The latter is the most difficult of the three, says Tim Buckley, who is teaching Year 5 Tools for Thinking as part of an Oxford Brookes University research project involving 12 schools throughout the country. "But it's a chance for them to be as creative in their thinking as they want to be, to let their brains go wild."
Sometimes the least likely children produce striking contributions in this last category, he says. "One very quiet girl said, in the bus scenario, that she was worried that if the driver had to brake, he might fall over. I hadn't even thought of the driver. What does that make me think, in terms of what's going on in there?"
Another favourite strategy (also de Bono) is known as "CAF" - or Consider All Factors - where pupils think around a given proposition and list their ideas. Asked to "consider all factors when interviewing for a teacher", for example, pupils came up with a substantial and perceptive list of questions, including "Do they have an open mind?" and "Can they teach different ways of learning - straightforward and other types?"
Year 5 are also exploring philosophy with Manchester University lecturer, Mike Garfield. The children were given tests in critical and creative thinking last autumn, and will be retested this summer in an attempt to assess the impact of the project on their learning. But in the meantime, Year5 are discovering some of the benefits for themselves: "It does have an effect on people, and it really does make you think," says Rachel, aged 10.
"And it makes your brain warm up for something else."