During the demo, just take a wire, wind it around your hand a few dozen times, connect the ends to the LED, and put it close to a wireless Qi charger. It should light up. Its pretty cool to produce light just with wires.
Now if you reverse the concept and create a board full of Led rights and wound up wires, could you wave your hand (with the Qi charger) and get the lights light up based on your hand movement?
Kids love superpowers. If you use technology to simulate superpowers and make it seem easy, you will inspire them to become more curious.