The gasps were audible as Aisha Dickerson casually tossed a cup full of liquid nitrogen onto the carpeted floor of the Chelsea City Hall.

Seconds later, the audience of senior citizens had smiles on their faces as the liquid instantaneously evaporated into a misty, swirling gas.

Dickerson, the outreach coordinator for Birmingham’s McWane Science Center, was in Chelsea Friday to do a “Really Cool Science for Seniors” program.

She used liquid nitrogen to show the differences among liquid, gas and solids with different experiments.

Dickerson said she really enjoys working with senior citizens because they’re just as curious as children are.

“They’re always so interested,” she said. “They’re all still into learning and seeing things they’ve never seen before. It’s kind of cool to realize they haven’t seen everything.”

In one of Dickerson’s experiments, she showed how fast liquid nitrogen evaporates by pouring it into a Coke bottle and putting in a cork. Within seconds, the cork popped, pushed out by the building pressure of the gas.

In another experiment, she called for a volunteer, who ate a cracker that had been dipped into the nitrogen. Gas immediately began to stream from her nose and from her laughing mouth. The point was clear: if liquid nitrogen needs to expand, it will go through any available opening.

Audience member Gene Matthews said he enjoyed the spectacle.

“I learned a lot about the liquid nitrogen. I never saw that before,” he said.

Matthews said while it was his first experience with liquid nitrogen, he has seen plenty of science at the McWane Center.

“I take my grandchildren down there,” he said. “They enjoy it. They wear us out.”

Dickerson said while the McWane Center often does programs for schoolchildren, it’s relatively rare for them to do programs for senior citizens. In fact, McWane usually only does programs for senior citizens in Shelby County, she said.

Dickerson said the programs are good for the community because they spread knowledge to those who want it.

“We do so many programs, and the best part is to see the hands-on experience,” she said. “They get it better. They hold on to it and never forget it.”