A SIMPLE glass of water is being hailed as the reason for an improvement in test results for pupils at an Edinburgh school.

Children at Corstorphine primary school have been encouraged to sip water throughout lessons in a pilot scheme to boost their concentration and performance.

And the unique experiment in ''brain hydration'' has been praised by school inspectors after it showed remarkable results. Now they hope to encourage other schools to follow the example of the small primary school and introduce water into the classroom for children across Scotland.

Deputy head teacher Carol Wood introduced the brain-boosting practice after reading about similar experiments which had been carried out in American schools.

Neurologists claim the brain works by connections made between neurones - cells which conduct nerve impulses - and these connections work more efficiently if the brain is well hydrated.

Mrs Wood said drinking water throughout the day means there is a more efficient electronic and chemical action between the brain and nervous system which heightens concentration.

She said: ''Children do have quite a long day. Some have the classic milk at break but some bring in juices which are not so good for rehydration. Now we are actively encouraging children to drink water during the day.''

Mrs Wood said since the water bottles had become a fixture on the pupil's desks national test results have improved. She said: ''We know that we have more than exceeded our targets for national tests and we have certainly reported an increase in our attainments.''

In a recent review of the school, inspectors said the school should continue to research this aspect of the children's learning.

Mr Ian Smith, a former researcher with the Scottish Consultative Council on the Curriculum who is now an education consultant, said he believed sipping water could make a significant difference to the child's learning.

He said: ''Most research says it is critical that the brain is not dehydrated, because if it is dehydrated we do not learn so well. One of the key things we know about how the brain works is that it is by laying down messages between neurones and those connections use water. The brain as a whole cannot function effectively if it is dehydrated.''

But Dr Christine MacIntyre, an expert in child development at Edinburgh University expressed scepticism at the experiment. ''I am quite surprised. I'm thinking if you fill them up with water they will want the toilet all day. It sounds a little far-fetched.''