sounds.

Finally, we arrive at his lab at the end of the hall on the left. As Avneesh swipes his ID card and the door swings open, I’m greeted by what looks, at first, like a traditional computer lab. On second glance, I see some clues about what goes on in here: stacks of keyboards and mixing boards around the room, for example, or the piles of sheet music strewn about on the desks.

“I was a very creative kid growing up. I played guitar and my dad did whatever he could to help me grow creatively,” Avneesh tells me as his computer boots up. “I went to school for software engineering, but I never really stopped playing music. At some point, I just figured I’d use software to help my music and that’s how I got into interactive art.” 

“At some point, I just figured I’d use software to help my music and that’s how I got into interactive art.”

When I ask what he means by interactive art, Avneesh opens a program on his computer and starts typing computer code. Just when I feel I can’t take the anticipation any longer, the speakers on either side of his desk come alive with an ethereal melody looping around a drumbeat that, while simple, demands my attention. “This is a module I wrote that lets you generate melodies with algorithms.” Then, with another line of code, the melody shifts: whereas before the synthesizer was coming out of each speaker equally, the melody now faded between the speakers, almost oscillating, creating a rather gripping effect. I was reminded of the way thoughts swirl together when one is on the cusp of sleep.

Bringing art to life with technology

Live coding in action

What Avneesh is doing is called live coding, creating art in real-time using computer code – whereas software is traditionally written, tested, debugged, and then used, live coding allows one to use programming as an actual instrument, the way you would a keyboard or a guitar. And it doesn’t stop at music.

“Yeah, I’ve actually done this with performance art as well.” He’s referring to Paradise Lost, an “immersive musical theater performance for which I developed interactive graphics.” He shows me videos of performers dancing while he live-coded various graphical effects onto the performance. In one, the dancers are given a wave-like effect while in another, mesmerizing pixelation effect reminds one of a faded memory. Bravely, Avneesh displays the code on the screen the whole time for the audience to see. “That would’ve been a bad time for a typo!” he says with a smile.

Avneesh is especially interested in developing interfaces, ways to foster connection between live-coding musicians and musicians who are playing physical instruments live. In one paper, he prototypes tools that allow traditional performers to see and understand what the coder is doing. One method uses colorful balls to represent notes, which move around in a pattern that corresponds with the code. “A big part of my work is making everything as accessible as possible,” he says. And it’s true – Avneesh has also been part of an effort to create an entirely new platform for creating computer music aimed at non-technologically inclined musicians, thereby opening new doors for creativity.

“A big part of my work is making everything as accessible as possible.”

I peer into another room on our way out, expecting some more engineering and computer equipment. Instead, there sits a lone baby grand piano in the corner facing a few rows of chairs. I smirk, thinking of where we’d be if the harpsichord had never been improved on. Thanks to the work of people like Mr. Cristofori in the 1700s – and Avneesh today – the bounds of music will never stop expanding.

Thank you to the Georgia Tech School of Music and Avneesh Sarwate for sharing their interactive music technology! Follow Science ATL on FacebookTwitter, and Instagram for more Awesome Science of Everyday Life features and other science updates.

The Awesome Science of Traffic

Traffic jam in Atlanta, Georgia.

By Ana Cheng

Atlanta is the 11th most congested city in the country, and most ATLiens are familiar with the frustrating ballet of rush hour traffic. On average, drivers lose 97 hours and $1,348 each year just stuck in traffic. Atlanta is also the fourth fastest-growing city in the country, meaning our roads will have to support increasingly more commuters year over year. However, like with most modern-day problems, there are teams of scientists and engineers heroically searching for ways to improve our lives. I spoke with Dr. Jorge Laval, a civil engineering professor at Georgia Tech who specializes in transportation, to find out more.

What is Traffic Theory?

The field of traffic theory can trace its roots back to the mid-twentieth century, shortly after cars gained popularity. Engineers began measuring traffic flow with cameras and appropriated fluid mechanical concepts to describe the patterns they observed, likening traffic to the flow of water in rivers. Since then, new models and technology have enabled research through advanced simulations of driver behavior. Dr. Laval, who has been studying transportation for twenty years, uses this technology to study traffic patterns. He’s among a handful of transportation researchers at Georgia Tech and part of the Georgia Transportation Institute, a consortium of researchers at various universities working in policy and planning, environmental issues, transportation technology and infrastructure, and traffic operations.

Driving simulator at Georgia Tech.

The Autonomous and Connected Transportation Driving Simulator Laboratory (ACT-DSL), a driving simulator in the lab of Dr. Srinivas Peeta (Georgia Tech) which helps researchers better understand human driving behavior.

Although these researchers use sophisticated simulations and math to understand traffic patterns, one does not need a PhD in civil engineering to understand the real-world effects of congestion. “You’re a driver, so you experience it every day,” says Dr. Laval. Take, for instance, the concept of capacity drop. Capacity refers to the maximum number of vehicles that may pass a given point on a road during a given period of time. Because of varying road conditions like accidents or lane changes, this number might drop, causing a disproportionate effect on traffic. “When [capacity] drops, it goes down by typically 10-20%. It doesn’t sound like much, but in queueing systems like these, that’s a huge difference. It could mean twice the delay,” explains Dr. Laval. 

