Physics professor sheds light on LASERS to high school students

Cahokia High School students edged closer to catch a glimpse of the multiple laser beams emitted back and forth between two mirrors which shone through the smoke.

Prfofessor Glassman looks on as Cahokia High School students engage in a demonstration that reveals an aspect of LASERS using a lamp light and magnifying glass. Photo by Theresa San Luis

This was among numerous demonstrations that physics professor Jack Glassman shared from his more than 30 years of knowledge of giant LASERS (Light Amplification by Stimulated Emission of Radiation) Thursday at Cahokia High School. This was the second of three lectures within three weeks as part of the Gateway Teen Science Cafe program.

Teen Science Café is funded by the National Science Foundation with the purpose of “starting conversations with prominent leaders in their fields [of science and technology], while providing a non-intimidating, relaxed environment,” according to the Gateway Teen Science Café website.

At Cahokia High School, Glassman reflected on his career and said he has been active in designing giant lasers including a trillion-watt system in Nevada and a proposed “exawatt” (a quintillion watts) system that is currently being designed in Texas.

Ladonna Feldhake, a chemistry teacher at Cahokia High School, said she appreciated the opportunity her students gained from Glassman.

“They get to see a real live practicing scientist talk to them in a way that’s exciting and understandable,” Feldhake said. “It sparked new interests and introduced possible career paths.”

Sean Herberts, regional director for Gateway Teen Science Cafes and Outreach Coordinator for the Science, Technology, Engineering and Mathematics Center (STEM) of SIUE, said the series of talks are intended to “make science accessible for teens.”

Glassman’s presentation style, according to Herberts, makes him a “great fit” to present complex science in an informal setting.

“He makes complicated subjects accessible to youth through humor, anecdotes and clear imagery,” Herberts said.

According to Glassman, through a phenomenon called resonance– similar to strings on musical instruments vibrating each other when played—the process of making a laser starts with two atoms that are “smacked” or excited that “ring each other.”

“The light from the two atoms emit light,” Glassman said. “One hundred billion, billion atoms ringing together…put these in a box created by two mirrors (mirrors make a really good box for light)…and the light bouncing back and forth gets amplified by the atoms creates the laser.”

Glassman had students focus a beam of light through a magnifying glass to demonstrate part of how lasers work. He also had students swing pendulum balls to demonstrate period and frequency of lasers that have pulses and resonate.

Annamary King, a mathematics teacher at Cahokia High School, said her students enjoyed the interactive nature of the presentation.

“Because this is an informal environment focused on science, the café offers a unique platform for teens to be social,” King said. “Teen Science Cafés allow teens to explore science, technology, engineering and math with friends in a casual setting. More importantly, the series offers exposure to new fields and applications of science and math that they might not receive otherwise.”

Glassman said speaking to students is fulfilling.

“Preparing for this is a fair amount of work, but it’s an opportunity to encourage high school age students to pursue careers in STEM fields,” Glassman said.

According to Glassman, students who have attended his free, interactive lectures have been “highly engaged with fairly impressive questions and a gratifying level of understanding.”

Glassman’s first lecture was held Feb. 20 before roughly 50 students at the Junior Academy of Science in St. Louis.

His third lecture will take place at the St. Louis Science Center’s Taylor Center in St. Louis from 5:30-7:30 p.m. on Thursday, March 6.

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