James West, a bona fide rock star of science and technology, explained to the rapt group of young students assembled around his table that African drum communication was a model for the cellphone.

Just as voices are transmitted from tower to tower before they reach their destinations, drum messages traveled from drummer to drummer, said West, 85, a professor of engineering at Johns Hopkins University.

Rafi Mills, 12, was impressed.

"I didn't know in Africa they had drum telephones," said Mills, an eighth grader at Masterman, a magnet school in Center City. "Just the creativity of that is kind of amazing."

Mills was among a group of about 300 students who filled the Franklin Institute on Saturday for the Color of Science, a program designed to highlight the contributions of men and women of color to science, engineering, technology, and math.

The two-day event, which started with a panel discussion Friday, featured 11 scientists stationed throughout the museum near exhibits related to their fields of study. During a two-hour tour, elementary and middle school students walked from stop to stop for demonstrations and question-and-answer sessions.

This year's theme focuses on African American men in STEM. It's a response to President Obama's My Brother's Keeper initiative, which aims to address issues facing young men of color.

"Scientists come in all shapes, shades, races, and religions," said Frederic Bertley, the institute's senior vice president of science and education. "We want to emphasize that scientists are a diverse portfolio of men and women who are living and breathing and who have contributed to science in multiple ways."

Bertley developed the program six years ago, weary of repeatedly hearing the name Albert Einstein when he asked students if they knew of a scientist.

So each year, Bertley, who has a doctorate in immunology, gathers a diverse group of STEM professionals to meet students who move from station to station and get their Color of Science "passports" stamped at each table. The program has been held in other cities including Atlanta, San Diego, and Washington.

On Saturday, Rocio Garay, a technology engineer with Braskem America, talked about the polymer resin beads used to make bumpers and bottle caps. Larry Gladney, a physics professor and associate dean at the University of Pennsylvania, demonstrated the power of electricity to move aluminum pans and cheerleader pom-poms.

West, the award-winning developer of microphone technology used in most cellphones, displayed a variety of phones and microphones.

He told the students that when he was a child, he was fascinated by Dick Tracy and the comic-book character's two-way wrist radio. The interest helped motivate West to study technology.

In an interview between sessions, West said he wanted to be a real-life role model and motivator.

"I'm here because it's important for our young people to see people that look like them and are doing things in STEM," West said.

Programs such as the Color of Science and others that focus on minority participation may be working.

When Mills was asked to name a scientist, Einstein was third on his list.

Neil deGrasse Tyson, who is black and Puerto Rican, was first.