To understand factors that contribute to changes in capacity on a macroscopic scale, he and other theorists utilize fundamental diagrams, created using data collected by loop detectors (those pairs of black cables laid across the road). Every city or “network” of roads has a unique set of properties that give it a characteristic fundamental diagram, meaning that the diagrams for Atlanta and Los Angeles will be different. Once researchers have obtained a diagram for a specific network, all they need to know to understand current road conditions is the number of vehicles on the road, which they can count with loop detectors. From this, they can glean the average speed and travel time for any given path. For example, researchers can look at the diagram below and find the optimum density of cars for maximum flow or the least traffic (labeled with a red star).

Fundamental diagram of traffic flow

What Causes Traffic?

In order to apply what they know, researchers must first understand what causes traffic in the first place. Freeway on-ramps, accidents, and rubbernecking are obvious culprits. The unifying factor in all traffic jams is human error. Consider the on-ramp scenario: when vehicles enter the freeway, they’re typically going slower than the rest of traffic, creating small disturbances in flow. It’s made worse when other cars start to change lanes, causing disruptions across multiple lanes. In fact, lane-changing activity is the main contributor to capacity drop. In other situations, traffic jams seemingly appear out of nowhere. In these cases, slight variations from driver to driver lead to minute braking and acceleration, which become magnified as following cars react. Dr. Laval calls these stop-and-go waves. 

In downtown areas, traffic is mainly influenced by the length of city blocks and the timing of green lights (called green time). Short blocks mean a lot of stopping and starting, which is a recipe for traffic disaster. If the lights aren’t synchronized efficiently, spillback can happen. Spillback is the phenomenon that occurs when cars move forward because their light turned green, but end up blocking intersections because the next light is still red. The ideal grid has long blocks and short green lights, minimizing the spillback effect. However, if we zoom out on dense urban areas, not even traffic light coordination has much of an effect on the average speed of the network. The main factors remain the block length and average green time.

As for why Atlanta traffic is especially bad; it’s surprisingly not due to our non-grid layout. Dr. Laval blames sprawl and underuse of public transport for increasing the number of vehicles on the road. Moreover, our infrastructure was built using outdated traffic models—and for a much smaller population than that of present-day Atlanta.

Fortunately, Dr. Laval is working on ways to bring our roadways into the twenty-first century. He’s developed a variable speed limit algorithm which adjusts the maximum speed on the freeway to optimize the capacity. “It hasn’t worked really well because people don’t comply,” he laments. It’s because the algorithm can sometimes seem counterintuitive: drivers who read a speed limit of 45 mph tend to drive faster if they don’t see many cars on the freeway, even though the displayed limit will improve the capacity. So now Dr. Laval is hoping to coordinate variable speed limits with real-time ramp metering algorithms—algorithms that respond to current traffic conditions by adjusting the rate of green lights—in a collaboration with the Georgia Department of Transportation (GDOT).

Reducing Traffic Congestion

Diagram of Atlanta's roads, courtesty of Dr. Laval.

Diagram of Atlanta’s roads, courtesy of Dr. Laval.

The unfortunate truth is that to minimize overall traffic, some people would have to take longer routes. It might seem straightforward for every driver to take the most direct route to their destination, but this has a hidden social cost—increased traffic due to congestion on popular roads. Introducing congestion pricing might help accomplish that by making it less enticing to take a busy road if it comes with a pricier toll, even though it may be the shortest route. With this system, “People act as if they’re minimizing their own cost, but they internalize their social cost. That’s one way in theory that you can have people choose their own routes but have tolls such that the equilibrium is going to give you the system optimum,” explains Dr. Laval.

In other words, by making the more socially costly (read: busier) roads more financially costly with tolls, enough drivers will take the cheaper routes that it will minimize the overall traffic. However, it may mean that only wealthier drivers have an improved driving experience. Alternatively, apps like Waze and Google Maps also have the power to offer drivers alternate routes that would improve overall traffic without the economic barrier posed by congestion pricing. Being able to regulate the behavior of every car through an app? “That’s the holy grail of city planning,” says Dr. Laval.

Another simple fix is encouraging more people to utilize public transit options. Studies have found that if 1% of drivers opted for public transit, average commute times could be reduced by 18%. Further, because less congestion would lead to more reliable bus schedules, it would start a virtuous cycle that would make public transit even more appealing and reduce traffic in addition to its environmental and health impacts.

“We know nothing about (autonomous vehicles) and that’s a problem because they’re coming—they’re already here.”

Overall, in order to truly eradicate congestion, we must remove human error from the driving equation. Could autonomous vehicles (AVs) be the grand solution? Dr. Laval explains there’s a shift happening in the field of traffic research as AVs have begun to hit the road. “We know nothing about AVs and that’s a problem because they’re coming—they’re already here,” he says, “We don’t know what they are going to do to capacity. My bet is that it’s going to be bad in the beginning. Due to safety concerns, they will overreact and be very conservative by driving really slowly.” In fact, the current models show that when mixed in with human drivers AVs are worse for traffic, likely due to programming that overcompensates for safety concerns. We may not see the benefits of AVs until they make up the majority of the road. So until their inevitable takeover, take the bus when possible, obey variable speed limits, and don’t change lanes near bottlenecks.

