About a million schoolchildren across Britain have taken part in a mass jump - but their feet failed to make the impact scientists had hoped for.

Their pounding feet seem to have caused just a "squiggle" on equipment used to monitor earthquakes.

At 1100 BST on Friday, at least a million children were jumping for a minute in a mass experiment designed to launch Science Year.

The experiment was taking place in school playgrounds as well as other venues across the UK.

A million children with an average weight of 7st 12 lb (50kg) jumping 20 times was predicted to release two billion joules of energy.

Scientists wanted to measure the impact on seismometers - machines used to monitor earthquakes - but did not expect it to register more than three on the Richter Scale.

At the headquarters of the British Geological Survey in Edinburgh, scientists noticed nothing untoward on their monitoring screens.

The survey's Dr Brian Baptie said that was much as he had expected.

Just a 'squiggle'

An initial look at data from other centres did reveal an intriguing "squiggle" in Cornwall.

But he said it would be some hours before all the information could be analysed.

Dr Ted Nield, from the Geological Society of London, said before the event: "Britain is hit by magnitude three earthquakes all the time - but you do not ever notice it.

The jump was organised to launch Science Year, a government-funded campaign which aims to promote science among pupils aged between 10 and 19.

It was recorded by the Guinness Book of Records as the "greatest simultaneous jump in history".

Among the places where The Giant Jump took place were Glasgow, Belfast, Cardiff, Cornwall, Bristol, and Newcastle.

They were linked by a live feed to London's Science Museum, where the official launch of Science Year took place.

At the museum, about a 100 teenagers from Archbishop Tenison's School in London and North Westminster Community School in London and Overton Grange School in Sutton leaped up and down for a minute for the sake of science.

Craig Burn from Archbishop Tenison's said: "It was really good to be part of a record attempt and know there were so many other people doing it."

Jarved Laher, from the same school, said: "It was good fun. It might make some people more interested in science."

Diego S-Burton, 15, from Archbishop Tenison's School, said: "It was well bad, a good experience and it was good to be part of such a big experiment."

The boys are taught science by David Bromfield, who is also a television presenter for BBC's Tomorrow's World.

He said he hoped Science Year would inspire more children to get into the subject. "Something like this can only encourage children to become interested in science."

That is what the government is hoping.

Speaking at the Science Museum, the Education Secretary Estelle Morris said she hoped more children - and especially girls - would investigate all the interesting careers that were open to scientists.

Free microscopes

She announced every secondary school would get a free electronic microscope to mark the start of Science Year.

And she said: "Science teachers have always deployed a range of techniques to inspire and motivate young people and I want to find new ways of supporting them in this.

The President of the Royal Society, Lord May, told the children and scientists at the launch that the science children learned in school was very different from the experience of working scientists.

"I hope that Science Year will show there is much more to science than memorising the names of plants and minerals," he said.

"People are looking for solutions to problems, going on voyages of discovery in looking for treatments for cancer, or helping to create better engines."

Science Year is being run by the National Endowment for Science, Technology and the Arts (Nesta) which was set up to promote innovation, with major partners the Association of Science Education and the British Association.