Three teenagers from Ireland have won the grand prize at this year's Google Science Fair.

Ciara Judge, Émer Hickey (both 16) and Sophie Healy Thow (17), who are all from Kinsale Community School in Cork, scooped the top honour at the competition in California.

As part of their winning research, the trio investigated the use of natural bacteria to assist food production by increasing crop output.

The grand prize includes a 10-day trip to the Galapagos Islands with National Geographic Expeditions, an experience at the Virgin Galactic Spaceport and $50,000 in scholarship funding.

Émer's father Peter Hickey tweeted his joy at the girls' victory earlier this morning, with the hashtag 'OneProudDad'.

Google Science Fair Winners - my daughter Emer and her team-mates Ciara and Sophie - #oneProudDad pic.twitter.com/P1AUbGWS7G — Peter Hickey (@peterhick) September 23, 2014

As part of their winning project, Ciara, Émer and Sophie investigated the use of diazotroph bacteria as a cereal crop germination and growth aid. They carried out an extensive study of its impact on the germination rate and subsequent growth of the cereal crops wheat, oats and barley, and found it accelerated crop germination by up to 50%, and increased barley yields by 74%.

Ciara, Émer and Sophie explain their project:

More on the project here.