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Sunflowers make small moves to maximize their Sun exposure – physicists can model them to predict how they grow
Charles Darwin’s detailed observations of plant movements, such as sunflower circumnutation and self-organization, reveal how randomness helps plants optimize growth and adapt to their environments. Sunflowers!
Last Updated on March 6, 2026 by Daily News Staff
Chantal Nguyen, University of Colorado Boulder
Sunflowers make small moves to maximize their Sun exposure – physicists can model them to predict how they grow
Most of us aren’t spending our days watching our houseplants grow. We see their signs of life only occasionally – a new leaf unfurled, a stem leaning toward the window.
But in the summer of 1863, Charles Darwin lay ill in bed, with nothing to do but watch his plants so closely that he could detect their small movements to and fro. The tendrils from his cucumber plants swept in circles until they encountered a stick, which they proceeded to twine around.
“I am getting very much amused by my tendrils,” he wrote.
This amusement blossomed into a decadeslong fascination with the little-noticed world of plant movements. He compiled his detailed observations and experiments in a 1880 book called “The Power of Movement in Plants.”
In one study, he traced the motion of a carnation leaf every few hours over the course of three days, revealing an irregular looping, jagged path. The swoops of cucumber tendrils and the zags of carnation leaves are examples of inherent, ubiquitous plant movements called circumnutations – from the Latin circum, meaning circle, and nutare, meaning to nod.
Circumnutations vary in size, regularity and timescale across plant species. But their exact function remains unclear.
I’m a physicist interested in understanding collective behavior in living systems. Like Darwin, I’m captivated by circumnutations, since they may underlie more complex phenomena in groups of plants.
Sunflower patterns
A 2017 study revealed a fascinating observation that got my colleagues and me wondering about the role circumnutations could play in plant growth patterns. In this study, researchers found that sunflowers grown in a dense row naturally formed a near-perfect zigzag pattern, with each plant leaning away from the row in alternating directions.
This pattern allowed the plants to avoid shade from their neighbors and maximize their exposure to sunlight. These sunflowers flourished.
Researchers then planted some plants at the same density but constrained them so that they could grow only upright without leaning. These constrained plants produced less oil than the plants that could lean and get the maximum amount of sun.
While farmers can’t grow their sunflowers quite this close together due to the potential for disease spread, in the future they may be able to use these patterns to come up with new planting strategies.
Self-organization and randomness
This spontaneous pattern formation is a neat example of self-organization in nature. Self-organization refers to when initially disordered systems, such as a jungle of plants or a swarm of bees, achieve order without anything controlling them. Order emerges from the interactions between individual members of the system and their interactions with the environment.
Somewhat counterintuitively, noise – also called randomness – facilitates self-organization. Consider a colony of ants.
Ants secrete pheromones behind them as they crawl toward a food source. Other ants find this food source by following the pheromone trails, and they further reinforce the trail they took by secreting their own pheromones in turn. Over time, the ants converge on the best path to the food, and a single trail prevails.
But if a shorter path were to become possible, the ants would not necessarily find this path just by following the existing trail.
If a few ants were to randomly deviate from the trail, though, they might stumble onto the shorter path and create a new trail. So this randomness injects a spontaneous change into the ants’ system that allows them to explore alternative scenarios.
Eventually, more ants would follow the new trail, and soon the shorter path would prevail. This randomness helps the ants adapt to changes in the environment, as a few ants spontaneously seek out more direct ways to their food source.
In biology, self-organized systems can be found at a range of scales, from the patterns of proteins inside cells to the socially complex colonies of honeybees that collectively build nests and forage for nectar.
Randomness in sunflower self-organization
So, could random, irregular circumnutations underpin the sunflowers’ self-organization?
My colleagues and I set out to explore this question by following the growth of young sunflowers we planted in the lab. Using cameras that imaged the plants every five minutes, we tracked the movement of the plants to see their circumnutatory paths.
We saw some loops and spirals, and lots of jagged movements. These ultimately appeared largely random, much like Darwin’s carnation. But when we placed the plants together in rows, they began to move away from one another, forming the same zigzag configurations that we’d seen in the previous study.
We analyzed the plants’ circumnutations and found that at any given time, the direction of the plant’s motion appeared completely independent of how it was moving about half an hour earlier. If you measured a plant’s motion once every 30 minutes, it would appear to be moving in a completely random way.
We also measured how much the plant’s leaves grew over the course of two weeks. By putting all of these results together, we sketched a picture of how a plant moved and grew on its own. This information allowed us to computationally model a sunflower and simulate how it behaves over the course of its growth.
