Solving the Puzzle
Physics professor Ben Evans works to decipher unanswered scientific questions.
If physics is all about understanding the simplest bits of everything, then one particularly fiddly bit of everything turns out to be magnetics. Magnets feel simple, which is endearing – but I’ve found they are delightfully, devastatingly obtuse, and they are a puzzle I fear I’ll never solve. And I’ve always been one for puzzles.
It’s lucky for me, then, that magnetics has turned out to be useful in so many ways. Over the past decade, I’ve been working on ways to use magnetics to treat cancers and to resolve infections, to study cells and tug on single molecules, to build robots both micro and macro, to mimic microbiology and to enhance medical diagnoses. As a scientist, I value these real-world applications of fundamental principles, and I enjoy exploring interdisciplinary synergies – physics in biology, in chemistry, in medicine. But I admit that none of this keeps me up at night, neither the connections, nor the novelties, nor the ends. I don’t care for them like I should. What drives me is simpler: For me, it’s the puzzle. Like many physicists, my motivation is the simplest version of “why?” and my passion is for unanswered questions.
This is why last summer I spent a whole month reading – really, obsessively poring over (and over) – academic articles on the physics of balls falling through a fluid near a wall. Falling balls are not a particular interest of mine, but I have a question, and that question has an answer. There’s definitely an answer, and it’s somewhere in this confluence of papers. Somewhere. I go back and forth, manuscript to manuscript, re-reading bits I could see in my sleep. I get motion sickness from all the back and forth, and I imagine a deep grinding pain somewhere mid-brain, behind and between the eyes, while I wear mental ruts of well-tracked thoughts. If A then B; if B then C, if… where is the paper on C? I find success and sleep well one night, but the next morning success shows itself to be a herring, and I start over at B. Weeks, this is. More papers, more models, more mathematics, squeezing myself into a new set of definitions (theta is phi? r is a?) and finally, finally, I understand the question.
The answer, it turns out, is in an unpublished appendix held by a dead scientist. But a publisher finds hardcopy in a file cabinet and scans it back into the 21st century. It connects my dots, and another piece of reality slips into place in my head, and it fits. Now I can publish and sleep.
If physics is all about understanding the simplest bits of everything, then one particularly fiddly bit of everything turns out to be magnetics. Magnets feel simple, which is endearing – but I’ve found they are delightfully, devastatingly obtuse, and they are a puzzle I fear I’ll never solve. And I’ve always been one for puzzles. It’s lucky for me, then, that magnetics has turned out to be useful in so many ways. Over the past decade, I’ve been working on ways to use magnetics to treat cancers and to resolve infections, to study cells and tug on single molecules, to build robots both micro and macro, to mimic microbiology and to enhance medical diagnoses.
Is there a point? Sure: The falling-ball-near-a-wall lets us build swimming magnetic micro-robots, which can (could) deliver drugs inside the body, transport cells and constitute a tool that (eventually) makes life better for everyone. Other things – the sub-microscopic rust which heats up, the magnetic flippers and flappers which make valves, pumps, whole systems for microscopic manipulation – lead to similar ends. Those ends motivate my work for others.
For me, it’s the niggling, dangling, loose end of not understanding something which should be understood that grabs hold of my whole self and makes it work through to the end. It’s the only thing that makes me my best. It’s not that I hope to impose order on the universe – not at all; nature is fit and finished. It’s the universe imposing order on me, so I don’t track with untruths and I fall in more deeply with everything that is not me. And in falling in, I understand more because it’s all the same show.
I teach because I want others to see the same, and to learn to answer their own questions. In physics, we seek to understand the only set of rules that applies to everything and is never broken. Who wouldn’t want to learn? Yet so many don’t because they haven’t been shown the beauty, the elegance, and haven’t been made to experience themselves as a part of the system. I lead them with bits and pieces and encourage them to engage and grasp at the whole. Most everyone leaves with a deeper understanding, or at least a deeper appreciation for the way the world works, but some catch on and need to know more. Those students will never stop asking why, and they’ll turn into physicists.
Why? Because the best thing to understand is everything, and because if you want modern miracles, then these are places to start: with unanswered questions, with little bits of rust and a couple of magnets, and with the motion of a ball falling through a fluid near a wall.
Associate Professor of Physics and Incoming Director of the Lumen Prize
Joined Elon's Faculty
- Ph.D., Physics, University of North Carolina at Chapel Hill
- M.S., Physics, University of North Carolina at Chapel Hill
- B.S., Physics, Rhodes College
I am primarily interested in applying tools from micro- and nano-scale physics to explore questions of biological interest. My current work is in the development of magnetic polymers for a variety of biomedical applications, ranging from sensors and actuators to cancer therapeutics and medical diagnostics. Specific interests include: nanotechnology, biotechnology, magnetic nanoparticles, polymers, colloids and composite materials, magnetic hyperthermia, drug delivery, biosensors and microfluidics.
Recent scholarly works:
Non-monotonicity in the influence of nanoparticle concentration on SAR in magnetic nanoparticle hyperthermia. Journal of Magnetism and Magnetic Materials, v 456, 559-565, November 2018.
Chained Iron Microparticles for Directionally Controlled Actuation of Soft Robotics. Applied Materials and Interfaces, v 9, 11895-11901, March 2017.
Magnetic microkayaks: propulsion of microrods precessing near a surface by kilohertz frequency rotating magnetic fields. Nanoscale, v 9, 3375-3381, February 2017.
Magnetically Responsive Negative Acoustic Contrast Microparticles for Bioanalytical Applications, ACS Applied Materials and Interfaces, v 8, 25030-25035, September 2016.
High-permeability functionalized silicone magnetic microspheres with low autofluorescence for biomedical applications. Materials Science and Engineering: C, v 62, 860-869, May 2016.
Heating Efficiency in Magnetic Nanoparticle Hyperthermia, Journal of Magnetism and Magnetic Materials, v 354, 163-172, March 2014.
PHY397/398: Research Methods
PHY221/222: University Physics
PHY101: Conceptual Physics
PHY105: Physics of Sound