15-year-old builds flashlight powered by body heat: How her hollow aluminium tube generated electricity to keep an LED lit for more than 20 minutes

A 15-year-old Canadian student built a battery-free flashlight that uses the temperature difference between a warm human palm and cooler air to generate electricity. Her Hollow Flashlight used thermoelectric tiles to power an LED for more than 20 minutes.

Raccontata daeconomictimes.indiatimes.com