Thank you to Dr. Jorge Laval for navigating through the science of traffic patterns in Atlanta! Follow Science ATL on FacebookTwitter, and Instagram for more Awesome Science of Everyday Life features and other science updates.

Cracking the Science Behind Pottery with MudFire Pottery Studio

By Helen Siaw

MudFire Studio in Decatur, GA

MudFire Studio in Decatur, GA

Two rows of pottery wheels sit at the center of the pristinely clean 8000 square-feet studio, surrounded by shelves of artwork done by the studio’s members, Mudfire Pottery Studio is a go-to pottery studio for the local community. Daphne Ranlett and her partner Deanna Ranlett have been running the studio since 2013. Daphne’s passion for pottery stemmed from a ceramics course in college. “The science behind pottery and the process in crafting it are intriguing.” With a Bachelor of Fine Arts in ceramics from Georgia State University and decades of experience, Daphne is a tried-and-true expert in ceramics.

Clay, water, fire – essential elements in pottery making go back thousands of years. The oldest known ceramic artifact was a figurine constructed about 32,000 years ago in the early Stone Age. In the Bronze Age, the invention of glazes and pottery wheels opened a realm of new possibilities for artists to shape and decorate. Today, local studios like MudFire Pottery Studio provide the community a place to create and innovate these ancient elements.

It All Begins With Clay

Clay contains a mixture of minerals, which determine the temperature needed to transform soft clay into hard ceramics (firing temperature). Kaolinite is one of the major clay minerals. In kaolinite, two minerals are linked together by oxygen atoms to form a sheet-like structure. Similar to how buttercream frosting holds a two-tiered cake upright, molecular interactions between the mineral sheets help to maintain the shape of the clay. When force is applied to the clay these interactions allow the mineral sheets in the clay to slide past each other. This unique property allows it to be shaped and formed by the potter.1

Meredith Bradley, one of the studio’s resident artists, showed us how to shape wet clay on a pottery wheel.

Meredith Bradley, one of the studio’s resident artists, showed us how to shape wet clay on a pottery wheel.


The wet clay can be shaped using a hand building method or with wheel throwing. With hand building, potters frequently use simple tools to create a piece. Wheel throwing utilizes a pottery wheel. This method depends on a balance between the force exerted on the clay when the pottery wheel spins and the friction between the clay and a potter’s hand. “Wheel throwing is all about the rhythm,” Deanna says with a smile. 

Once a piece is molded into the desired shape, the pottery is left to dry before firing. “You have to let water evaporate from the clay as much as possible before firing. Otherwise, any water trapped in the clay body will turn into steam at 100oC, and it will burst the clay piece,” Daphne warns. 

The air-dried pot is then heated to drive off any lingering water. This heating process transforms the sliding mineral sheets into a stronger network of crosslinked clay particles. From this stage, the clay cannot be reshaped by adding water. Now, layers of ceramic glaze can be applied to this piece, for either decorative or practical purposes such as holding foods.2 

Artists’ Experiment

MudFire studio has a kiln room for members to fire their artworks. They also have an impressive collection of glazes.

MudFire studio offers an impressive collection of glazes.

Ceramic glaze consists of metal oxides, which give colors to glazes because of their light-absorbing properties.2 As a result of this light absorption property, we see the complementary color. For example, when orange light is absorbed by a metal oxide, we see the blue color. “Cobalt gives a blue color, iron gives a brown color, manganese gives a pink color,” Daphne explains as she shows us the mini ‘laboratory’ they have for preparing glazes.

“We like to experiment and mix our own glazes. We melt each glaze ingredient at a different temperature and observe what will happen. Then we mix different ingredients at different concentrations to see if we can get a different effect.” Through this trial-and-error process, artists at Mudfire Studio created 22 new glazes from scratch.

Bracing the Heat!

Pottery produced by resident artists are available for sale at the studio.

Pottery produced by resident artists are available for sale at the studio.

At the back of the studio is where all the firing happens – in a furnace called a kiln. MudFire carries three different types of kilns: electric, soda, and raku. “An electric kiln is basically an oven with a built-in temperature sensor. There’s not much interaction,” Daphne says. Firing with an electric kiln is similar to baking cookies in an oven. The potter has no control over firing conditions besides the temperature and firing time.

With soda firing, a drop of soda ash solution is added to the large gas furnace at peak temperature it vaporizes immediately and attracts the soda ash to particles in the clay and to the glaze, giving unique patterns. “It’s magical! You have no ability to control where the soda deposits or the final firing pattern. It’s submitting to the will of the firing elements,” says Daphne.

Raku firing, the last method offered at the studio, operates very differently from other firing techniques. The clay piece is first quickly heated up to 1800 oC in the furnace, then immediately placed in a bin with combustible materials such as newspapers, causing simple chemistry to take place. The newspaper reacts with oxygen in the air and generates carbon. The carbon then reacts with the oxygen in glaze’s metal oxides and strips it away, a process known as reduction.3 Raku firing tends to produce thin and fragile pottery with easily chipped glaze surface due to its rapid-firing process.4 “Raku is not food and beverage safe. It’s just decorative,” Daphne says as she walks us through the warm kiln room. 

