For as long as I can remember I always took things apart. I opened up watches, walkmans, flashlights, cameras, remote controls and toys, lots of toys.
As a kindergarten teacher, I see that disassembling something can teach a lot. The physical part improves fine motor skills, hand-eye coordination, strength and confidence. The knowledge obtained by by disassembling something is unique in a way that it can't be taught without hands on experience.
Before opening up anything, I first ask the children to describe what's inside, how it work and how would it look like. And I let them draw the inner parts out from their imagination. This stage is very important because it forces the child to stop and think, remember or imagine and become a part of the process.
After the kids draw the inside, I hand them tools and they start locating the screws, identifying their types and opening them, sometimes I help loosen them. After a few times a kid repeats that process, he or she will become more confident with it and will eventually be able to do it alone.
When everything is apart, we arrange all of the parts by types, I tell them the name of the parts, their purpose and we have a short conversation. I then ask the kids draw what they see in front of them. We compare the before and after drawings and talk about what we've learned.
Be aware of unwanted disassembling, some of the children are now locating screws everywhere and wanting to unfasten them, don't leave the screwdrivers unattended.