The practice of meeting in silence is at the heart of Quaker life. John Edward Southall, the 19th-century Quaker and printer, once wrote: "We cannot go through life strong and fresh on constant express trains." And at Bootham the silence is valued as an opportunity to think and reflect, to create inner space.
The meeting I attend at Bootham is fairly low key as exams are under way and the main assembly hall is in use. Pupils start gathering in the dining hall at 8.40am. They are full of chat, but not boisterous, and sit down at benches, tables or on the floor.
Ian Small wanders in and sits alongside his deputy, Graham Ralph. He looks around. Nothing is said, but the dining hall falls silent. It remains silent. Some pupils cradle heads in arms, others fiddle with bag straps, most just look down at the floor or stare ahead absent-mindedly. It is an easy silence that continues for minutes.
Eventually, Mr Small stands up and reads out a poem about final reckoning.
Then he sits back down and the hall falls silent again, and for longer. It is a deep, inner silence unperturbed by whirring fans and cooking smells.
Pupils are familiar with it, untroubled. The head and deputy shake hands, a signal for the meeting to end. The silence settles back into chat and pupils file out in courteous but unregulated fashion.
Most mornings the school assembles like this for readings and silence.
Every Thursday and Sunday it meets in silence only. No readings. On Wednesday afternoon, sixth-formers join sixth-form girls from the Mount school at the Quaker Meeting House in York for a half-hour silent meeting, though pupils moved to speak on any matter can do so.
It's not that all pupils are expected to have deep religious thoughts.
Indeed, Mr Ralph once confessed to a school meeting that he'd spent his silence thinking about where he'd left his Wellingtons that morning. Mr Small believes silence to be a unifying force for pupils from all cultures and backgrounds. "Whether you are Muslim, Jew, Buddhist or Catholic, you can come together in the silence with your own thoughts and reflections. It is a religious and moral experience - with a small r and a small m."
Alex Outhwaite, 16, came to Bootham for his sixth form after a troubled time at his previous school. "At first I thought, 'What the hell is going on here?' and then I just started to relax, let my mind go blank. You can just sit and think things through without being disturbed."
Ruth Drury, 17, a fellow sixth-former, came to Bootham when she was 11. "I used to worry about what I should be thinking about in the silence, but then I saw it as time for me, time to relax with my own thoughts, time out, which is essential. It's so easy to get caught up in the business of everything."