In Japan I saw a simulation of internet based communication in the The National Museum of Emerging Science and Innovation (Miraikan). It attempted to replicate ascii characters moving along a 8 part wire using combinations of marbles rolling along.
I've just finished reading Charles Petzold's book, Code: The Hidden Language of Computer Hardware and Software. In it Charles explains building relays into gates, gates into logic components, and logic components into computing machines.
I wondered if a mechanism existed that simulated a switch using marbles.
My question is: Is it possible to explain a transistor (or vacuum tube or relay) using a marble-based switch for students?