The chart of the children's responses on the big screen shows that three-quarters would or might, "It depends on the prize."
"Bad choice," Ms McNeill, of Setpoint Scotland West, tells the fascinated class. "This was a real competition run by a stupid newspaper. The prize was two theatre tickets, but the winner didn't use them because she couldn't sit down. She spent the next three months in hospital."
From his vantage point at the side of the class, Steve Brindley, the Setpoint Scotland West director and former teacher, keeps one eye on the computer analysing the signals from the handsets each child holds, while the other watches for cues to send the results to the screen. He and his team of science communicators, based at Glasgow University, have been using the interactive technology for almost a year.
"We've been amazed by some of the things it has shown us about how kids think and what they learn, or very often don't," he says. "Watch this part, for instance."
Ms McNeill asks the class for the temperature at which all the water in a bowl will turn into gas. "Press 1 on your handset for 0C. Press 2 for 50C.
"Just wait. Most will get this right," Mr Brindley predicts.
Sure enough they do, although a sizeable minority chooses 0C.
"Now watch this," he says. "Debs has asked for the temperature that the water will turn to a solid. I bet their answers are all over the place."
Indeed they are, with - 100C and - 10C just as popular as 0C.
Whether the children's difficulty lies in the scientific concept of freezing or the mathematical concept of zero will take more research to determine. But the technology has almost effortlessly pinpointed an area where teaching should change so that better learning can take place.
"There is an even more fundamental point," says Mr Brindley. "Watch this."
Ms McNeill asks the pupils for the gases that make up air and a forest of hands goes up.
"Oxygen," says one.
"Carbon dioxide," says another.
"Gravity," offers a lad with a bit of homework to do.
Now Ms McNeill asks the class to select which of these four gases makes up most of the air in the room. Almost instantly the screen shows that the majority believe oxygen is the main component.
"We get the same response from every class we work with," says Mr Brindley.
"They have all been taught that there is much more nitrogen than oxygen in air, but they haven't learnt it.
"Before I had seen that feedback, I would have asked an open question to get their prior knowledge, someone would have given me the correct answer and I would have moved on, leaving most of the class behind me."
In the light of the interactive voting feedback, Setpoint lessons and shows have been adapted to address some of the misconceptions children have. To reinforce the fact that air is mostly nitrogen, for instance, Ms McNeill displays a memorable image of coloured balloons with faces. On testing the class again at the end of the lesson, she is rewarded with a dramatic shift in class perception. The majority have now learnt what she was trying to teach.
There remains 10 per cent who still get it wrong. "But another great feature about IVS is that it records and tabulates the responses of individual children," says Mr Brindley. "So the teacher can then address their particular problems and guide them in the right direction.
"I have been shocked by what IVS is showing us. Often the way we are teaching is confusing the kids. We can now see where that is happening and put it right.
"I think it's a brilliant educational tool."
Stephen Brindley, tel 0141 330 6396 email firstname.lastname@example.org scotland.org.uk