A bevy of windmills were on display at the Bala Bhavan at Cubbon Park on Sunday morning. Nearly 300 children between ages nine and 15 were here to demonstrate their homemade hand-held wind-energy generators as part of the Sunday Science School competition.

“Students were provided with basic raw materials — motor, wires and LEDs — to create a windmill and light as many LEDs as possible,” said Sujata Virdhe, director, Sunday Science School. The organisers had also set up a repair hub to help students whose windmills may have been damaged in transit.

While many students were seen comparing their projects, some were making last minute changes to their windmills.

“Our younger son, who is in class 5, is taking part in the competition but our older son, who is in class 9, was disappointed since he is too old for the competition,” said Jayachandran, a parent. His son Snehal connected the windmill to 75 LEDs. “Making the blades was the most crucial part. I failed thrice before I settled on using plastic and a tapered shape for the blades,” said Snehal whose brother helped him with connecting the LEDs and making the structure to hold the LEDs.

Windmills of all shapes and sizes were on display here. But a pink doll-house that was lit by 10 LEDs caught the eye. “My father helped me with the project. I had problems deciding on the material for the blades at first, but eventually found that the plastic ice cream box lid suited my requirements,” said Drishya Nair, a nine-year-old.

Five winners will be chosen over the next few days.