From the intimate to the ordinary, life in this Midwestern college town is changing. The iconic Hamburg Inn, the diner where presidential candidates have stumped for decades, still dishes up its famous "pie shakes." But take a closer look:

Bubble tea shops outnumber Starbucks 3 to 1, and nearly 1 in 10 students at the University of Iowa hails from China.

Iowa City has gone global.

Stroll to the Old Capitol Mall on any given day and you'll see a lunchtime crowd from faraway cities like Beijing, Shanghai, Dalian, Shenzhen and Wuhan. Take note of the cars that pass you. Mixed in with the souped-up Ford F-250s and Dodge Ram pickups preferred by natives are Maseratis, BMWs, Audis and Mercedes-Benzes. You might even glimpse a Lamborghini or a Ferrari.

Chinese students pay an estimated $70 million a year in tuition to the University of Iowa and pump an estimated $100 million into the local economy. They've become such a financial boon they help subsidize the education of their American peers.

The dramatic rise in Chinese students -- from a few hundred in 2000 to more than 2,500 today -- has brought culture shock and a series of major challenges.

A lack of dorm space resulted in hundreds of students, most of them from China, being warehoused eight at a time on beds in dorm lobby areas for weeks, even months. Segregation within the classroom became common. Many Chinese students struggled to speak English and cope with the demands of English-based curriculum. Professors grumbled about how to teach in that environment.

These issues still reverberate across campus.

A mandatory program last fall meant to help international students better understand American culture failed miserably.

"The international students hated it," says Ron McMullen, a visiting associate professor of political science and former U.S. ambassador to Eritrea.

The class was canceled. The lesson learned: The university can be better about engaging international students, but it works both ways. "The international students could be better about engaging," says McMullen, who helped organize the class. "That's a tough one to overcome."

Solving these issues and better integrating students has become a priority. A university panel last year spent months examining the academic and social environment for international students. In November 2014, the committee said three gaps must be addressed for the long-term health of the university: cultural differences, institutional processes and language barriers.

"International students sometimes arrive on campus unsure of where they will live, on or off campus, or even where, exactly, the university is located in the United States," the International Student Climate Subcommittee said.

Change has begun. New dorms are being built to meet student demand, menus are being changed at cafeterias to accommodate the growing international population, and the school now hosts welcoming parties within China for new students. Students also are greeted at the airport when they touch down in Iowa.

The university, McMullen says, is aiming to help international students "assimilate, acculturate and get a fuller, richer college experience."

It's also asking: "How do we get American students, especially Iowans who can be noncosmopolitan, to know more about the world?"

'A very tense situation'

The growing pains playing out in Iowa City are happening in college towns around the nation, from Tuscaloosa, Alabama, to Corvallis, Oregon, to Lincoln, Nebraska.

Twenty years ago, about 42,500 students from China attended college in America, most of them for post-graduate work. Last year, that number reached nearly 275,000, with most coming for undergraduate degrees. Chinese students make up 30% of all international students studying in America; the other most-sought international students come from India, South Korea and Saudi Arabia.

The rise of Chinese students is most pronounced in the Midwest, with Big Ten universities heavily recruiting students within China over the last decade. Among the top 20 American universities with the highest Chinese student populations, nine are from the Big Ten, according to The Brookings Institution.

The University of Illinois at Urbana-Champaign leads the way with 10,000 international students, including about 4,900 from China. Purdue is not far behind with 9,000 international students, including 4,600 Chinese. At both universities, international students make up nearly one-quarter of the entire student body.

Michigan State has the highest population of Chinese students in the nation, with more than 5,300. Ohio State, Indiana, Minnesota and Michigan have seen an explosion in their Chinese student bodies: Each school has more than 3,000 Chinese students.

At Iowa, the number of Chinese students outnumbers the combined African-American and Latino student population.

The influx of Chinese students began about eight years ago, the result of America's great recession and China's burgeoning middle class. American universities were in crisis mode with their budgets getting slashed. Administrators needed a viable financial alternative.

"Those are the two forces that are bringing about this huge growth of foreign students into the United States," says Neil G. Ruiz, a senior policy analyst and associate fellow for the Brookings Institution. "The impact is great. It helps the universities in the short run get the tuition and the students they need in terms of revenue."

The long-term implications, Ruiz argues, are even greater. "Foreign students in Iowa City are connected to these cities abroad like Beijing, Shanghai, Chengdu, Wuhan. They are bridging two economies simultaneously ... and that's an asset in the global economy."

Top university officials began jetting to Beijing. They found parents eager to send their children to America to earn a degree -- and able to pay cash for out-of-state tuition, often triple the price of in-state.

"State funding is going out the door," says Sarah Gardial, dean of the Iowa business school. "The funding model actually encourages us to take a higher percentage (of international students). That's why we started down that path."

The dramatic rise in international students has stirred concerns, from state lawmakers who believe their in-state population is being replaced by foreign students to faculty who believe administrators are selling out the value of a degree for a quick-fix financial solution.

"It's creating a very tense situation across all the different levels of the institutions," says Chris R. Glass, an assistant professor at Old Dominion University who has examined the social and academic experiences of international students across America.

"You're seeing faculty who think the burden has been placed on them. ... It's happening everywhere, and faculty are mad."

The caliber of students has come under scrutiny because of the cottage industry of educational placement agencies that has popped up in China. Reports of widespread abuses among agencies are rampant, from forging college essays to changing test scores.