Where Clay Meets Community

MudFire studio resident artists, Kaitlyn Chipps, Meredith Bradley, Marisa Mahathey, and owner Daphne Ranlett (middle).

MudFire studio resident artists, Kaitlyn Chipps, Meredith Bradley, Marisa Mahathey, and owner Daphne Ranlett (middle).

Whether you are a pottery expert or a beginner, Mudfire Studio opens their door to everyone. “We aim to create a safe space for expression,” she explains, “Leave your baggage at the door. Come on in and create.” Besides ceramics, Daphne and Deanna value mentorship to young ceramic artists. They work closely with other young pottery business owners and are in the process of setting up professional development workshops. For more information about Mudfire Studio, you can find them on Facebook, Instagram, and Twitter, or visit

“What’s the next step for MudFire after this?” I ask.

“Global domination,” says Daphne.

Thank you so much to Daphne Ranlett and the artists at Mudfire Pottery Studio for taking us through the science of behind pottery! Follow Science ATL on FacebookTwitter, and Instagram for more Awesome Science of Everyday Life features and other science updates.

1 Breuer, S. The Chemistry of Pottery. Education in Chemistry, July 2012, pp 17-20.
2 Bloomfield, L. Techno File: The Chemistry of Color. Ceramics Arts Network Daily,
3 Whitaker, G. Using the Raku Glazing Process to Show Oxidation-Reducation in Chemistry. U.S. Department of Energy, Pacific Northwest Laboratory, pp 6.51-6.59.
4 Branfmann, S. Successful Tips and Techniques for Raku Firing. Ceramics Arts Network Daily,

The Awesome Science of Apples at Mercier Orchards

By Laura Mast

Apple orchard at Mercier Orchards.

“There’s a lot more science than people realize. People think, you go out there, you dig a hole, you plant a tree and pick it. There’s a lot more.” David Lillard, orchard manager at Mercier Orchards, leans back in his chair and smiles good-naturedly at me and Ian Flom, Mercier’s brewmaster. Flom adds, “I grew up local, in this area. I knew Mercier’s was an apple farm, but I didn’t realize how extensive the process was until I actually became an employee here.”

“There’s a lot more science than people realize. People think, you go out there, you dig a hole, you plant a tree and pick it.”

In its 75 years of operation, Mercier Orchards has grown to over 300 acres with over 100 thousand fruit trees. Nestled in the North Georgia Mountains, it’s blessed by temperate conditions perfect for growing apples: moderate summers, cold winters, and high humidity. Lillard tells me they get 60” of rain every year. 

These features, though, also present dangers. Moisture is also great for pests, and an early frost in the spring could kill the budding fruit. Keeping these many trees – and the new trees they buy each season- healthy and hearty, takes a careful eye, hard work, and of course: science. 

A flood of pheromones, and a blanket made of ice

Lillard has a few tricks up his sleeve to handle pests and frost. 

“There’s just no way I can fight that disease cycle organically in this neck of the woods,” says Lillard. But instead of using pesticides every year, they rotate in four-year cycles. They’ll do a round of regular pesticides in one year, and then for the other three, they do an organic treatment focusing on the two most prevalent pests: the oriental fruit moth and the coddling moth. 

Each spring, orchard laborers go into the fields and hang lures from the branches of every other tree. These lures, which look like bread ties, are soaked in insect pheromones, and flood the orchard with scent for the next 90 days. These confuse the male insects, who use the smell to track female insects. As a result, the males are unable to locate and breed with female insects. 

If insects are a long-term issue, weather is a short term one. “I spent a lot of time, effort and money getting a crop to a certain point and I could lose everything in five seconds if Mother Nature decides to take from us. You have to be pretty zen to work in this industry,” says Lillard.

“You have to be pretty zen to work in this industry.”

If the temperatures are forecasted to drop so much that the apple buds are in danger, Lillard turns on an overhead irrigation system. This system mists water vapor over all the trees. As the water condenses on the trees, it goes from a gas to a liquid. This is an exothermic reaction, meaning the water releases heat onto the buds, keeping them warm. 

Keeping trees healthy is important because if “a tree gets sick,” says Lillard, “that’s it. There’s no cure- only prevention.” 

One particular strategy for keeping trees healthy is, unsurprisingly, starting out with healthy trees.

Where do baby trees come from?

Close up on gardener man hand grafting apple tree

Well, in the case of apple trees, it’s not quite what you think. Apple trees are not “true to seed:” that is, if you were to take the seeds from your Red Delicious apple at lunch and plant them, and grow them into a tree, the fruit from that tree would not produce Red Delicious apples. “They might taste like cork, but it will be an apple,” laughs Lillard. 

Ninety-nine percent of all apple trees in the US are produced using a technique called grafting. A grafted apple tree consists of two parts: the rootstock, which includes the roots and the base of what will be the trunk of the tree, and the scion, which is the stem. A wedge is cut out of the rootstock, and the base of the scion is cut into a wedge. The two ends are jig-sawed together and wrapped until they heal together. You can see this junction in a young tree as a distinct bulge in the trunk a few inches above the ground.

While it’s easy to see the role of the scion- it creates the apple varietal you want! – the role of the rootstock is a little more complex. The rootstock controls the size of the tree, the age when the scion will start to produce fruit, how the tree responds to adverse conditions like weather, insects, and diseases, and more. 

