This device usually consists of sequences of different objects, one triggering the action of the next. For example, several domino tiles placed upright. The first one falls and that makes all the others fall down too. The last tile releases an iron ball down a spiral whatchamacallit only to trigger the action of another piece, and so on. A friend of mine made a miniature version of something like it and we were wondering what it is called. Unfortunately, without knowing its name, I can't provide a picture.
This is called a Rube Goldberg machine.
A Rube Goldberg machine is a contraption, invention, device or apparatus that is deliberately over-engineered or overdone to perform a very simple task in a very complicated fashion, usually including a chain reaction. The expression is named after American cartoonist and inventor Rube Goldberg (1883–1970).
An example is Goldberg's "Professor Butts and the Self-Operating Napkin", which was later reprinted in a few book collections, including the postcard book Rube Goldberg's Inventions! and the hardcover Rube Goldberg: Inventions, both compiled by Maynard Frank Wolfe from the Rube Goldberg Archives. The "Self-Operating Napkin" is activated when soup spoon (A) is raised to mouth, pulling string (B) and thereby jerking ladle (C), which throws cracker (D) past parrot (E). Parrot jumps after cracker and perch (F) tilts, upsetting seeds (G) into pail (H). Extra weight in pail pulls cord (I), which opens and lights automatic cigar lighter (J), setting off skyrocket (K) which causes sickle (L) to cut string (M) and allow pendulum with attached napkin to swing back and forth, thereby wiping chin.
And here's one of my favorites: The machine in this Honda Commercial is all made from Honda car parts and demonstrates a high level of finesse.
I think you are referring to a chain reaction machine:
- A Chain Reaction Machine uses natural forces, like gravity and elasticity, to make something happen. The chain is a series of simple devices like a pulley or some dominoes that knock into each other. The idea is to put together a few of these devices so that they go off one right after the other, like a chain reaction. Once you put the first one in motion, the rest of the machine should go by itself.
Since the Heath Robinson and Rube Goldburg type answers have an additional implication of ridiculously or humously complicated I would like to add to the pot a "Domino Effect Machine".
The domino effect relies on a cascade of events but does not necessarily expand or run out of control which is the popular expectation of a "Chain Reaction" and may be very elegant in it's design.