Catapults flinging marshmallows, homemade lip gloss and mesmerized children — that was the scene at North Grand Mall on Saturday for Iowa State University Engineering and Community Day, as 13 different engineering student groups took to the mall’s atrium with displays and activities.

“We’ve done it for nine years,” said Bonnie Johnson, marketing manager for North Grand Mall. “I believe it started around engineering week.”

Activities range from learning about scientific principles to making structures.

“They construct things with gumdrops and spaghetti noodles,” Johnson said.

“Last year I brought my son out — he was 4 at the time, and he loved it.”

The Institute of Electrical and Electronics Engineers and Eta Kappa Nu showed visitors how to build speakers out of paper plates, the Cyclone Power Pullers had a one-quarter scale tractor on display and Material Advantage demonstrated how to make oobleck — a semi-liquid, semi-solid substance — out of corn starch and water.

For ISU students, it’s a way to spread the word about the College of Engineering, Iowa State and what it means to be an engineer.

“Our goal is just kind of to outreach to the community,” said Austin Laugen, freshman in computer engineering and vice president of outreach for Engineering Student Council, which helped organize the event with mall staff.

In addition, the mall hosted other community booths as well, such as a “Geek the Library” booth.

“Two times a year we do that,” Johnson said. “We invite all sorts of nonprofit groups.”

Johnson said that the event is a great way for the mall to give back to the community that supports it. And it increases traffic, too.

“It brings people out to the mall, which is always a good thing for us,” she said.

Laugen said that he did generate some adult interest in the displays and community members asking what the displays were for, but that for the most part, his audience consisted of parents with their children, many of whom came specifically for the event.

“It’s been a lot of little kids,” Laugen said Saturday morning. “I’m hoping maybe later we get some older kids — maybe when they wake up.”