PAWNEE, Oklahoma - A simple challenge has kindness spreading through the halls of a Green Country elementary school.

Whether in science class, or archery, Pawnee Elementary students are thinking kind.

“People are doing, like, the little things and making people smile,” said fifth-grader Luke Mitchell.

Encouraging notes, nice words, and small gestures are catching on and making a difference.

“They've been holding open the door for me,” fourth grader Finlee Dvorak said.

"Yes, a big difference,” said Mitchell.

It all started during an assembly with motivational speaker and "Think Kindness" founder, Brian Williams. He challenged the students to change the world with kindness.

“At the lunch table one day, there was a girl sitting by herself, so I went and sat by her. And it put a smile on her face,” Dvorak said.

And they've found when someone is nice to them, the kindness is contagious.

“Then I'll go up to somebody else and make them feel good and then it just keeps spreading,” said fifth-grader Unique Stewart.

The students have logged 2,200 acts of kindness already this month.

Mrs. Coffey's fourth-grade class performed the most and won a surprise cupcake party for their good deeds.

But for many students, the challenge wasn't about winning.

“It just matters if we're being kind to other people,” fifth-grader Jayda Cook said.

Now the goal now is to keep it up the kindness to show what kids can do by simply being nice.

“Like, they can change the world,” fifth-grader Caitlyn Hawkins said. “They can make the world a better place for some other people.”