Lorna Clarkson, music director for Kinderling, an online and digital radio station (kinderling.com.au) aimed at the under-5s, was hired to fill 23 hours every day - the missing hour is given over to talkback, for parents, not the kids - and the brief was both very demanding and very simple.

Firstly the music had to be "a really safe and reliable companion for families", removing the need for parents to spend all their time with a finger hovering over the on/off button, ready to block offensive material.

After all, as Clarkson says, it's not just what the pre-schoolers hear but the fact that they'll "sing it back. And coming out of a child's mouth it sounds completely wrong and inappropriate".

Secondly, it had be "fun, playful [with] positive messages", particularly for girls, not so straightforward when, as R&B fan Clarkson points out, the most popular sound on radio these days may have "the beat, the energy [but] lyrically I don't think it speaks to and about women particularly positively".

Having cleared those hurdles though, the music could be anything good from anywhere and any time.

"I get to plumb the depths of music from across the ages and from across all musical styles," Clarkson says. "If I can't find enough in R&B I can go to classical or I go to indie rock or blues or jazz. I can pick from any musical styles I think will connect to kids, pick out those great tracks that have a good beat, have a good melody, have a good energy."

And energy, its presence and its absence, is the thing that drives the station.

"The way we program the music through the day it is all about energy," explains Clarkson. "When the kids are up and getting out of the house, the energy is super up; when we are trying to get them to sleep in the evening, then it goes right down and tries to calm everything when they might be going feral before bedtime."

So you might find across the day the White Stripes and an ambient album, Rhys Muldoon (whose Give Me The iPad is already one of the most played tracks on the station) and a well known classical composition, Justine Clarke and Burl Ives, or Sia and Patsy Biscoe.

"I knew I had a pretty broad universe to call on," says Clarkson, who doesn't have children but firstly drew on both her own childhood (the music her parents and grandparents played to her like Danny Kaye or The Sound Of Music), her interactions with the five god-children she babysits, and then research into music made for children around the world.

Isn't worrying about "appropriateness" and positive images being too fussy and do-right when most under-5s aren't paying that much attention to the words or the messages, let alone understanding the nuances? Will they block songs about princesses and look for ones about girls as scientists?

"Girls still love princess movies and songs about princesses, even though it's a gender stereotype, but what I think is exciting is when you find a piece of music that not only has lyrics that are a bit bolder but the music has been written really well, so you would want to hear that track even without the lyrics," Clarkson says, singling out a North American children's music product called Big Block SingSong and their track Princess, which is part hip hop, part rock "really good attitude in the musicality of the track" with a lyric about how she may be a princess who likes pretty dresses but she can also kill a dragon.

"I thought that is really cool, that is the message we want to send out to kids."

But yes, sometimes a song is there because it's just fun.

"I'm certainly not going to do a thesis on every song there," laughs Clarkson. "If it sounds like a great track and the lyrics aren't offensive and there's nothing obvious in there, then it will be on the playlist.

"I think it's really nice to tap into our own sense of being a child. It's nice to be reminded of when the world was an amazing place to be discovered and everything was new and everything was possible."