Award-winning geologist Richard Alley explained to children how their inventions and ideas can fix global warming issues at STEMfest Saturday.

Alley presented a map of the world, blank aside from a pink spot in the middle of Africa. That point in Africa, he said, would be all the land it would take to supply the world’s energy needs if the point were filled with wind turbines. He stressed that with the creativity and knowledge that the newest generation could bring, the space could be even smaller or there could be a way to harvest energy more efficiently.

“Without science and engineering, we’d have nothing,” Alley said. “Look at what has happened in the past 100 years with technology; imagine what we’ll do in the next 100.”

The Convocation Center was filled with attendees coming to see speakers talk about the major fields in science, technology, engineering and mathematics. Taking precedence at Saturday’s STEMfest was a simple stage with a few projectors that featured a constant stream of professionals, including Alley, speaking about their fields, whether it was nuclear power, physics or the environment.

With their booths lining the walls and filling the court, dozens of professionals from all branches of these fields came to show what they do in their field of STEM and how it benefits the world. The representatives included the Society of Women Engineers, aerodynamic studies, audiologists showing how the ear works and machinists playing catch with their remote control creations.

Mike and Wendy Carter brought their children, Alison, 6, and Owen, 8, of Chicago, to witness the event Saturday.

“I teach an after-school STEM program,” said Wendy Carter. “So I came here to keep up with what’s new and see what I can teach my students, along with my own kids.”

Timothy Smith, 10, from DeKalb, said he “really [liked] how everyone has cool stuff to share, and there’s lots of stuff to do.”

Freshman engineering major Simar Grewal said he was at STEMfest for a school-based engine efficiency group that has a goal to create car engines capable of going further using less fuel. At last year’s STEMfest, the group presented a car the members designed that went nearly 1,000 miles on 1 gallon, Grewal said.