L. Mahadevan

The Physics of Everyday Life

Like a slow-motion release of a firework, a flower’s bud bursts forth into a delicate display. Looking at a bouquet at the florist, you might never ask how the intricate petals, stems, and stigmas, each contained in a green orb the size of a gobstopper, emerged perfectly unfolded without the slightest rip.

SEAS's Lakshminarayanan Mahadevan (Maha for short), Gordon McKay Professor of Applied Mathematics and Mechanics, has not only posed the question, but is trying to solve countless others like it. Using mathematics to understand how materials move and behave, he places particular emphasis on phenomena visible to the naked eye and closely tied to experiments or experience.

He’s explored the way honey coils (important for geologists who study the flow of molten rock within the Earth), why insects can adhere to surfaces (leading to the creation of new types of adhesives), how hair coils on water (helpful in understanding the principles of self-assembly), and the way fabrics fold and wrinkle (providing insight about the spiky surface of a diseased red blood cell).

“I find joy in discovering the sublime in the mundane,” says Maha, who recently relocated from one Cambridge (England) to another (Massachusetts). “I try to uncover explanations for everyday events that are easily seen but not well understood.

They typically turn out to be more relevant than I first imagined.” Think again about the complexity of the flower as you recall how you’ve struggled to fold a map without tearing, or at least swearing. Within the blooming process lies what Maha calls a theory for “self-assembled origami.”

The bud can unpack its suitcase and iron its clothes without the help of even a finger. “Natural systems offer a rich arena to learn about the interplay between geometry and physics in the real world. Folding is not just for flowers, but critical to our very existence. It happens in our tightly bound-up DNA,” Maha points out.

Moreover, stopping to smell (and study) the roses might someday help with creating self-assembling nanostructures, one of the most critical components of the emerging field of nanotechnology. Maha’s dark, vibrant eyes flit behind large round glasses that reflect the light in his sizable, but test tube–free third floor office of Pierce Hall. In his experience, you don’t necessarily need a lab or complicated devices to do meaningful experiments and research.

“Why struggle to find something worth studying when you have quick access to rich events, like how a flag flutters, that you can easily play with? Being able to radically change parameters – a light breeze versus a strong wind – without losing the effect is ideal for experimentation.”

With today’s emphasis on rapid innovation, supermarket science (creating volcanoes with baking soda) and everyday experimentation (looking out the window rather than at an LCD monitor) may seem passé. Yet Maha’s hands-on experimentation, most of which could have been done by true renaissance engineers, does not imply that such research is any less difficult or fruitful. Rather, he acknowledges that good science can arise from simple observation.

Not surprisingly, Maha’s “mundane” investigations cross – if not leap – over traditional boundaries in physics, math, engineering, and biology. In fact, figuring out what comes naturally requires continuous collaboration with scientists from many disciplines at Harvard, MIT, and throughout the world. Maha emphasizes that his dedicated students – “the lifeblood of my enterprise” – deserve as much credit as he does for illuminating the physics of everyday life.

“Ultimately, any robust event is likely to be interesting for its own sake, since it explains something essential about how the world works,” observes Maha. And he’s not alone in appreciating such rough magic. In regard to Maha and his colleagues’ celebrated theory of how wrinkles form, Nature editor Philip Ball wrote, “It is humbling to find in a high-powered journal like Physical Review Letters that we have limped along for years without an understanding of what controls the wavelength and amplitude of wrinkling in a sheet. There’s plenty still to be learned from the $20 experiment.”

Maha explains his passion for research by referencing a classic tale about the young Krishna, from the Bhagavata Purana. The child, an incarnation of the Hindu god Vishnu but brought up incognito by foster parents, had a reputation for mischief.

One day, friends accused Krishna of eating dirt. Dismayed, his mother demanded an explanation. Krishna denied the charge, saying “I have not eaten dirt. They are all lying!” To force a confession, his mother told him to open wide. But Krishna, to avoid being caught in a lie, played a trick.

Instead of muddy teeth, he revealed the entire universe to her – the earth, the stars, and the elements of all creation. And then, to
keep his cover, Krishna quickly cast a spell of forgetfulness over her to clear her memory.

“One way to look at the story,” Maha explains, “is to understand that meaning and the answers to the deepest questions can be found in the stuff all around us. Science is about looking for connections and finding joy in discovery itself.”

Lucky for us, Maha – unlike Krishna’s mother – has not forgotten where the universe lies, but continues to look deep inside simple things, like flowers or dirt, to pull out the profound.