Lynn Weyer, wearing a white lab jacket and safety goggles, held an orange balloon in the Coffman Union theater.

“Have you ever wondered how they make fireworks?” the chemistry graduate student asked the audience of elementary school students and their parents.

Her assistant, an elementary school student from the audience, stood wide-eyed far from the balloon. With his arm outstretched, the assistant held the match under the balloon. It burst into green flames and the children gasped.

Elementary students and high school students saw similar chemistry experiments, as well as other hands-on math and science exhibits Saturday at Coffman Union as part of the 15th annual Family Fun Fair organized by the Institute of Technology Center for Educational Programs.

Alex Janosek, the program coordinator, said more than 600 people registered for the program. The Fun Fair targeted students in grades three through 12, their parents, and elementary school teachers. University departments and local companies and organizations that deal with math and science presented at the event.

In one room, students could make their own slime, learn about the effects of ultraviolet light, see DNA and make a cloud in a plastic bottle with the help of students from the University’s chemistry department.

Monica Foss brought her students in the Girls Excel in Math program from Cedar Park Elementary School of St. Paul to the University on Saturday to teach other children and parents how to make origami and create tessellations, a kind of puzzle.

Before coming to the event, students discussed what they wanted to teach and what kinds of words to use when instructing others, Foss said.

“The girls just plain have fun,” she said.

In another room, students studied the brain with the help of the neuroscience department’s Georgia Brier and Carrie MacNabb.

“Hi, would you like to hold a brain?” said Brier, community program specialist, to a boy.

“Mom, look at the rat brain! Look at the cow brain!” he said.

Younger kids tend to find touching a brain cool, while older kids think it’s disgusting, Brier said.

“Once they start holding it and touching it, they get really interested,” she said.

Laura Herzog, an 11-year-old from Anoka, said she liked most the chemistry demonstration in which Weyer blew up balloons. Herzog said she thinks science is fun, but she wants to be a writer when she grows up.

Exhibits for high school students included math demonstrations by University professors and a forensics presentation on bloodstain pattern analysis by the state crime lab.