The long history of African-Americans on the Delaware River is traced in a new exhibition at the Independence Seaport Museum in Philadelphia. The interactive show asks visitors to physically empathize with racial history.

"Tides of Freedom" is a series of rooms; the first represents the arrival of Africans to Philadelphia as slaves. The museum made a simple wooden platform. When you stand on it, your weight triggers an audio recording of an auction caller.

"This is the auction block," said curator Tukufu Zuberi. "Here, someone is purchasing you."

Zuberi is accustomed to audience engagement: he's a host of the PBS show, "History Detectives," and the chair of the sociology department at the University of Pennsylvania. He designed this exhibition to dip and rise from from low to high points of African-American history on the Delaware River, spanning slavery, emancipation, fisheries subject to Jim Crow laws, and World Way II shipyards.

When Zuberi began planning this exhibition, the staff of the Seaport museum assumed they would have to borrow items from outside collections. The museum was founded as a repository of the region's maritime history, not its racial history. Its archive records had very little related specifically to African-Americans.

"I'd spent a lot of time in dusty museum archives, and I always find these archive basements contain valuable materials," said Zuberi. "The Seaport Museum was not an excpetion."

With some digging, museum archivists discovered they had a "waste book," an accounting ledger that recorded all commerical transactions on the warf. Working on a hunch, Zuberi combed through the book and discovered 63 entries where traders bought and sold African slaves. Staff curator Craig Bruns says it's the only document of its kind in Philadelphia.

With some creative interpretation and dogged research, the Seaport Museum managed to present 300 years of African-American history on the Delaware using mostly it's own collection. "We were able to find some absolute jewels," said Zuberi.

The exhibition touches on how the river was used for the Underground Railroad, and for transporting African-American troops during the Civil War.

During World War II, the Sun Shipbuilding Company in Philadelphia opened one of its yards - Yard 4 - to black workers only. Sun hired Emmett Scott, a former assistant to Booker T. Washington, to manage the segregated yard.

"Emmett Scott is saying, 'let's do this. It will create 9,000 jobs for Negroes,'" said Zuberi. "On the other hand, people from NAACP were saying, 'this is crazy - we would rather see 10,000 African-Americans without jobs than 9,000 working in a segregated space. This is what we're fighting against.'"

For years, thousands of African-Americans made a decent living building ships that were instrumental in winning the war. "But this was an instance of last hired, first fired," said Zuberi. "After the war, the yard was shut down. Most African-Americans who worked for Sun were fired."

The final room of the exhibition can be entered via two doorways, marked "Colored Only" and "White Only." Visitors are put on the spot: to go forward they have to decided which door they will walk through.

"We're asking you to get involved in this exhibit as a way to help you understand it, by going through some of what the people who experienced these social processes went through," said Zuberi. "How did they feel? Can you find a space where your identifying with them is not insulting to you?"

"Tides of Freedom" opens this weekend and runs until 2015. The next exhibition in the "River of Freedom" series has not yet been determined.