Most orchards, including Mercier, order their trees from nurseries. It takes three to four years to grow the rootstock, and then several more years before the tree is ready to bear fruit. 

Predicting the future

Close up shot of a bag of apples from Mercier Orchards.

Image credit: Select Georgia

“I’m 5, 6, 7 years down the road before a tree is going to produce so I got to make sure I get what you want in seven years,” says Lillard. To choose new apple varieties, he and his team will go to horticulture shows and taste test: “We sit down and we’ll sample 100 apples, and we’ll figure out what they taste like. We learn how it’s been growing in the nursery, some other characteristics and then we’ll say hey, that’s a good one. We’ll plant that one and we’ll try that one.”

“I’m 5, 6, 7 years down the road before a tree is going to produce so I got to make sure I get what you want in seven years.”

After working in the orchard for twenty years, Lillard knows his trees: where you could get out fancy scientific gadgets to measure color and sugar, he just uses his hard-earned experience.

“There’s not a lot to it,” says Lillard. “If I know it’s that time of year, so if I know that reds come in at the beginning of September, I’m looking at Red. Do they have enough color? Are the seeds black? Do they taste good?”

You can always try taste-testing yourself: Mercier Orchards offers U-Pick weekends through the summer through the fall, during prime harvest seasons, complete with tractor rides throughout the farm. Put it in your calendar! “If I like them, and they’re ready to go, well, that means you’re gonna like them.”

Can one bad apple really spoil the bunch?

Assortment of apples from Mercier's Orchard

Assortment of apples from Mercier Orchards

Turns out, yes, and here’s where the cool science comes in with harvesting: storing the apples. You may have noticed that just about any time of year, you can buy apples, as if they were just freshly picked yesterday. This is the result of treatment with 1-methylcyclopropene, or 1-MCP.

As fruits ripen, they release a natural plant hormone called ethylene. This gas prompts the plant to ripen even further: the fruit becomes softer and sweeter, until your forgotten apples are mealy and soft. The ethylene binds to ethylene-specific receptors in the apple skin, which fit together just like a jigsaw puzzle. 

1-MCP looks very similar to ethylene, and it can trick the receptors into letting it bind in ethylene’s spot. 1-MCP treatment fills all the receptors for ethylene with 1-MCP instead, effectively hitting pause on ripening. 

This allows growers to ship out fresh fruit all year round, so you can make your own apple pie any time of year (or, pick up your own or order from their store any time!). 

Come for the apples, stay for the (hard) cider

Display of apple ciders and beverages at Mercier Orchards.

The Tasting Room at Mercier Orchards

At Mercier Orchards, the  apples are divided: of course, there’s fruit for sale in the marketplace, and a good portion goes to the kitchen for pies, fried pies (you haven’t lived until you’ve had one, they sell over one million annually), breads, jams, preserves, relishes, butters and all kinds of sauces, and more. But the rest goes to cider, both hard and regular. This is Ian Flom’s territory. As the brewmaster, he’s led the production of hard cider in particular; regular cider has been an orchard staple for decades.

“When I started making cider, it was just a way to get rid of fruit that I couldn’t sell in the market. Now, I set aside blocks of trees purposely as cider fruit,” says Lillard. This has allowed Flom and his team to experiment with a lot of different flavors. Flom says the most variability in regular and hard cider flavors come from the apples: with 10,000 varieties of apples, it’s easy to see how. 

The main things to consider are sugar content and acidity, says Flom. “You’re not going to have the same acidity level in a Red Delicious versus a Mutzu or a Granny Smith, right? Well, just that difference in the acidity can change your flavor profile of your juice. If you were to heavy on the reds and get, let’s say, one part green apple, and then you’re not gonna have the same tartness after fermentation.”

Fermentation is done very similarly to wine: yeast is added to the apple juice mixture, and it consumes sugars, producing alcohol. Fermentation only takes about two weeks; in fact, for a 500 gallon batch of hard cider, going from apples to bottle takes only 18 days. But it’s after fermentation that the fun begins.

Experimenting with Flavor

Flom tends to experiment with small batches (3.5 gallons) at home before bringing his ideas to work. He says the open-minded and passionate attitude of the team has led to some fun discoveries. 

The Just Peachy recipe, a hard sweet peach cider, transformed along this vein. “I remember, David asked me ‘why don’t we do something hot?’ Why not? And then you know, through some trial and error, we end up with the Jalapeacho, which is one of our top sellers.” 

Another example is the Gone With The Ginger, a sweet hard cider that was born after Flom had been cooking at home. “What if I put some ginger in it? What if I cut it up first, what if I roast it, cook it? So it’s a little trial and error.”

Regular cider doesn’t require nearly as many steps. After the apples are juiced, the juice has to be pasteurized. At Mercier Orchards, they use two different pasteurization methods. The first process, full pasteurization, heats the juice to 180 degrees, yielding a cider that’s shelf-stable for up to two years. Flash pasteurization, however, only heats the juice very quickly to 161 degrees for a matter of seconds. The flash pasteurized juice retains more flavor but doesn’t last as long.

Modern agricultural science at Mercier Orchards

Exterior shot of Mercier Orchard's store.

