Mikey Krause had waited practically his whole life for this.

The 3-year-old can recite every line spoken by Toy Story character Woody and he reenacts the movie with his toys. Now, wearing a yellow Woody T-shirt and a brown fabric holster on one hip, he stood awestruck, face-to-face with a Buzz Lightyear, several times taller than him at a Franklin Institute exhibit.

But he couldn't stand still for long.

"Come on!" he yelled, running between Buzz and the characters Mike and Sulley from Monsters Inc.

His aunt, Jen Krause, 22, tried to keep up, pushing his stroller and carrying his cowboy hat and plush Woody doll. This was the most excited he had been all day, said Krause, of Bridesburg.

"Whoa!" he said, as he watched a spinning model of the space ranger character on a screen nearby.

"This kid does not do anything but watch Pixar movies," said Sara Hite, 33, Krause's girlfriend.

So they had to bring him to the interactive exhibition The Science Behind Pixar on Saturday, opening day. Krause became a member of the museum because of this exhibit, which ends Sept. 5. She wanted her nephew to learn more about the films he loves.

The 14,000-square-foot exhibit, on the first leg of a national tour, shows visitors what goes into making Pixar's popular films through a focus on science, technology, engineering, and mathematics.

Larry Dubinski, president and CEO of the Franklin Institute, said he hopes visitors see how they can use those school subjects for exciting careers. This could be the most popular exhibit the museum has ever had, he said, and it drew large, but manageable, throngs on Saturday.

Philemon Hightower, 6, of Chester County, was among the children hopping from display to display Saturday, learning about computer models used in Cars, programs that control the movement of schools of fish in Finding Nemo, and the effects of manipulating angles of light in a miniature set from a scene from Up.

"There's more!" Philemon said, pulling his mother, Delilah, to a robot building station in a WALL-E exhibit.

The exhibition brought out fans of all ages.

Ivy Liu, 24, and her boyfriend Chris Liu, 23, came from Manhattan. Ivy said she watches a lot of Pixar movies and thinks the characters are cute. They said they never realized how much mathematics and science are involved in creating the movies.

Allyse Andrews, 17, a senior at Central High School, felt inspired. She is a mentor in the Franklin Institute's youth leadership program Partnerships for Achieving Careers in Technology and Science and wants to share what she learned with her middle-school mentees. Andrews plans to study criminology in college and work in forensics.

She felt nostalgic as she walked through displays of characters from Toy Story and The Incredibles.

"Reliving my childhood experience, basically," she said.

610-313-8207 @MichaelleBond