A sunflower model
We modeled each plant simply as a circular crown on a stem, with the crown expanding according to the growth rate we measured experimentally. The simulated plant moved in a completely random way, taking a “step” every half hour.
We created the model sunflowers with circumnutations of lower or higher intensity by tweaking the step sizes. At one end of the spectrum, sunflowers were much more likely to take tiny steps than big ones, leading to slow, minimal movement on average. At the other end were sunflowers that are equally as likely to take large steps as small steps, resulting in highly irregular movement. The real sunflowers we observed in our experiment were somewhere in the middle.
Plants require light to grow and have evolved the ability to detect shade and alter the direction of their growth in response.
We wanted our model sunflowers to do the same thing. So, we made it so that two plants that get too close to each other’s shade begin to lean away in opposite directions.
Finally, we wanted to see whether we could replicate the zigzag pattern we’d observed with the real sunflowers in our model.
First, we set the model sunflowers to make small circumnutations. Their shade avoidance responses pushed them away from each other, but that wasn’t enough to produce the zigzag – the model plants stayed stuck in a line. In physics, we would call this a “frustrated” system.
Then, we set the plants to make large circumnutations. The plants started moving in random patterns that often brought the plants closer together rather than farther apart. Again, no zigzag pattern like we’d seen in the field.
But when we set the model plants to make moderately large movements, similar to our experimental measurements, the plants could self-organize into a zigzag pattern that gave each sunflower optimal exposure to light.
So, we showed that these random, irregular movements helped the plants explore their surroundings to find desirable arrangements that benefited their growth.
Plants are much more dynamic than people give them credit for. By taking the time to follow them, scientists and farmers can unlock their secrets and use plants’ movement to their advantage.
Chantal Nguyen, Postdoctoral Associate at the BioFrontiers Institute, University of Colorado Boulder
This article is republished from The Conversation under a Creative Commons license. Read the original article.
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The Knowledge
Metrolink Offers Fare-Free Rides for Earth Day 2026 Across Southern California
Metrolink offers fare-free rides for Earth Day 2026 across Southern California, encouraging sustainable travel and reduced emissions.
Last Updated on April 21, 2026 by Daily News Staff
Metrolink Offers Fare-Free Rides for Earth Day 2026
LOS ANGELES — April 22, 2026 — In a continued push toward sustainable transportation, Metrolink will once again offer systemwide free rides on Earth Day, inviting commuters and travelers to leave their cars behind and explore a cleaner way to move across the region.
A One-Day Opportunity to Ride Free
On Wednesday, April 22, passengers can board any Metrolink train — including the Arrow service — without purchasing a ticket. The initiative is part of the broader celebration of Earth Day, encouraging environmentally conscious travel choices.
The fare-free program is designed to appeal to both regular riders and first-time users, particularly those navigating Southern California’s persistent traffic congestion and rising fuel costs.
Encouraging Sustainable Travel Habits
“Earth Day is a reminder that small changes, like choosing public transit over driving one day a week, can have a meaningful impact on our environment,” said Doug Chaffee, chair of the Metrolink Board.
With gas prices continuing to strain household budgets, the agency hopes the initiative will inspire more residents to consider rail as part of their regular commute.
Regional Connections Expand Access
Metrolink’s Earth Day promotion aligns with similar efforts by other Southern California transit providers. Riders can seamlessly connect to services operated by: LA Metro and the Orange County Transportation Authority, Riverside County Transportation Commission, San Bernardino County Transportation Authority and Ventura County Transportation Commission.
These partnerships extend the reach of fare-free travel across a six-county region, making it easier for riders to explore destinations without relying on personal vehicles.
Service Adjustments and Rider Tips
Passengers should note that trains will operate on a reduced weekday schedule, implemented earlier this spring. Despite the adjustment, all Metrolink lines and station cities remain in service.
For those planning a trip:
- No ticket is required — simply board the train
- Bikes are welcome, with capacity ranging from three bikes per standard car to nine in designated bike cars
- A curated destination guide highlights attractions within walking or biking distance of stations
Environmental and Economic Impact
Metrolink is also promoting its Personal Impact Calculator, a digital tool that allows riders to estimate how switching from driving to rail can reduce greenhouse gas emissions and lower fuel expenses.
A Broader Trend in Public Transit
Fare-free transit days have gained traction nationwide as agencies look to boost ridership and promote sustainability. Southern California’s expansive commuter rail network makes it particularly well-suited for such initiatives, offering a viable alternative to one of the country’s most car-dependent regions.
