Ten-year-old Carmen Allen was fascinated by the fuzzy baby chick nestled in the palm of her hand.

"I like that one," the Wilson Elementary School fourth-grader said. "This is cool."

Carmen was one of dozens of an estimated 500 third- and fourth-graders in the Corvallis and Philomath school districts who will take part in the 10th annual Ag Expo that runs through Thursday at the Benton County Fairgrounds. Its aim is to teach young people about the link between agriculture and their food, clothing, toys and even medicine. The theme of the expo alternates every other year between agriculture and forestry, according to coordinator Dick Powell of Starker Forests. This year, it was agriculture's turn.

Carmen's fellow students pressed their noses close to the warm glass of an egg incubator. Grace Mountainspring of the poultry science club at Oregon State University informed them that it takes 21 days for chicken eggs to hatch; 28 days for duck eggs.

"Look!" a student exclaimed, "that one's moving!"

Mountainspring held up a tiny white chick and then a brown one and said that when the chicks mature into hens, one will produce white eggs; the other brown eggs, but nutritionally, the eggs will be the same.

Bill Young, OSU Extension Service, and his wife, Carol, provided facts about the crop for which the Willamette Valley is famous: grass seed. They invited the students to guess how many seeds it took to make up a pound of grass seed. Turns out, the answer depends on the variety of grass seed: It takes 450,000 seeds to make up a pound of orchard grass but bentgrass seed is so small, it takes 6 million seeds to weigh a pound.

OSU instructor Mike Gamroth encouraged his group of students to smell several types of cattle feed, including whole cotton seed, ground corn, grass silage, corn silage and alfalfa hay.

"It's cool," Bradly Landucci, 10, said. "Cows eat a whole bunch of stuff, not just grass. I thought they just ate grass before."

At the Oregon Agriculture in the Classroom station, Darcy Kirk, who lives on a hazelnut farm near Independence, helped youngsters make living necklaces: A pinto bean is placed inside a wet cotton ball for a few days, and the bean sprouts roots, ready for planting.

At the nine education stations, students learned about the many types of ag products grown or raised in Oregon, ranging from seafood on the Oregon coast to wheat and barley in the state's eastern dry lands.

Mark Keller, of Oregon State University, told the youngsters that one cow hide produces enough leather to make 144 baseballs, 20 footballs, 18 soccer balls or 12 basketballs.

The Ag Expo will continue through Thursday, with a morning and afternoon session each day.

Alex Paul can be contacted at alex.paul@lee.net or by calling 758-9526.