A young girl suddenly stops and listens as the sound of a trombone carries along the corridor at St Teresa's Primary School, Dumfries. "Where's that music coming from?" she asks.
The surprising answer is from another school 60 miles away in the same education authority, Dumfries and Galloway, which has 125 schools spread around 3,000 square miles of beautiful but sparsely populated southern Scotland.
A music instructor employed to visit these schools and teach children to play would spend more time with his hands on a wheel than his lips on a mouthpiece. So Dumfries and Galloway has devised a project that uses modern technology to shrink the distances.
With a trombone in his hands and a laptop at his side, Grant Golding sits in St Teresa's school library conducting a lesson with a small group of Whithorn Primary School pupils on a large flat screen in front of him.
"Right guys, I want D-C-D, which sounds like this," he says, and puts the trombone, an instrument with a huge physical presence, to his lips to play three deeply sonorous notes.
"Now you... one, two, three, four." A rasping assortment of sounds fills the room and Grant says: "Not too bad. Listen trumpets, you need to be ready with one and three already pressed down, so you're not like this," he waggles his fingers frantically, and the children on screen chuckle.
"Shane, could you shift your music stand a bit? That's fine. Catherine, that sounds really nice, so you can smile. Good. I think you've got a sticky button so let me show you what you can do later."
Grant reaches for a trumpet with one hand and a remote control with the other, and the small on-screen image of himself, which shows what the pupils are seeing, zooms in on his instrument.
"If you look at the bottom of your trumpet, at the valve, there's a tiny hole here," he says. "Turn yours upside down and have a look. That's it.
Now I want you to put a little squirt of oil in there, then wiggle your button up and down and twist your trumpet around, like this.
"What you need to do, Matthew, is raid your mum's bathroom cabinet. You can pay pound;30 for special creams for your trombone, but Nivea hand-cream works just as well." Grant lifts his trombone and detaches the slide.
"Put a wee bit of hand-cream in there - see?" Sixty miles away, Matthew nods his head. "Then put your slide back on, and give it a skoosh up and down. Right now guys, let's see if we can get this tune sorted."
The lesson continues, and the pupils are sent away with exercises to practise for their next session in a week's time.
"You can get a rapport with kids over the video-link," Grant says, as he waits for the next group. "But it's harder than face-to-face. So at the start I went around the schools and talked to them all, which let them see I was a real person. That makes it much easier for me now.
"The other thing I've noticed is that with the kids focused on the screen, a lesson goes more quickly. I can do a normal half-hour's work in 20 minutes. You need to be well-prepared, but I've found the technology quite easy to learn."
Teaching by video-link, which Grant has been doing since December, has had a marked effect on his normal teaching. He says: "I would always walk around during a lesson, but here I'm forced to sit in one place. I think that's better, less distracting."
As the tutor turns away to welcome the next session's remote learners, Alan Cameron, head of instrumental music teaching in Dumfries and Galloway, explains the project's background: "In principle we provide instrument tuition to any pupil who asks for it, from Primary 6 to Secondary 6 (Years 6-13). In practice, as one of the largest authorities in Scotland, we can't send an instructor to every small rural primary school.
"Instead we hold lessons in our secondary schools, and primary pupils have to be transported there, usually by parents. That can easily mean a round trip of 30 miles and it puts those pupils at a big disadvantage."
A proposal to the Scottish Executive's Future Learning and Teaching programme, which funds projects that "challenge the current concepts of schools and explore new ways of learning and teaching", led to the installation of video-link units in St Teresa's and four rural primaries: Drummore, Glentrool, Port William and Whithorn.
"There was an aspect of stepping out into the unknown," says Alan. "But we realised two things were critical to minimising the risk: the quality of sound and images, and the ability of the teacher.
"We deliberately didn't specify a particular type of instrument, but went instead for the best applicant - even though strings, for instance, would have been trickier to teach remotely because of the tuning involved.
"As you can see, Grant holds the pupils' attention so their teacher doesn't need to be constantly in the room, and he makes handling the technology look easy."
The running costs of the project are currently high, as ISDN6 has had to be installed in each participating school to deliver the bandwidth needed.
Costs will fall to zero, however, when Dumfries and Galloway connects its schools, as all Scottish education authorities should in the near future, to the national broadband network known as SSDN.
At Whithorn Primary School in the afternoon, Grant looks a little smaller on the 42-inch screen than in real life, but his personality still holds the pupils' attention. Valuable aspects of the system which are more obvious at this end include remote control of the Whithorn camera from Dumfries and split-screen viewing, with the teacher in one half and his laptop screen in the other, allowing pupils to follow - and the teacher to refer to - the musical notation.
"We're just scratching the surface with all this," says headteacher Norman Hughes. "The quality is very good. Now we've seen how easy it is to use and how well the kids take to it, I'm really excited about the possibilities for teaching and linking up with other schools."
Requirements for a school video-link system:
* Polycom VSX7400 IP ready system, with 512 ISDN module, dual monitor adapter, and people and content module.
* Samsung 42 inch PMA225EZ plasma display.
* Mobile stand or wall-mounting kit with shelves. ISDN6
* Delivery, installation and commissioning (all five units): Pounds 39,075.
* BT line rental: pound;7,200 per annum