Complex Machine for Science Project

I really need help with this. It should be pretty simple and should not take long to build but my biggest problem is finding out what to make. I would really appreciate it if you guys come up with some ideas of what I can make, thanks.

Requirements:

3 steps: Meaning, for example, you push a marble, it hits a domino (1st step) and that domino starts something else (2nd step), then the something else ends it (3rd step).

Must have a beneficial meaning. In other words it has to be useful, something somebody would use.

 

Look up "Rude Goldberg Machine" - try googling it, watching some videos on YouTube, etc. Here's a link to get you started: http://en.wikipedia.org/wiki/Rube_Goldberg_machine

There are plenty of sites with good ideas for these kinds of machines on the web.

 

I have seen the Goldberg machine, but that thing is way too big, meaning I can't carry it to school, but I can probably make a smaller version with some parts missing, thanks.

 

you could build a machine that can unscrew caps off bottles or jars? not a can opener but one that can get the tough caps off?

 

Rude Goldberg machines are a generic term, not a specific "one" machine. There is, of course, the machines he himself created - but you don't need to do anything NEAR that level of complexity. You can take some inspiration from them, though - like, for example:
1) Drop a marble onto a track. Have it do some funky stuff, but eventually end up near the end of a table.
2) Have the marble drop from the table into a small cup.
3) have the cup set up so that it acts as a "pulley" -- have one end of a string attached to the small bucket, the other end attached to a light pointing up, and when the marble falls into the bucket (if it falls from enough of a height), the force should be enough to flip the switch. Eh?

 

A goldberge machine can be very small "push a golfball with a string in it. said golfball swings and knocks over a domino tower into a tub that presses the power button on a remote"

 

Complex machine, yet you want it simple? I dont get it. Try making a volcano, or some kind of light powered watermelon. I dont know.

 

Not a bad idea, I'll look into it, thanks.