Image credit: Select Georgia

Tim Mercier, CEO of Mercier Orchards, has said he believes the company’s willingness to learn, adapt and change are their most important assets, something that Lillard and Flom strongly support.

Years ago, the farm was only open from September to December; now, 12 months a year you can head to the farm and do so much more than buy apples. Beyond the bakery, the café, the winery, and the marketplace, you can also take a cooking class, do a tasting, take a tractor tour with a guide, or get out in the fields and pick fruit yourself. Every year brings new varieties of apples, and they’ve expanded to peaches, blueberries, blackberries, strawberries, and nectarines as well.

So load up your family, and take them up to Mercier Orchards for a day outside, with a cup of hot cider, a fried pie, and see this family farm do modern agricultural science for yourself.

Thank you so much to David Lillard, Ian Flom, and everyone at Mercier Orchards for taking us through the science of apple growing! To keep up with Mercier Orchards, follow them on Facebook and Instagram. Check out their website for the most up to date information (and to place any orders!):

Follow Science ATL on FacebookTwitter, and Instagram for more Awesome Science of Everyday Life features and other science updates!

Atlanta’s Living History: Old-Growth Forests in the City

By Elizabeth Spiers

“Grandmother” Beech, Cascade Springs Nature Preserve, photo © Kathryn Kolb

When I greet Kathryn Kolb near Proctor Creek Trail, she leads me towards a slope, “This little patch right here, is attached to a large tract of old-growth forest. It looks like nothing, but it does have some characteristics that are consistent with areas where we find old forests. There’s a steep slope and narrow stream corridor, so people didn’t disturb the soils here when they started farming and building”. We’ve met to discuss the history and ecological impact of old-growth forests and trees in the Atlanta region.

Kolb has worked with organizations such as The Wilderness Society, Georgia Forestwatch, Georgia Conservancy, and Trees Atlanta to raise awareness and provide education on the important processes and roles that trees can provide. Kolb has been a naturalist for over 30 years in the Southeast United States and is an expert on old-growth forests within the city of Atlanta. 

What Are Old-Growth Forests?

Old growth trees near Atlanta, GA

Old-growth forests still exist in small pockets throughout Atlanta.

Old-growth forests are typically defined as an area of land undisturbed by human agriculture or development for 120 years or more. The soil and plant life in these areas has remained relatively untouched from human influences. 200 years ago, Atlanta was home to an expansive old-growth forest. These forests provide unique ecological features, including large trees, multi-layered canopies, rich soils, and unique biological niches for native species. [Image 1] Kolb explains, “A lot of the trees in old-growth areas are not necessarily older trees, they’re younger trees. It’s possible to tell an area is older from native plants, called indicator species, such as bloodroots, trilliums, and hepatica”. Most of these species have seeds that are not distributed by wind or transported by sticking to larger animals. The seeds are distributed by ants or just fall close to the mother plant, so they are a continuation of original plants and don’t migrate from other areas. An abundance of these ‘indicator species’ signifies the soil and root networks have been mostly undisturbed by development or agriculture.

As Kolb leads me into an area of old-growth forest, the vibrant natural diversity becomes almost immediately apparent. Invasive ivies abundant along the road completely disappear. Within fifteen minutes we encounter beech, pine, sourwood, hickory, oak, black gum, and tulip trees. Kolb has an expert eye, identifying the various species and pointing out each to me as we walk. 

Atlanta’s Biodiverse History

Kolb emphasizes how the history of Atlanta is unique from most other major metro cities in the United States. The primary difference being that Atlanta’s development was relatively late, beginning around 1821, almost 100 years after most other major cities on the eastern seaboard. Shortly after, the Civil War began, and the area stayed in a depressed and rural condition. Wide development and expansion of Atlanta didn’t truly begin until the 1960’s, Kolb explains. The byproduct of this slower development is that Atlanta didn’t go through the sprawling intermediate phase most other cities went through, resulting in the retention of ‘old-growth forest’ throughout metro Atlanta. This is a unique characteristic of a major city in the United States. Few other cities harbor ancient trees and soils that provide such rich biodiversity. The untouched soils and tree growths around Atlanta are not only unique, they also provide important natural resources and biological processes that benefit our city.

In addition to providing a link to the history of the land, Kolb explains that these trees all provide practical resources to our community. One is controlling storm run-off. When tree root networks are removed from an area, the soils are easily washed away by stormwater. However, when the tree root networks are maintained, the roots hold the soil in place, preventing erosion and loss of hill slopes. The rich soils in these older, undisturbed areas also absorb water, preventing the water from flooding down-slope regions. Increases in urban development and concrete abundance, prevent water from being absorbed into the ground, leading to larger amounts of flooding. This is easily seen around the city when giant puddles form on the sides of roads and sidewalks during storms. Areas that have large tree populations are less prone to such issues.

It’s All About the Soil

Image of a forest floor, covered in pinecones, straw, and twigs.

The soils in remnant forests not only absorb storm runoff but contain unique fungi. Those fungi have partnerships with all the other species. “It’s all about the soil”, explains Kolb. During our walk, I notice that the soil does, in fact, feel different underfoot. It is very soft with a thick layer of debris and organic material on top, causing my shoe to sink nearly an inch into the ground as I walk. Microbe and fungi populations within this thick layer of organic material and soil work together in a biodiverse network, promoting the growth and life cycle of native species.

