How does this work? And then..?

My nephew explains to me how his solar powered toy helicopter works: "When the sun shines bright, the energy goes into the battery," he shows me. "And that goes through the wires into the propellors and they start turning..."
He describes to me an "invention" he is working on--it has to do with collecting rain water for a shower.
On the trampoline outside, while we enjoy the physicality of bouncing up and down for the sheer fun of it, my nephew points out to me that when we jump down, the springs of the trampoline are stretched and pulled down and when we jump up, they are released.
This kid turned 4 last month.

Science and how things work are his current interests, evident since he was a mere 2 year old.
While I couldn't care less how things work as long as they are working,  for him, it is an actually need to know: "How does it work?" "And then?" He always wants to know what more.
I gave him a book that my own kids had no interest in when they were younger. It's that great scary book by David Macaulay, The Way Things Work.  Advanced as it is, he loves it and requests bed time stories from it.
"I'm a builder," he pronounces.

My sister says she has to look up things all the time in order to answer his many questions.
Then there's his baby sister. She wants to see what he is doing. She wants to do what he is doing. At just 9 months, she is already walking which means trouble for the parents.  At the piano, she shoves my hand off the keys: SHE wants to play. She listens attentively to the sounds she is making, she grins at me. I try to play a note or two, she pushes my hand off again: "I'm doing this," her gesture suggests.

Another niece who is nearly 7 is obsessed with animals-reptiles in particular. She knows the latest on all types and she watches Youtube to learn more. She is also obsessed with rainbow loom and makes all sorts of intricate jewellery and even animal figures--the patterning and math involved is astounding. Her baby brother loves to dance and loves all things that fly—especially hot air balloons.

When given freedom to learn, children's interests become evident. It is simply a matter of watching, listening and exposing them to the myriad opportunities out there. Children with freedom to learn are unstoppable.