Susan Mansfield covered her gray hair with a floppy, baby blue hat, grabbed some books and walked out the doors of her government-subsidized housing toward the bus stop.

It would take the 88-year-old more than an hour to get from Hixson onto the UTC campus, where she would make her way to class and study alongside teens young enough to be her great-grandchildren.

“I start my sixth year of auditing class at UTC in this next term,” said Ms. Mansfield proudly. “The students know me as the little lady who wears the hats. They love me.”

Ms. Mansfield is among a handful of senior citizens spicing up classrooms on the University of Tennessee at Chattanooga campus. Since the mid-1970s seniors have been allowed to attend classes for free, and many use the opportunity to keep their minds fresh.

“My doctor tells me to walk and stay in school,” Ms. Mansfield said.

The school offers free classes to seniors in compliance with a state law that makes auditing free for people over 65, university spokesman Chuck Cantrell said. The seniors don’t take tests or earn college credit but are able to expand their understanding of subjects they are interested in.

He said students and professors enjoy their participation in classes. Liberal arts classes especially come alive when seniors can add their experiences, whether during World War II or the Great Depression, to the class discussion, Mr. Cantrell said.

“Imagine if you are taking an economic, history or literature class and the richness in the discussion that can come from students from different generations and different life experiences,” he said. “We believe there is a real benefit to our students.”

William Moon, 84, has audited classes at UTC for 15 years with his wife. Throughout the years, he has taken ancient history three times from a professor he says “teaches beautifully.”

The former lawyer, who attended the University of Chattanooga and Vanderbilt University, said his favorite subjects are geography and Southern history.

“I didn’t get the education I wished I had, and I was anxious to get back to school if I could,” he said. “Boy, there are some good teachers out there.”

As they strive to stay sharp, senior auditors have had an eye on change at UTC. Over the years, Mr. Moon said, he has watched the campus transition from being a conservative and religious atmosphere to one more liberal and secular.

“Some of the students talk like raving socialists,” he said, laughing. “Most kids are looking around for new thoughts. ... They use words that you certainly aren’t going to hear in any Sunday school. It is different, that’s all.”

Ms. Mansfield said she sees many students struggling to engage in their education.

“I am a live wire, and I am amazed at how students are eating or snoozing (during class),” she said. “I am always thinking, how are you going to pass this, but they do.”

Dr. Craig Laing, an associate professor of geography at UTC, has had Ms. Mansfield in several of his classes. Most 18-year-olds haven’t traveled a lot, so they listen carefully when Ms. Mansfield shares about her excursions abroad, he said.

“She is conscious of not taking up class time, but sometimes it is worth it to just let her talk,” Dr. Laing said.