Think of a biodiverse forest network like a city. The roads, people, houses, and stores all work together to provide a thriving community. In a similar way, the trees, fungi, microbes, soil, water, and plants all work together through chemical, biological, and geological processes to help one another thrive and grow. For example, orchids are fully dependent on fungi for their seed germination and life cycle. Without fungi, they cannot reproduce new flowers. And orchids are not alone; many native forest species depend on the interconnected system of tree roots, rotting organic matter, fungi, and microbial populations in the soils that these untouched forests contain. 

Take a Deep Breath

Another benefit to native tree populations and old-growth forests is they clean our air of pollutants through photosynthesis, the process by which plants metabolize energy and grow. Plants convert light energy from the sun into chemical energy that the plants can use as food. In this process, the plants take in carbon dioxide (CO2), water (H2O), and sunlight and then convert those into carbohydrates (CH2O), which the plants use to grow, and oxygen (O2), which goes into our atmosphere. When the plants and trees take in carbon dioxide and release oxygen, they help improve the air quality in our neighborhoods. In 1994, trees in urban forests in Atlanta removed an estimated 1,196 metric tons of air pollution at an estimated value to society of $6.5 million. Larger, older trees such as those in old-growths are especially good at this process and can process a much larger volume of carbon dioxide than younger trees can within a year.

A Living History

Kolb works through organizations and community networks to protect and raise awareness of the utility of forests, but also the aesthetic and emotional value they provide. Through her work and the work of other area naturalists, Atlanta has earned a reputation of being a highly forested city with rich tree canopies. These trees are not only practical resources, they are also a living history of the city of Atlanta. As we walked further into the pocket of forest, we approached a large beech tree, much larger than any of the other ones we had encountered. [Image 2] Kolb estimates based on its size, it may be older than 200 years. To try to get an idea of the tree’s age, we examined the etchings on the tree made by other people decades ago, “Keith + Franklin, 1977”, “1956, Roy F”, “W, 1911.”

Photo collage of etchings on an old beech tree.

Etchings on an old beech tree, showing a living history of Atlanta.

Some of the markings are old enough that they have been stretched to the point of unreadability as the tree has grown. It is a tall, gorgeous sentinel, that has withstood Atlanta’s continuous growth, a larger than life illustration of how these forest remnants are a natural part of our city’s past, present, and (hopefully) future. 

Thank you so much to Kathryn Kolb for taking us through a journey of Atlanta’s biodiverse history! Learn more about Atlanta’s public old-growth forests here, visit Kathryn’s website, and get involved with EcoAddendum, which raises awareness of Georgia’s natural environment. Follow Science ATL on FacebookTwitter, and Instagram for more Awesome Science of Everyday Life features and other science updates!

The Science Behind Honey with Urban Honey Bee Project

By: Brielle James
Photos provided by Jennifer Leavey

On the roof of the Georgia Institute of Technology’s Clough Undergraduate Learning Commons sit four waist-high stacks of white boxes. For about 200,000 Western honey bees (Apis mellifera), these boxes are considered home. Together, the boxes (known as supers or hive boxes, each containing numerous wooden frames for the bees to build their honeycomb on) form four beehives belonging to the Georgia Tech Urban Honey Bee Project.

Since the Spring of 2013, the Urban Honey Bee Project, led by Dr. Jennifer Leavey, has maintained anywhere between two and seven hives on the roof of this building. “Once I brought bees to campus,” Dr. Leavey said, “people were really interested in using them for research and learning how to keep bees.” Western honey bees, which originated in eastern Europe, are the most widely managed bees in the world, supplying honey for a worldwide commercial market. How they do this is driven mainly by their biology, allowing them to work together as pint-sized chemists to create the honey we all love.


Survival of the colony and honey production requires a group effort from all of the bees in the hive. In every honey bee hive, Dr. Leavey explained, there are 3 types of bees: the queen, worker bees, and drones. Queen bees are responsible for laying and fertilizing eggs (known as brood) to grow the colony.

Pointing out the queen bee in the hive

Pointing out the queen bee in the hive

Worker bees, which are all nonreproducing female bees, make up the majority of the colony. “Worker bees do different jobs at different ages,” Dr. Leavey says. Young bees work inside of the hive as “nurse” bees to eggs and larvae, queen attendants, and hive janitors. As the bees age, they transition to guard bees at the hive entrance and then foragers. 

Lastly, there are the drones, which are male bees whose only job is to mate with queens from other colonies. Compared to worker bees, there are not many drone bees in the colony. “Depending on the time of year there are none of them [drone bees] in the hive. They kick them out in the fall. They don’t feed them, because they’ll raise more in the spring,” Dr. Leavey says. 


The first step in honey production relies on the forager bees collecting nectar from plants. Honey bees collect the nectar in their honey stomachs, which contain a digestive enzyme called invertase. This enzyme breaks down the nectar’s sugar molecules (splitting sucrose into fructose and glucose). Upon returning to the hive, the forager bees then regurgitate the nectar into cells of the honeycomb. The nectar is repeatedly ingested and regurgitated by the hive bees, adding additional invertase to continue breaking it down.

