Art teacher Julia Mooney has no trouble these days figuring out what to wear to work: a gray button-down dress.

She has been donning the same dress since the school year began to teach her students at William Allen Middle school in Moorestown a lesson about eco-sustainability, image,  and social acceptance. She plans to keep it up for 100 straight days. Her last day will likely be in February.

"I like wearing my dress every day," Mooney, 34, said in a recent interview after school in her art room.  "I'm starting to feel like this is what I wear to work."

Known as one outfit, 100 days,  her campaign has caught attention around the country and some teachers in her South Jersey school district, including her husband, Patrick, a high school history teacher, are joining in. So far, one student, Sofia Rubich, a second grader, who read about it during a current-events lesson with her mother, has joined, too.

"At first I probably thought she was crazy," laughed Patrick Mooney, 38, who is wearing the same khaki pants and dark blue shirt for 100 days. "Then I thought there was no good reason not to."

His wife, a teacher for 10 years, wants her students to become more aware of how much they consume, often due to peer pressure to buy the latest fashions, and find ways to reduce their environmental impact. She also wants them to learn a cultural connection between art and social activism.

She doesn't use class time to talk about her project, although her seventh- and eighth-grade students have noticed her attire. A sign on the classroom door reads: "Creativity takes courage." She uses an Instagram account "oneoutfit100days" to document the project where students and others can learn about her sustainability message.

She recently asked her students to write their thoughts about the project on lime-green note cards. Her message seems to have struck a chord in the community of 20,000 where the median household income, according to the Census Bureau, is about $126,000.

"Mrs. Mooney is a real game-changer because she is showing so many people it doesn't matter what you wear or cool you look," wrote Emily Thornton, 12, a seventh-grader. "There are bigger problems in the world like pollution."

Said eighth-grader Cathy Romano, 13: "I love how inspiring it is to many people and getting us to see that we don't need lots and lots of clothes."

Elsewhere in the Burlington County district, Sofia, the second grader who is following Mooney's example, gets asked a lot of questions from her Baker Elementary classmates, but seems unfazed and explains why she is wearing the same dress, said her mother, Ana Cafengiu, a podiatrist. Sofia calls her outfit — a blue top with a gold sequined heart and attached skirt her "happy dress."

"It's very easy to get dressed in the morning," Sofia told Mooney in an e-mail message. "I'm having a lot of fun."

Cafengiu said the family supports the youngster in her attire, with only one concern — the thinly made dress, purchased on clearance, may not last for 100 days. Sofia packed the dress on a recent weekend trip but also wears other outfits on the weekend and after school, her mother said.

In her first post in September, Mooney wrote: "A challenge to be mindful of what, why, and how we consume. Let's use our energy to do good instead of looking good." She posts almost daily, with a countdown to February and often sharing alarming statistics about clothing consumption. She has picked up more than 1,300 followers and a few have posted messages that they also plan to do the same thing.

The response from teachers and students has been positive, Mooney said. The most frequently asked question she gets about her outfit is: "Do you wash it?' Mooney wears an apron to protect her garment from stains and occasionally adds a colorful scarf or cardigan to slightly change her look. She wears other clothes on the weekend.

Yes, she does wash it, usually by hand, but Mooney has a spare identical dress, purchased for about $50 from "Thought Clothing." She selected the dress, made from hemp, a durable fabric, partly because the London-based company encourages customers to wear garments more than once before washing, repair rather than replace items, and give away unneeded clothing.

Mooney and her husband also practice sustainability at their Audubon home with their three children. The family raises chickens in their backyard (the kids take the compost out) and grows vegetables. Julia makes the kids' clothes or buys second-hand items at consignment stores. Patrick Mooney said the project became an eye-opener "when you realize you have 50 shirts you haven't worn."

Beth Glennon, a math teacher at Moorestown High for more than two decades, said she was inspired by Mooney's one outfit campaign. "I'm not surprised that she's doing this. This is completely her," said Glennon, 47. " She 's artistic in every way."

When her triplet sons went off to college this year, Glennon thought she would have an empty nest at her Haddonfield home, along with husband, Joe. She was shocked to find a closet packed with polo shirts her sons left behind. The couple also has an older son. She wears one of her sons' polo shirts to school. Her oldest son, Richard, joked that she was "holding on to the last fiber of them."

"For me, it's a fun way to keep the boys on my mind instead of missing them every day," said Glennon. "Plus, I'm forced to clean out their closet."

Kelly Gartland, who teaches AP ceramic and sculpture at the high school, is wearing the same dress, a blue denim dress. In upcoming lessons, she plans to use the project to discuss how artists help shape public dialogue and how students can identify priorities in their personal lives.

Gartland, 33, said she donated five bags of clothing and has no plans to resume her old shopping habits when the project ends. If the dress lasts, she may wear it until the end of the school year, she said.

"Even when this is done I'm not going to be replacing as much," Gartland said. "It seemed like an easy way to simplify my life."