The students also are arriving at a time when Americans have become more and more skeptical of China's motivations, creating tensions on college campuses.

Chinese students have had their cars spray painted with messages to go away. Many can tell a tale of being harassed. Or of not fitting in, either by choice or because they didn't feel welcome.

CNN spoke with dozens of Chinese students at Iowa in February. Nearly every single one said an American has at least once yelled at them "Go back to Asia!"

They spoke of feelings of isolation and their desire to fit in.

A case study in micro-aggression

Yuhao Chen has experienced that feeling of isolation. All she knew of Iowa before she arrived was that it was a farm state in the middle of America "where people just eat corn."

With its population of more than 70,000, Iowa City is hardly a small town to most Americans. But it was a shocking change for Yuhao, who comes from a city of 10 million. She missed the familiarity of home. Her self-esteem plummeted; she feared she would jumble her words when she spoke English.

It's a common experience, she says. The language barrier causes students to withdraw.

They don't want to embarrass themselves and so they stay in their comfort zone. They flock to other Chinese students. Many might already be naturally shy, she says, "and when they come to a completely new place, the difficulties can be even more pronounced."

Yuhao, a senior majoring in psychology, decided to take action. Two years ago, she and a friend formed a student organization called Heart Workshop to help international students with their mental health and well-being.

She had seen a friend her freshman year become so stressed out by the change in environment that "she didn't want to go out of her room."

"That's one of the things that really touched me and kind of drives me to find out what other difficulties there are and why students -- especially international students -- don't want to seek out mental health services."

In summer 2013, she and her friend began surveying juniors and seniors from China. They asked probing questions: Do you feel comfortable socializing with Americans? What kind of difficulties have you had living and learning in the United States? What percentage of your friends are American?

She was fascinated by the responses. Most had very few American friends, but nearly every respondent said they hoped to remain in the United States for work after graduation despite their social struggles. Visa restrictions, however, often prevent that.

Through Heart Workshop, she was able to make breakthroughs among a Chinese population often resistant to mental health services. Gradually, people began opening up.

An incident that happened around that time still brings a lot of pain to Chinese students. A Twitter account called UIasianprobz began posting photographs of Asian students asleep in the library or driving fancy cars. Hateful and negative remarks were posted and shared.

Chinese students who spoke with CNN were on the verge of tears whenever the Twitter account was mentioned. They felt unwanted and unappreciated, not just by the American students but by top university officials who remained silent.

For Yuhao, it was a case study of micro-aggression, a glimpse into something deeper going on around town.

But, she says, something positive emerged. The incident mobilized international students to stand up for themselves and push university officials to do more to integrate campus life -- to tell administrators that "international students really deserve to be accepted on campus."

Bringing students together

Even before the Twitter incident, the business school began deep introspection, pondering what could be done to get students to "appreciate and work with someone who's not like you," says Gardial, the business school dean.

One in 5 students at Iowa's Tippie College of Business call China home -- much higher than the rest of campus.

The business school put every professor through a course on how to pronounce Chinese names correctly. "We said, 'Hey, job one is to show respect by getting someone's name right,'" Gardial says.

The school then began teaching professors how to incorporate diversity into the classroom. Programs were formed to bring students together. Slowly, inroads were made: Students have begun eating together and interacting in the halls.

Ben Cunningham and Qiqi Shi are business students who forged a friendship through the international buddy program.

In October, American and international students carved pumpkins in the business school. "Something you don't see a lot in a college of business," Gardial says with a laugh.

She admits the business school struggles with verifying the academic chops of every international student "in terms of their academic background, their language skills -- that kind of thing. But I would say that we're getting better and better."

It's incumbent on the university, she believes, to help the students "overcome that barrier and to give them the kind of supportive resources that they're going to need."

International students must pass mandated courses in English as a second language. The business school has established a communications center to help with speech and writing skills.

Gardial also meets with business leaders across the state to find ways the international students can stay in the States longer. "We are seeing companies without question look at ways that they can keep students here as much as possible," Gardial says.

"How we deal with our international students is very much a part of that larger question," Gardial says, "which is: How do we make sure our students are prepared?"

"We see this as an enormous opportunity that we've got that kind of diversity," she says. "But here's what we have found out: If left to their own devices, the students don't naturally integrate in the way that they should."

Relationships must be forged.

Qiqi Shi and Ben Cunningham, two business school students, dine on hot pots at the Szechuan House, a Chinese-owned restaurant that serves traditional food. The two laugh and share tales like most college kids.

Qiqi is a junior majoring in finance. She is from Macau, one of two special administrative regions of China, with a population of more than 600,000. Ben is a junior majoring in business analytics. He is from the small Iowa town of Grinnell, population 9,000.

The two are part of an international buddy program in the business school that pairs American students with those from overseas. More than 120 students participated this spring.

Ben and Qiqi signed up for the program a second time because they found it invaluable. "It's a cool way on a small scale to bring people together who would otherwise not meet," Ben says.

Adds Qiqi: "It allows us a cultural exchange with the American students."

They say they just wish the rest of the student body was more open to change and diversity.

Too many American students, Ben says, "think it is funny or amusing in an ill-spirited way" to make fun of the Chinese students.

"International students, we're not any different than Americans," Qiqi adds. "We're just from a different place, with a different language. But we are willing to talk and communicate and share our culture, and we're willing to learn new stuff."

The question remains: How many will join them?