“[Invertase] is the same enzyme that’s used in the sugar industry to take the fructose produced by corn and produce high fructose corn syrup,” Dr. Leavey says. “So chemically it’s almost impossible to distinguish high fructose corn syrup from honey.” The only way to tell that honey is, in fact, honey is by the residual pollen in it, but big honey producers ultra-filter their honey to sell honey that appears clear and perfect. As a result, “they’ve removed the only thing that distinguishes honey from sugar syrup.”

Chemically, it’s almost impossible to distinguish high fructose corn syrup from honey.

How much honey a hive produces depends on the colony and can vary yearly, but Dr. Leavey says this usually ranges from 50 to 100 lbs of honey per year. She usually takes less than 50 lbs of excess honey from her hives in the mid-summer after the main nectar flow. To do this, she must first harvest the honey. “Sometimes we just take frame by frame,” Dr. Leavey explained. “We’ve got a soft brush and we’ll just brush any bees off and then put [the frame] in a box with a lid.” As she described this initial step, she also shared one of her tricks to harvesting – “if you do it at a time when stuff is still blooming, the bees don’t get mad,” she said. Next, the honey must be extracted out of the honeycomb. Dr. Leavey explained that “if you remove [the honey] from the comb, you can put the comb back for the bees and then they don’t have to make more wax.” A nice way to reduce, reuse, and recycle! 

To extract the honey, students at the Urban Honey Bee Project use a knife to cut the wax off of the comb that the bees have used to seal the honey. The comb then goes into an extractor, a centrifuge that spins the honey out of the comb using centrifugal force. The honey slowly drips to the bottom of the extractor, which has a spout through which the honey can be collected. Beekeepers then strain the honey through screens to filter out any pieces of remaining wax. Wax and pollen can be starting points for crystal formation (solid sugar granules) in the honey, making it gritty and less desirable to eat. Crystallized honey also comes with risks. “If your regular honey, that’s well dissolved, is 83% sugar and then now you’ve got crystals forming, the resulting fluid will have higher water content. If you have higher water content, you can get fermentation to start to occur,” explained Dr. Leavey.


Within the honey bees’ hive, there are different storage areas – honey stores, pollen stores, and brood. “The brood area [in the hive] is basically, in 3D space, the size of a football…and then above the football would be where all the honey is stored and then kind of to the sides and underneath is where the pollen tends to be stored,” Dr. Leavey explained. The brood area is home to all of the baby bees as they grow, while the honey and pollen stores provide the colony with food. “When you open up a beehive, in general, you’ll see all the bees in the brood area, because the nurse bees are really busy there,” Dr. Leavey says. It is there where the queen lays her eggs, which hatch into larvae. Once hatched, nurse bees feed the larvae royal jelly. Royal jelly is “the breast milk of bees,” according to Dr. Leavey, a substance full of vitamins and growth factors produced by bees from glands in their neck. Larvae eventually transition to a diet of pollen and honey before they are capped in the honeycomb to undergo metamorphosis into an adult bee.

Interestingly, queen bees are fed royal jelly their whole lives. “The only difference between a queen bee and a worker bee is what they’re fed. Once the workers start getting fed pollen it changes gene expression and it changes their development,” Dr. Leavey explained. This difference in diet leads to distinct behavioral characteristics. For example, the bigger, fertile, longer-lived queen bees leave the hive to mate, unlike the smaller, sterile worker bees.

In the hive are also the bees’ pollen stores, known as “bee bread.” Bee bread is fermented flower pollen and is the primary source of protein for the hive. Forager bees collect the pollen from flowers and groom it off of their body into “pollen baskets” on their hind legs. “They do add a little bit of nectar to the pollen to make it this dough-ball of pollen that they carry,” Dr. Leavey explained. This pollen load is then carried back to the hive and packed into comb cells for storage. The bees add nectar, honey, and saliva to the pollen when they pack it. “You can kind of smell it when you open a hive. It has that yeasty smell. There are microbes that mix with the pollen and ferment it a little bit and that’s what they use to feed the larvae,” Dr. Leavey says.


While the complexities of a honey bee colony allow it to thrive, these complexities also make it easy to disrupt. “It’s very hard to keep bees now,” Dr. Leavey says. “There are three contributors to colony collapse. It’s pesticide exposure, disease, and poor nutrition.” The latter results from a lack of habitat and appropriate floral resources for the bees.

Help support bees by planting bee-friendly flowers and trees

To help support the bee population, Dr. Leavey suggests planting flowers that are easy to look at, like sunflowers, which a lot of bee species visit. She also recommends reading lists of region-specific pollinator-friendly plant species published by the Xerces Society and planting trees, specifically tulip poplar trees in Atlanta. “I think trees are great just because one tree has so many flowers,” she says.

The Urban Honey Bee Project is committed to supporting these pollinators and the environments that they need to thrive through a wide range of research and outreach efforts to help local community partners establish their own beehives. To keep up with the Urban Honey Bee Project, checking in on the bees via the “bee-cam” or getting involved as a volunteer, visit their website. You can also follow them on Facebook for more updates.

Thank you to Jennifer Leavey and everyone at Georgia Tech Urban Honey Bee Project for teaching us about the awesome science of honey production. Follow Science ATL on FacebookTwitter, and Instagram for more Awesome Science of Everyday Life features and other science updates!