Here's an idea - a cosmic ray detector to make for £40

Holly Batchelor, 18, a pupil at the Mary Erskine School in Edinburgh, made her own cosmic ray detector - out of a plastic fish tank, an aluminium sheet and some felt - to win the Intel International Science and Engineering Fair's (ISEF) First Award for physics and astronomy.

Her cloud chamber device, which makes the particle trails of the rays visible, cost less than 40 to make - far cheaper than commercially available machines - and she hopes this will enable schools to build their own versions, inspiring more young scientists.

Holly also studied the energy and angle of cosmic rays, which come from the Sun and supernovae explosions.

This has recently become a hot topic, because it is thought the rays have an effect on cloud formation and climate change.

The teenager was awarded the prize at the event, which is the world's largest pre-college science festival, in Albuquerque, New Mexico, after judges picked her ahead of the winners of science fairs all over the globe.

"I couldn't believe my ears when they called out my name," she said. "It was a total shock."

She won 1,500 in prize money and is to have an asteroid named after her. She will also have a paid internship this summer at Agilent Technologies and go to a conference in Budapest.

But she said: "More than the prize money, I love the idea of having my name in space forever. It's a huge privilege."

Holly had planned to be a fashion designer, but she is going to St Andrews University to study physics instead.

"I've really only looked at particle physics, but the other branches [of physics] look like a good laugh, too," she said.

She won a place at the international final after winning the Crest Science Fair, run by the British Association for the Advancement of Science (BA).

Sharmila Banerjee, young people's programme manager at the BA, said: "Holly's infectious enthusiasm for science, coupled with her exceptional scientific skills and ability to explain the work clearly, made a big impression on both the judges.

"They were also very impressed with the outreach aspect of Holly's project.

"Since the cloud chamber she designed can be constructed at a fraction of the price of existing equipment, far more schools will be able to afford one."

Holly, who has just completed advanced Highers in maths, physics, applied mechanics and product design, said a pleasant experience in education had been important.

"I've always enjoyed school. I think that helped," she said.