Five-year-old Sarah Chitavi of Des Plaines can easily rattle off what she learned Saturday during the Family Science Expo, held at the Des Plaines Public Library.
Thanks to a demonstration from the Structural Engineers of Illinois, Sarah now has a basic understanding of why skyscrapers, including the John Hancock Center and Willis Tower, use steel bracing shaped like an "x" all over the building -- to keep it from moving in the wind and falling down.
Robert Johnson, who handles public relations for the Structural Engineers of Illinois, built models of the skyscrapers and used string to demonstrate the steel bracing. He showed how the string stabilizes and anchors the model by having a child blow on it.
"All of this is to show kids and their parents how buildings stand up and fall down," Johnson said.
The organization was among 13 groups that set up engineering-related exhibitions inside the library. The event, now in its fifth year, ran from noon to 4 p.m. and also let children design, build and test model bridges and ride a stationary bike generator that can pump water, spin a globe and power a record player. Between 300 and 500 people were expected to attend.
The aim of the event was to expose boys and girls to science at a young age in hopes they'll later pursue careers in the field, said Stephanie Spetter, head of the library's youth services department.
This would ensure there's a large pool of scientists in America and employers could avoid the need to recruit them from other countries, she said.
"We want to grow our own students so we have to start them young," she said.
Besides learning about building stability, Sarah Chitavi learned how to count money with a machine and the value of certain coins.
But her favorite part was the bit about the skyscrapers.
"I like making buildings and towers and castles out of blocks," Sarah said.
While Sarah has yet to visit Willis Tower or the John Hancock building, her mother, Salome Chitavi says Saturday's events inspired her to build on what her daughter learned.
"Now there's an excuse to take her," Chitavi said.