Help requested for a middle school Rube Goldberg

Well, thru the wonder of the interwebs, China Bambina and 4 of her classmates have managed to waste several weeks on cute puppy videos and other dreck as they search for ideas for a 10 step rube Goldberg device.

Any good ideas for “ingredients” or “building blocks” for a fun device that doesn’t require intricate frames and engineering from parental units? I’ve got a few - clothes pin releasing rubber band, metal die car to bump dominos, dominos, marble on a rail, mouse trap as a trigger, paper towel roll as a rail for the marble.

Any other common items that can be tossed together?

Possible Finales

  1. China Bambina has a domino set thingy that can ring a bell
  2. Like to set off a mento’s rocket (drill a hole in a mentos, attach via thread inside a coke bottle, cut the thread, mentos drops into the coke, geyser)
  3. Other ideas?

Rube Goldberg machine. d’oh!

A couple of online examples


OK Go:

This Too Shall Pass.


OK, the second video isn’t really a Rube Goldberg machine, but it’s still cool.

Fixed thread title and moved from Cafe Society to MPSIMS.

At that age, KISS is really important (unless this is the annual “parents do a project which the kids take credit for” exercise). Paper towel tubes with marbles can control the direction of the marble. Scales that lift when the cup on one side is filled with water tend to be fairly reliable. Anything that needs to be hit “just so” to work is going to be disappointing. And remember it needs to move and get reset from home to school.

(I hate this project, its one of those ‘guarenteed to be disappointing for most kids and end up turning kids off from STEM’ projects.)

I guess you could use the proper shaped molding as a track for a ball too. I’m thinking of molding with a cross section of a 1/4 cut out circle. 2 sections of that against each other would make a nice trough for a ball. And if you used a metal ball, you could drive two nails into the molding. With a battery and some wire, you could rig a lamp to light or a buzzer to buzz when the ball rolled across the nails, completing the circuit.

Some sort of tripped trigger could release the energy in a stretched rubber band or a compressed spring. Pulleys might be useful too. Maybe a carefully dropped marble could close a barely open old time knife switch?

Imagine a thread spool on an axle. Wind some string around it and put a weight on the end. When the weight falls, the spool will turn. Attach some propeller blades to the spool.

Maybe some gears and cogs?

If this is for a competition (such as the Mission Possible event in the Science Olympiad), make sure you read over the rules carefully. Following the rules and achieving the required objectives are much more important than looking cool.

Also think creatively about ways you can accomplish the required tasks, and be ready to explain them to the judges. The judges want to be impressed; you just have to give them the opportunity.

Boy 2.0 just competed at State with his RG device - high school level, the required objective was to squeeze a proper-sized dollop of toothpaste onto a standard toothbrush, they came in second place. One of the more “fun” things his team used as a weight was a Matchbox car, which was released by some other element, went down one of the flexible racetrack pieces, around the loop-to-loop, and landed on a lever to release a gate that did something else. It was a little finicky to set, but would have been less tricky without the loop.

While it’s good advice to make sure you’re precisely following the rules of the project, I have to say that the whole point of a Rube Goldberg device IS to look cool. They are meant to be entertaining. If you don’t take ‘presentation’ into account, you’re doing it wrong. As a physics teacher, I’ve graded my share of these things and I always stress to my students, “Remember to design this for an audience. Make it interesting. Make it cool.” :cool:

Looking cool sure, but I’ve always thought of it as one of the earliest geek jokes, using an incredibly complex process to perform a trivial task…

That could be my favorite internet video in years. The earnestness and wholesomeness of that video just raises the bar on future Goldberg machines and more importantly on internet comedy as a whole!

If you like that video, I highly recommend The Castle which is streaming on Netflix currently. It is a Australian mockumentary and has an early Eric Bana. It has the same humor- using earnest characters and selling them really well while not going for easy jokes. It is a very good silly and even my kids love it.