Alan Alda is asking a question of scientists and although, on the surface, it seems easy enough, he is asking them to answer in such a way that an 11-year-old can comprehend the answer.

The question? “What is sleep?”

The M*A*S*H actor, who is a visiting professor in the school of journalism at Stony Brook University, in New York, has posed the question to scientists around the world, warning them to keep it simple because the judges of the entries with be 11-year-old children.

“I think that 11-year-old kids are probably all reaching that point in their lives when they want answers to complicated questions, but they want them with clarity,” said the West Wing alum. “They don’t want to be talked down to. It’s a very interesting time.”

Alan Alda challenges scientists to explain sleep to an 11-year-old http://t.co/CegvigFV83 pic.twitter.com/HzwWVIZXuW

— NBC News (@NBCNews) December 2, 2014

The “Flame Challenge” is celebrating it’s fourth year and is organized by the Alan Alda Center for Communicating Science, at Stony Brook University. Each year, the challenge poses a question to researchers. The challenge got its name from the first question posed back in 2011: “What is a flame?” Alda said he started the contest because of a lame answer he received to the flame question from a science teacher years ago.

“In a way, it was a lucky accident,” Alda told Live Science. “I wondered what a flame was when I was 11, and I asked a teacher to explain it to me. All she said was, ‘It’s oxidation.’ I never got a good explanation. I didn’t know what oxidation was. Oxidation was just another word for me.”

Actor Alan Alda gives a peculiar challenge to scientists: http://t.co/6vqv9DwAXr pic.twitter.com/jWRdYFbqqt

— AOL.com (@AOL) December 2, 2014

Alda’s question in 2012 asked scientists to describe time, while the question the following year asked researchers to clarify the concept of color.

Nearly 27,000 students are called on to judge the entries.

Anyone in the science arena can submit their answer to The Flame Challenge by writing an explanation, filming a video or creating a graphic. The deadline for entry is Feb. 13, 2015.

Can you explain sleep to a 6th grader? http://t.co/ffZxEgHk4W ᔥ@EdWeekTeacher pic.twitter.com/yBwkCWx6CJ

— Education Week (@educationweek) December 3, 2014

After a screening process, two winners, one for a written explanation and the other for a video or graphic entry, will each be awarded a $1,000 cash prize, flown to New York City to meet Alda and be honored at the World Science Festival in May 2015.

“I really do hope that scientists from all different kinds of fields will give it a try,” Alda said. “Somebody said once, ‘How do I know what will be appealing to an 11-year-old?’ We said, ‘Why don’t you talk to one?’ Because that’s the essence of communicating. Keeping in mind who you’re talking to.”