Belot could not be reached for comment, and chemistry department Chairman Patrick Dussault was out of town Monday.
Bartling said UNL administrators and the police are still trying to figure out what exactly happened during the class, and she wouldn't speculate on Belot's behavior or motivation for giving the explosives to students. Administrators also are looking into whether the chemistry department has more explosives on hand, she said.
Perlman said to his knowledge, this situation has not happened before at UNL.
"I don't think one has to do much to alert people that this is not the kind of behavior that is expected of the university," he said, adding that he didn't yet know the full facts of the situation.
Franco and Perlman both said they were proud of the students who already returned some of the explosives, and they asked the remainder to follow suit.
Students who turn the devices over to the university will not be subject to disciplinary action, Franco said.