Who hasn’t wanted a tractor beam at one time or another? The notion that beaming a ray of light at something would allow you to bring it closer is very appealing. And, if you’re willing to settle for a particle, you could have  a tractor beam in the near future according to scientists in Singapore. From the May 23, 2012 news item on Nanowerk,

Tractor beams are a well-known concept in science fiction. These rays of light are often shown pulling objects towards an observer, seemingly violating the laws of physics, and of course, such beams have yet to be realised in the real world. Haifeng Wang at the A*STAR Data Storage Institute and co-workers have now demonstrated how a tractor beam can in fact be realized on a small scale (see paper in Physical Review Letters: “Single Gradientless Light Beam Drags Particles as Tractor Beams” [behind a paywall]). “Our work demonstrates a tractor beam based only on a single laser to pull or push an object of interest toward the light source,” says Wang.

Coming up in the description of just how Wang’s tractor beam works is my second reference to Albert Einstein today (in the earlier May 23, 2012 posting: Teaching physics visually), form the news item on Nanowerk,

Based on pioneering work by Albert Einstein and Max Planck more than a hundred years ago, it is known that light carries momentum that pushes objects away. In addition, the intensity that varies across a laser beam can be used to push objects sideways, and for example can be used to move cells in biotechnology applications. Pulling an object towards an observer, however, has so far proven to be elusive. In 2011, researchers theoretically demonstrated a mechanism where light movement can be controlled using two opposing light beams — though technically, this differs from the idea behind a tractor beam.

Wang and co-workers have now studied the properties of lasers with a particular type of distribution of light intensity across the beam, or so-called Bessel beams. Usually, if a laser beam hits a small particle in its path, the light is scattered backwards, which in turn pushes the particle forward. What Wang and co-workers have now shown theoretically for Bessel beams is that for particles that are sufficiently small, the light scatters off the particle in a forward direction, meaning that the particle itself is pulled backwards towards the observer. In other words, the behaviour of the particle is the direct opposite of the usual scenario. The size of the tractor beam force depends on parameters such as the electrical and magnetic properties of the particles.

There aren’t too many real life applications for a tractor beam of limited power but the lead scientist, Wang, does suggest it could be helpful in diagnosing malaria at the cellular level.

Art/science news  is usually about a scientist using their own art or collaborating with an artist to produce pieces that engage the public. This particular May 23, 2012 news item by Andrea Estrada on the physorg.com website offers a contrast when it highlights a teaching technique integrating visual arts with physics for physics students,

Based on research she conducted for her doctoral dissertation several years ago, Jatila van der Veen, a lecturer in the College of Creative Studies at UC [University of  California] Santa Barbara and a research associate in UC Santa Barbara’s physics department, created a new approach to introductory physics, which she calls “Noether before Newton.” Noether refers to the early 20th-century German mathematician Emmy Noether, who was known for her groundbreaking contributions to abstract algebra and theoretical physics.

Using arts-based teaching strategies, van der Veen has fashioned her course into a portal through which students not otherwise inclined might take the leap into the sciences — particularly physics and mathematics. Her research appears in the current issue of the American Educational Research Journal, in a paper titled “Draw Your Physics Homework? Art as a Path to Understanding in Physics Teaching.”

The May 22, 2012 press release on the UC Santa Barbara website provides this detail about van der Veen’s course,

While traditional introductory physics courses focus on 17th-century Newtonian mechanics, van der Veen takes a contemporary approach. “I start with symmetry and contemporary physics,” she said. “Symmetry is the underlying mathematical principle of all physics, so this allows for several different branches of inclusion, of accessibility.”

Much of van der Veen’s course is based on the principles of “aesthetic education,” an approach to teaching formulated by the educational philosopher Maxine Greene. Greene founded the Lincoln Center Institute, a joint effort of Teachers College, Columbia University, and Lincoln Center. Van der Veen is quick to point out, however, that concepts of physics are at the core of her course. “It’s not simply looking at art that’s involved in physics, or looking at beautiful pictures of galaxies, or making fractal art,” she said. “It’s using the learning modes that are available in the arts and applying them to math and physics.”

Taking a visual approach to the study of physics is not all that far-fetched. “If you read some of Albert Einstein’s writings, you’ll see they’re very visual,” van der Veen said. “And in some of his writings, he talks about how visualization played an important part in the development of his theories.”

Van der Veen has taught her introductory physics course for five years, and over that time has collected data from one particular homework assignment she gives her students: She asks them to read an article by Einstein on the nature of science, and then draw their understanding of it. “I found over the years that no one ever produced the same drawing from the same article,” she said. “I also found that some students think very concretely in words, some think concretely in symbols, some think allegorically, and some think metaphorically.”

Adopting arts-based teaching strategies does not make van der Veen’s course any less rigorous than traditional introductory courses in terms of the abstract concepts students are required to master. It creates a different, more inclusive way of achieving the same end.

I went to look at van der Veen’s webpage on the UC Santa Barbara website to find a link to this latest article (open access) of hers and some of her other projects. I have taken a brief look at the Draw your physics homework? article (tir is 53 pp.) and found these images on p. 29 (PDF) illustrating her approach,

Figure 5. Abstract-representational drawings. 5a (left): female math major, first year; 5b (right): male math major, third year. Used with permission. (downloaded from the American Educational Research Journal, vol. 49, April 2012)

Van der Veen offers some context on the page preceding the image, p. 28,

Two other examples of abstract-representational drawings are shown in Figure 5. I do not have written descriptions, but in each case I determined that each student understood the article by means of verbal explanation. Figure 5a was drawn by a first-year math major, female, in 2010. She explained the meaning of her drawing as representing Einstein’s layers from sensory input (shaded ball at the bottom), to secondary layer of concepts, represented by the two open circles, and finally up to the third level, which explains everything below with a unified theory. The dashes surrounding the perimeter, she told me, represent the limit of our present knowledge. Figure 5b was drawn by a third-year male math major. He explained that the brick-like objects in the foreground are sensory perceptions, and the shaded portion in the center of the drawing, which appears behind the bricks, is the theoretical explanation which unifies all the experiences.

I find the reference to Einstein and visualization compelling in light of the increased interest (as I perceive it) in visualization currently occurring in the sciences.