“COSI is at the top in serving its community and using science very effectively in delivering its message.”

When the reborn Memorial Hall opened as the Center for Science and Industry in 1964, a Columbus advertising executive’s dream had come to pass at last.

Sandy Hallock’s idea, inspired by a visit to the Museum of Science and Industry in Chicago, took six years to pull off. It required the help of area business leaders and the Franklin County Historical Society, as well as $502,000 in county funding to renovate the hall in downtown Columbus.

Five decades and one significant move later, the nonprofit center is viewed as a standout among its peers.

“COSI is one of our leading institutions, and not just in the United States,” said Anthony Rock, president and CEO of the Association of Science-Technology Centers, a nonprofit organization encompassing nearly 600 centers and museums in more than 40 countries.

“COSI is at the top in serving its community and using science very effectively in delivering its message.”

The center moved in late 1999 to the former site of Central High School, less than a mile from its original home, which is now county offices. And it’s getting a head start on celebrating its March 29 milestone, with the opening this past week of an exhibit called “50 Years of COSI.”

Much of COSI’s success thus far is rooted in its ability to make science and industry accessible, engaging and entertaining.

“COSI is in the top tier of science centers nationwide in terms of creativity, content, education, inspiration and the spirit and talent that the team brings to every guest every day,” said Kathryn Sullivan, a former astronaut who brought “star power” to COSI as its leader from 1996 to 2006.

“The core of its DNA is solid science — based on solid educational research and design — in a wrapper that seems to just be fun.”

Using a range of exhibits, the center has worked throughout its history to make science education cool.

For example, visitors to the old site might recall the original Foucault Pendulum, modeled after an 1851 experiment by the French scientist Jean Foucault proving that Earth rotates.

Or maybe the simulated Coal Mine, with its inky black walls and real mining equipment, rings a bell.

At the current location, the traveling exhibit “Titanic” drew a record 226,000 visitors during its six-month run in 2005. Five years later, it returned.

“Science centers like COSI are special places for opening the imagination of kids and adults to the scientific laws that make our universe work,” said John Beacom, an Ohio State University professor of physics and astronomy, whose teenage daughter has visited the center since she was 3.

Younger people are drawn to the hands-on atmosphere, with 300-plus interactive options spread throughout themed areas such as Gadgets, Life, Progress and Space.

“COSI does a very good job of taking something abstract and simplifying it down, or taking something very simple from the household and using that to explain a high-level concept,” said David Greer, an information-technology manager and a COSI volunteer, who visited the center while in high school and returned often with his daughter, Jessica.

Those frequent visits influenced 18-year-old Jessica Greer, now a freshman pursuing chemical engineering at the Massachusetts Institute of Technology in Cambridge.

“COSI showed me that discovering things is really fun and that it’s OK to be super-nerdy and study engineering,” she said.

But balancing entertainment and education isn’t necessarily easy.

“That’s a valid tension in the field,” said David Chesebrough, president and CEO of the center since 2006. “We have to make sure that what we bring in meets our mission and fulfills our business model.

“If we have to sacrifice one (goal) for the other, we focus on education.”

From the start, COSI has strived to be an innovator.

In 1972, the center pioneered overnight “camps-ins” focused on science and technology — a program later widely adopted by science centers nationwide.

“The science was fun, and the experience probably helped shape my thinking,” said Grandview Heights resident Aimee Kennedy, who at 10 attended a camp-in with her Brownie troop.

Like Jessica Greer, the 37-year-old Kennedy credits COSI with helping to guide her career path: Today, she is vice president of education and STEM learning at the research-centric Battelle, a nonprofit organization in Columbus and longtime financial supporter of COSI.

“COSI helps students at very young ages understand that they have the capability to be a scientist,” she said.

The center’s first 50 years weren’t without setbacks, however.

The most difficult period began after the move from the 116,000-square-foot Memorial Hall site to the 320,000-square-foot building incorporating much of the former Central High, on the west bank of the Scioto River.

The $125 million site was funded jointly by the city of Columbus, the state and private donors, and logistically, the significant expansion presented challenges.

Preparing for the move, Sullivan recalled, was akin to making a Thanksgiving dinner “with all the plates, hot and cold, coming out at the same time.”

The aftermath proved turbulent in surprising ways.

Although a record 1 million people visited the center in 2000, the first full year on the riverfront, public curiosity soon dissipated. Visitors talked of missing both the bustling intimacy of the old venue and some exhibits that weren’t retained.

“The (old) location was kind of worn and straining at the seams because of audience growth,” recalled Sullivan, now an acting undersecretary of commerce in the Obama administration.

“But guests felt the clean and spare line of the new architecture was a little too barren, and they liked the friendly clutter of the old place.”

The public dissatisfaction took a toll on COSI attendance.

Fewer bodies in the center meant less earned income, a serious problem for a center historically funded largely through general admissions, memberships, traveling-exhibit surcharges, workshops and such.

What’s more, the much-larger facility cost more to heat, staff and fill than the original site.

With the financial challenges persisting, center administrators turned in 2004 to the county for help.

The proposed solution was a property-tax levy that would raise $12.4 million yearly to fund the center.

When Franklin County voters overwhelmingly rejected the ballot measure, however, COSI was left to slash its already-shrinking budget — to about $11 million a year, down from a peak of $20 million at the time of the move.

The center laid off 67 employees, shuttered its southern wing, closed the Planetarium and three other exhibits, and curbed its hours from seven days a week to five.

Even with the cost-cutting, the center ended fiscal year 2004-05 with a $1.7 million deficit. It also recorded a post-move attendance low of 482,088.

COSI found its way back into the black during the next fiscal year, but the situation remained fragile.

“It was like a roller coaster that forced us through the stomach-turning dip down,” Chesebrough said. “We had to figure out how to get it back rising.”

Major corporate and individual donors helped keep the center afloat as attendance stabilized. COSI officials, meanwhile, continued working to recapture some of the lost intimacy, making the long center hallways feel warmer and its vast space less sparse.

“We look and feel very different when you walk in today than we did when we first moved here,” Chesebrough noted. “You feel a vibrancy — there’s color, engagement, (science) carts, electronic signage.”

The most-effective solution to the venue’s challenges involved another innovative idea: science and industry partnerships, with COSI integrating into its exhibits and sights the daily activities of scientists and others in industrial and technical fields.

When COSI hosted the annual conference of the Association of Science-Technology Centers in 2012, the partnerships, which have helped boost the bottom line, were the talk of the gathering.

“There’s a saying in our field that COSI demonstrated how to turn a science center into a center for science — by forming relationships in the science community,” said Rock, the association’s CEO.

For 2012-13, COSI reported a balanced budget of $17 million, with 75 percent of that covered by earned income.

Attendance also is recovering: Roughly 658,000 people visited in 2012-13, up from 627,800 the previous fiscal year.

The financial stability has allowed COSI administrators to focus on matters that have made the venue popular.

“Real science, real objects, real stories and one-of-a-kind partnerships have put us back on the scene as a national and international leader,” Chesebrough said.