It happened around 1:00 p.m. inside a science classroom at Eastern Regional High School on Laurel Oak Road.
16-year-old Austin Friedent tells Action News his physics teacher was demonstrating some sort of chemical reaction when the chemicals spilled onto the table and erupted into flames.
Friedent says the teacher was starting the demonstration after a successful first trial with less potent chemicals.
"He was doing a second trial and as he poured it on the desk, the whole desk went up in flames. The whole hallway went up in smoke," Friedent said.
A school spokeswoman tells Action News junior Ari Goldovsky suffered burns. He was rushed to Cooper Medical Center before being taken to St. Christopher's Hospital for Children where he is listed in good condition.
School Principal Robert Tull said the teacher and five other students were taken to Virtua Hospital where they have been treated and released.
Other students tell Action News the fire alarms in the school went off twice. At first, the students we spoke with thought it was a drill until they saw the fire trucks arrive at the school.
At this point, there is no indication on what kinds of chemicals were used during the demonstration.