Science for the day

The New York Times has an article by David Frank and James Gorman about studying flame:

Among the enduring mysteries of science are the nature of the universe, the origin of life, and how to get the attention of students.

Victor Miller and his colleagues in the engineering school at Stanford University have not made headway on the first two. To be fair, they are not even working on them. But as to students: how about firing a laser at a methane bubble to set it aflame?

Lighting up methane is not exactly science, but if you record the result at ten thousand frames a second with a technique called schlieren imaging, which the students themselves have to master, and then require them to figure out how to compute the speed at which the flame grows based on the video, you’re ready for graduate students at Stanford.

Dr. Miller, a researcher at Stanford; Chris Goldenstein, another researcher; and Valerie Troutman, a Ph.D student, recently worked with graduate students in engineering at Stanford to produce and analyze just such videos.

The videos, like one of a match firing up that was created last year by Miller and others, are in black and white, and the technique requires very exact placement of the camera, light source, and mirrors to capture differences in density among the turbulent hot gases as the flame grows.

Miller said he and his colleagues were preparing for a lab course in “optical diagnostics and spectroscopy” in which graduate students must use schlieren imaging when they came up with the plan. Last year, Miller had done the match video for this course and it won an award at a meeting of the Division of Fluid Dynamics of the American Physical Society. It was also featured in ScienceTake.

This time, he wanted to do something different, and Miller said that Goldenstein was the one who suggested, “we should fill up bubbles with methane and light them”. He had seen it done before, and Miller thought it seemed like a great idea. So they supervised the students setting up a camera, a laser, a light source, and mirrors at exactly the right positions and angles, which is the difficult part.

The students loved it, Miller said. Then, using the video, the students had to figure out a way to measure the flame speed. He sees a wider use for the technique, perhaps with less complicated analysis.

“This could be a really fun thing to have in K-12 classrooms,” he said. He said that two smartphones could serve as camera and light source. They wouldn’t record at the same high speed as the camera he uses, but some smartphones have slow-motion abilities.

And he says a 3-D printer could be programmed to make frames to hold the mirrors and cameras, solving the problem of getting exactly the right angles.

Anyone want to go back to middle school?

and a NASA video about the Sun:

Rico says the world is infinitely more amazing than we can comprehend...