What is Stealth?  Make your choice:

1.  it is teaching a child a topic or concept without them know it!
2.  an object that is not detectable, but it really is there!
3.  both of the above.

1.
Can we really teach our children without them realizing they are learning a "school topic" or life lesson?
Sure.   Read this person's blog to see the fun they had learning-   build a pendulum in your living room.
Stealth learning may not always appear orderly, but it’s natural and it can work!   It doesn’t have to be used exclusively, but it’s worth trying now and then and seeing how it might work for you and your child.
Stealth Learning 

2.
As you might expect, hiding a giant plane is no easy task. Northrop Grumman, the defense firm that won the bomber contract, spent billions of dollars and nearly 10 years developing the top secret project. The finished product is a revolutionary machine -- a 172-foot wide flying wing that looks like an insect to radar scanners! The craft is also revolutionary from an aeronautics perspective: It doesn't have any of the standard stabilizing systems you find on a conventional airplane, but pilots say it flies as smoothly as a fighter jet.   The B-2 bomber has a completely different design: It's one big wing; it is like a boomerang.
BUT how does the B-2 fly and how does it vanish?   LOTS of  MATH and science learning needed for this job.

Shall we make it stealth learning or book learning?