My day began at 8.15am - half an hour later, I was to learn, than Chedel's. She arrives at 7.45am, to print out her lessons, discuss plans with her colleagues, and prepare her classroom for the day ahead. But this Tuesday in November, we sit in the staffroom and chat. Educational principles are all well and good, but if I was going to spend a day in a classroom, I wanted to know the practical stuff. Like what happens if she has to go to the loo during class? "We get very good at holding on," she says. Even during school holidays, her bladder knows 11.15am is bathroom time. Then there is the heavy responsibility of being in charge of the welfare and education of a class of seven-year-olds. Teachers can't zone out, or take a random day of annual leave to finish their Christmas shopping. If they've had a bad night's sleep or a big night out, they can't duck out for a bacon and egg roll. The kids are energetic, tireless and hungry for stimulus. A teacher's mental cogs need to be in good condition; according to a seminar given recently to Glebe Public staff, each teacher makes 1500 educational decisions a day.

Chedel describes her day as "constant triage"; the endless little decisions about how to act in any moment. "Do I want this battle? Do I ignore her? Do I keep pushing ahead with this lesson, or do I scrap it? Thinking on your feet is a big part of teaching. Dominique Chedel teaching her class at Glebe Public School. She describes her day as "constant triage". Credit:Louise Kennerley "You make deeper decisions when you're planning a lesson." I ask her whether the constant need to be "on" is the worst thing about teaching, privately thinking how draining it must be. Actually, no. For Chedel, the worst thing is nits. "I have dreams about nits and I have dreams about losing my teeth, because the [students] come up to me and show me their wobbly teeth," she says.

Loading After Chedel has been prepping for an hour-and-a-half, the delightful kids of 2C file into the classroom from morning line-up and tackle the first task of the day, which is splitting into reading groups assisted by two support staff and a parent volunteer. Afterwards, they sit beautifully as they listen to a recording of Dorothea Mackellar recite My Country, and then write their own rhyming "rap". They're marginally less focussed as they group penguins together in an exercise that introduces them to the concept of multiplication. But as the day wears on, they become fidgety - they're only seven, after all - and Chedel's sentences are increasingly peppered with phrases such as "sit on your bottom" or "shhh".

Even as we sit and chat about her experience as teacher while the students are occupied with an activity, our conversation goes a bit like this. "It is the best job," says Chedel. "You play such an important role for them GUYS I DON'T THINK WE NEED A BALL IN HERE." By late afternoon, she has the familiar parental problem of struggling to finish a sentence without interruption. When the fidgeting becomes too much, she uses her favourite - and remarkably effective trick - of singing a "look and listen" song, and the students all join in. Patience, she explains, is a key virtue for teachers. But so-called face time is just one part of the job. Much of her work is done outside the classroom, when she and her colleagues think about how and what their students should be learning, and reflect on their day to learn their own lessons about what worked and what didn't. Even the most carefully planned lesson can derail in the classroom. It's a bit like plotting a course on a map then taking to the high seas.