Pupils test world water in mass chemistry experiment
Children from hundreds of schools in Britain are taking part in what organisers say may be the biggest ever global chemistry experiment.
Students from around the world are testing the acidity of water from their local rivers and lakes.
The International Union of Pure and Applied Chemistry will collate the data into a map of global water quality.
Participating countries range from Australia to Slovakia, India and South Africa.
The project is part of the International Year of Chemistry 2011, established by the UN to mark the 100th anniversary of Marie Curie's winning the Nobel Prize for Chemistry in 1911.
The Royal Society of Chemistry said the data gathered would be of "genuine national and international use".
RSC President David Phillips said the initiative would "demonstrate the enjoyment that be gained from practical experimentation - also it will show that no one is too young to take part in science".
Schools in the UK are mainly carrying out their tests on the same day, Wednesday, but those in other countries will continue testing water and submitting results until the end of the year.
Organisers of the project said that so far, 430 teachers had registered on their website to upload data.
They estimate that 7,000 students from 40 countries are already involved, and expect more to join throughout the year.
Schools have been able to order kits explaining how to collect water samples, add a fluid indicator that will change colour depending on the acidity of the water, and compare it with colour charts to give a reading.
Some schools will also carry out a second experiment to test the water's salinity.Impact on wildlife
While the project is primarily aimed at children aged between 13 and 16, St Vincent de Paul Catholic Primary School in Stevenage was one of several primary schools taking part.
Head teacher Diann Ross said 60 children in year 3, aged about seven, as well as another 10 older children, had tested the water in nearby Fairlands Valley Park.
"They loved everything about it - the hands-on experience and working with real scientists," she said.
"Children always enjoy hands-on activities and in primary school it's often difficult to set up hands-on experiments. We don't have the equipment or technicians," she said.
The RSC said the tests were important because even slight changes in water acidity can reduce the hatching success of fish eggs and irritate fish and aquatic insect gills.
Some scientists believe a recent drop in amphibian numbers around the world is due to the effect of acid rain, it said, while heavy metals dissolve more easily in acidic water, and become more toxic when dissolved.
The RSC is currently calling for an increase in the amount of practical experimentation in UK schools, amid concerns that it may be declining.