Lawrence first-grader Gavin Kirk may be hardheaded about some things, but he can’t challenge his own research findings.

His plan was to develop a project for the Douglas County Science Fair that demonstrated he didn’t need to wear a helmet while riding his bicycle. To test, he dropped to the ground chicken eggs protected by padding typically found in bike helmets.

Gavin Kirk, 6, left, a first-grader at Schwegler School, looks over Douglas County Science Fair exhibits after setting up his own bicycle helmet safety project for the fair. With Gavin Wednesday at the fair are his mother, Michelle Kirk, and sister, Caroline, 1, at the Douglas County 4-H Fairgrounds, 21st and Harper streets.

If eggs cracked, Kirk reasoned, the value of helmets would be thrown into doubt and his mom might let him bike without head gear.

The Schwegler School student’s hypothesis was the only thing that shattered. His study showed eggs are well-protected by the bike-helmet padding.

“I will wear it,” said Kirk, while depositing an exhibit poster of his work with other fair entries at the Douglas County 4-H Fairgrounds.

Jeanne Hetherington, a fair volunteer and former school teacher, said the range of inquiry shown in this year’s science fair was astounding.

There are more than 500 contestants, and winners will be announced later this week.

“Some are so clever,” Hetherington said. “It’s great … because children learn how to attack and solve problems.”

Kalen Wright and Madison Dennis, fourth-graders at Eudora West School, shed some light on the best approach to growing radishes.

The budding agronomy researchers monitored progress of radish plants for 16 days. Each radish seed was allowed to germinate in an old drinking glass with a variety of soil types. The students even explored the ability of a radish to grow in near darkness.

“We learned if you do it in small glasses, it stunts their growth,” Wright said. “We were surprised the one in the dark closet was the tallest. It was looking for light.”

Other students pushing the envelope of scientific endeavor:

Anastasia Slough, a first-grader at Sunflower School, studied how caffeine influences plant growth. Plants given a regular dose of caffeine-laced water “did not do as well” and had “black spots.”

Schwegler first-grader Anna Spring determined how many licks were required to reach the center of a Tootsie Pop. It turns out adults are twice as efficient as children. Grownups in the study needed 149 licks, while kids required 340 licks. She chronicled the number of people overwhelmed by the desire to bite the candy: 37 percent.

Wright said she learned a lot while working on the radish project. Her advice to future contestants: Plan well before starting a project and keep excellent records.

“It’s about what you learn,” Wright said, “not about whether you win.”