Black Box Mystery

The black box used in 8th grade science.

In class we are examining the water exchanger device. We are calling this the black box activity because we really don't know what is inside the box. The following is a description about black boxes from Wikipedia:

In science and engineering, a black box is a device, system or object which can be viewed solely in terms of its input, output and transfer characteristics without any knowledge of its internal workings, that is, its implementation is "opaque" (black).

As I showed the class today, when I put 100 mL of water in the funnel only a small amount of water <5 mL came out. 

What is mysterious about the black box? 

What would you like to know more about the black box? 

Leave a comment about the black box!

http://en.wikipedia.org/wiki/Black_box