Michael Rosen bounces on the sidelines like a boxer before a title fight, tapping a handrail and stretching out his arms. The one-time children's laureate might well be nervous - he's about to perform poetry to a bigger crowd than squeezed into Wembley for Live Aid.
But the audience of 90,000 is in hundreds of small pockets across Scotland, and some beyond - about 1,300 schools, in fact, 1,000 through the BBC Scotland Learning website and 300 through a BBC stream to Glow. A P5 class from Glasgow's Garscadden Primary is right before him in BBC Scotland's HQ, but every other child watches online.
This is the first of the Scottish Book Trust's Meet Our Authors live events, following a trial with Anthony Horowitz last year. The events allow huge numbers of pupils to hear and quiz some of the most famous children's novelists and poets.
Mr Rosen is an inspired choice to kick off: his approval of mildly anti- authoritarian behaviour marks out the 40-minute slot as very different from day-to-day lessons.
He muses on conventions of essay writing: what if you put "tomorrow" for the date, or write "Shona" at the top when your name is Dave? He revels in the thought of children annoying librarians by asking for his books, whose titles include You Tell Me and Wouldn't You Like to Know?
He shoots off at tangents, finding humour in details of everyday life (the transgressive pleasure of bending a toothbrush to breaking point) and surrealist flights of fancy (did anybody know broccoli came from large green men's armpits?)
He fields questions from around the country. Some ask what a poem is; he defines it as saying "interesting things in a small space".
The Garscadden pupils never take their eyes off him - and one girl keeps bursting into uncontrollable giggles at each of his many extravagant flourishes.
A five-hour drive away, at Lybster Primary in Caithness, pupils lose little from watching online, during a whole day based around reading. Afterwards, several pupils tell P4-7 teacher Andrew Martin it's been "the best activity day ever".
The screen freezes every few minutes, but Mr Martin turns this to his advantage: he asks the 42 pupils to guess what Mr Rosen will say next; on one occasion they are amused when the poet's expressive face freezes at a particularly eye-popping moment.
There is excitement, Mr Martin says, in watching live. Pupils know they must be ready by a certain time, which raises the anticipation.
Mr Rosen believes there is a unique quality to live broadcasts, admitting nostalgia for the days of the Wednesday Play on television. Live football is thrilling because "we don't know what's going to happen", and the arts could benefit from embracing the "sense of moment and nervousness" of live broadcasts.
Mr Rosen performs for 10,000 secondary pupils later that day, including fourth years at St Mungo's High in Falkirk. They submit a question just before the start, asking why he is writing a biography about Roald Dahl, and are thrilled when he replies minutes later.
English teacher Jane Palencarova had feared her pupils would be too old to enjoy Mr Rosen. But they are won over by his unexpected talent for rapping: "I think they'd imagined writers to be people who can't relate to others and sit in a corner with their typewriter."
A similar event last year did not work as well, she says, partly because of technical problems and partly because the writer was not as energetic: it takes a performer like Mr Rosen to keep pupils' attention from behind a screen.
Meet Our Authors is sponsored by Scottish Friendly Assurance. Other live events will involve Julia Donaldson, Eoin Colfer, Philip Pullman and Jacqueline Wilson.
WHAT SCHOOLS SAID
Gail Connick, St Gabriel's Primary, Inverclyde
"We were concerned about the reliability of the live link beforehand but found no problems on the day. The event was fantastic, Michael Rosen captured the attention of our school and one week later they're still talking about it."
Cathy Armstrong, Drumchapel High, Glasgow
"I had put out some of Michael Rosen's books on the tables . and one boy started reading out a poem he liked to another boy! (These were not remotely `swotty kids'.) After school one pupil from the event asked to read some of the poems she liked to our book group and we also watched the `Chocolate Cake' poem with both the group watching live and the book group after school."
Katrina Tulloch, Bonaly Primary, Edinburgh
"Children were enthralled by Michael's delivery which is so natural and fast-flowing. The children giggled their way through the presentation and didn't want it to end. Every stage was captivated and so were the staff."