One teen created a battery-free flashlight powered by heat from the user’s palm on the handle. Another build a flying robot inspired by fruit flies.

What will you dream up for this year’s Google Science Fair?

The free, online competition is open to students worldwide who are between 13 and 18 years of age. Prizes include a $50,000 scholarship, trips to the Galapagos or to LEGO headquarters in Denmark, and first-hand look at Virgin Galactic’s latest spacecraft.