Bottom Line
Metrolink’s Earth Day promotion is more than a one-day free ride — it’s a strategic effort to shift commuter behavior, reduce environmental impact, and showcase the convenience of regional rail. For Southern Californians, April 22 presents a low-risk opportunity to rethink how they travel.
Source: Metrolink
https://metrolinktrains.com/news/metrolink-goes-fare-free-for-earth-day-on-april-22
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Money Management: The Importance of Financial Literacy
You may have mastered the core subjects like math and grammar in school, but financial literacy – or understanding the basics of money management in order to help you make better financial decisions – often goes overlooked before adulthood. It’s not so much a course of study as it is a plan of action. When you understand how to earn, save, spend and invest wisely, you aren’t just building a stable future for yourself, but your family and community as well.
(Feature Impact) You may have mastered the core subjects like math and grammar in school, but financial literacy – or understanding the basics of money management in order to help you make better financial decisions – often goes overlooked before adulthood. It’s not so much a course of study as it is a plan of action.
Financial literacy in the United States has remained stagnant at generally low levels for several years, according to research from TIAA Institute and the Global Financial Literacy Excellence Center, with even lower levels among Gen Z. Yet greater financial literacy – including key aspects such as goal-setting, budgeting, saving, credit management and investing – is strongly linked to better financial outcomes, including lower rates of debt constraint and financial fragility.
While emboldening yourself to understand financial terms can be a little overwhelming at first, once you have a grasp of basic concepts you can begin to get a handle on your money and make better financial decisions. Simply put: When you understand how to earn, save, spend and invest wisely, you aren’t just building a stable future for yourself, but your family and community as well.
From nonprofit partnerships to volunteer-led programs and fee online resources, Schwab and its employees help millions of people every year build the knowledge and confidence to take charge of their financial futures by serving as board members, mentors, role models and educators.
Because financial health is a lifelong journey, the earlier people learn vital money skills, the better. That’s why the financial advisory services provider develops education programs geared toward kids that continue into adulthood, helping people no matter where they are on their journeys.
Talk Money
It’s never too early to start a conversation about financial literacy. Having teens identify goals that are important to them – such as concert tickets or a first car – can kickstart coversations about money. Working with your child (and a financial advisor, if necessary) on a plan for saving to realize those goals can serve as a jumping off point. After achieving some success, their enthusiasm may grow, which is a powerful motivator to keep saving.
Support School Initiatives and Programs
Outreach programs that empower young people to make smart financial decisions is key to a bright future. Programs like Money Matters – Schwab’s flagship financial education program utilized by the Boys & Girls Clubs of America – gives young people hands-on experience with all aspects of money and investing.
This example, and others, don’t just include program funding – they build partnerships that create impact and opportunity with national collaborations that reach more than 17 million youth annually, empowering young people with the tools and confidence to make smart financial decisions for life.
Spread the Financial Love
Championing financial literacy empowers everyone – individuals, families and communities. By serving as a board member, mentor, role model or educator to help bring financial literacy to others in your community, you can supply the tools and knowledge to lead programs that focus on giving back, empowering future generations in countless ways.
To learn more about financial literacy and find resources to empower your local community, visit SchwabMoneywise.com.
Photo courtesy of Shutterstock
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SUVs and EVs Take Center Stage at the 2026 New York International Auto Show
(Feature Impact) The 2026 New York International Auto Show is shining a spotlight on the latest in automotive innovation, from advanced technology to the growing shift toward electric vehicles. One automaker, Kia, is using the show to highlight two versatile SUVs designed to offer more space, capability and flexibility for modern drivers.
Watch this video to learn more
The all-new 2027 Kia Seltos has grown in size, offering a roomier interior with additional legroom, headroom and cargo space. It also adds a hybrid powertrain, making it the only vehicle in its class with three powertrain options. The SUV comes packed with advanced safety features, a more capable all-wheel-drive system and premium interior touches, including dual 12.3-inch display screens and an available panoramic sunroof.
The automaker is also showcasing the all-electric EV3, a compact SUV designed to make electric vehicle ownership more practical. With an estimated range of up to 320 miles, fast-charging capability and optional all-wheel drive, it balances performance, technology and everyday usability. Its intuitive features and flexible design make transitioning to electric simpler for a wider range of drivers.
Both models represent Kia’s commitment to providing options that blend capability, innovation and style. To learn more, visit Kia.com.
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