A few years ago, when college tutors could not think what written work to set trainee teachers, they asked students to write an essay on "The changing role of the primary teacher." It was a safe bet as the role was always changing.
Coping is a daily part of teaching. We are all aware of the weekly calls for teachers to be tougher, meet the challenges of the 21st century, satisfy growing parental demands, help Britain compete internationally, compensate for poor home backgrounds.
The traditional role of "teacher as transmitter of knowledge" has undergone several changes. Since the advent of the national curriculum, primary teachers have had to become a font of all knowledge. "Please miss,where's the Indus Valley?" "Miss, why doesn't plastic go rusty?" "How can you work out the probability of winning the lottery?" It is a far cry from tadpoles and sticky buds.
Design and technology has really stretched teachers. Research at Exeter has consistently shown it to be the subject that teachers are least confident about. If you followed the curriculum literally you would only teach one subject a week: technology. After your young pupils had finished selecting materials, designing and making objects, evaluating and improving them, there would be no time for anything else.
The first time I taught technology, I asked the school's deputy head if there was anything I should know. "Yes", she said. "In infant schools in this education authority you can't use scissors that cut." Thanks.
It was a pity that cookery became part of technology. One national curriculum technology guru enthused to me, "It's all-embracing. You can do business studies as well. For example, you can design, make, and then market a beefburger."
This was bad news to someone who saw cookery as an art. (1) Design a beefburger. A round one, maybe? (2) Select materials. Beef perhaps? (3) Make, evaluate and market it. I don't think the public will want to buy cork table mats enriched with the contents of Darren Rowbottom's nose.
The "teacher as scavenger" role has also changed. When my children were young I sent in Vim containers. These came back painted purple with Rice Krispies glued to them, labelled Star Ship Enterprise, or Kevin Keegan, I couldn't tell which. Now teachers say, "If you have any CD-Roms you're throwing away, bring them in."
Another developing role is that of "teacher as information technology expert". Staff who got nose bleeds turning on their old BBC computers are now expected to be spreadsheet wizards and Internet surfers.
Two roles have not changed in the slightest, however. The detail may be different, but the roles are the same. The first is "teacher as busker". The ability to think on your feet, get out of scrapes, cope with the unexpected, is as challenging as it ever was.
I once presented a live Radio 4 series with broadcaster Eric Robson. At the start of each show, the producer would go through that week's disasters - lack of link-up with the remote studio, a broken microphone, poor acoustics, or whatever. "Never mind," Eric would say. "We'll busk it."
The second unchanging role is that of "personal relationships expert". Primary teachers are renowned for positive relationships, both inside and outside the class. If these went amiss the consequences would be drastic.
As we buskers love to sing:
"Two lovely black eyes. Oh what a surprise. Only for telling a man he was wrong. Two lovely black eyes."
Ted Wragg is professor of education at the University of Exeter