April 26, 2007

NSLS Sons, Daughters Uncover Mysteries of Diffraction

About 30 children of NSLS users and staff accompanied their parents to the Lab on April 26 to learn about light sources and the importance of diffraction studies to the science performed on the experimental floor. As part of the national “Take Our Daughters and Sons to Work Day,” the children first gathered in the NSLS seminar room, where they heard a brief safety talk by NSLS Safety Manager Andrew Ackerman.

Afterward, NSLS scientist Marc Allaire explained that the facility produces many types of light, from infrared to x-rays, and that this light has applications in fields such as electronics, catalysis, microscopes, and medicine. The children then learned to visualize light like a wave in the ocean. When a rock or some other object disrupts the wave’s motion, ripples are produced as the result of diffraction, Allaire explained. He then demonstrated that diffraction also happens with light by reflecting a ray of sunlight from a window onto a CD to produce a rainbow on the room’s ceiling.

Participants in the 2007 “Take our Daughters and Sons to Work Day” at the NSLS.

Next, with the assistance of NSLS scientists Lisa Miller, Syed Khalid, and Allaire, as well as User Administrator Kathy Nasta and NSLS Science Writer Kendra Snyder, the children were divided into groups and given the chance to perform their own diffraction experiment with a red laser pointer and a transparent film containing fine black and white patterns. First, the children used microscopes to study the differences between the 12 patterns, which included dots, lines, and zigzags, all with different sizes and spacing. Then, while aiming at one of the room’s walls, they shined the laser light through the images to reveal diffraction patterns varying from single lines of spots to complex two-dimensional grids. After regrouping, the children answered a series of questions about the experiment. Allaire explained that diffraction patterns depend on the shapes and spacings of the objects, and that NSLS scientists use this method to study a multitude of materials in x-ray diffraction experiments.

The children then canvassed the experimental floor looking for diffraction beamlines. After quizzing numerous scientists and even getting tours of a few hutches, they found the answer: more than 30 beamlines use this x-ray technique to look at samples such as proteins, soil, and magnetic materials. Once they were back in the seminar room, the children performed one more activity related to the most popular diffraction material – protein crystals. Using multicolored gumdrops as atoms and toothpicks as bonds, the children built their own crystals ranging from simple cubes to much more complex structures – a perfect pre-lunch snack.

ARTICLE BY: Kendra Snyder