Rube Goldberg Machines

Build a Rube Goldberg machine to pop a balloon

A Rube Goldberg machine is an exceedingly complex apparatus that performs a very simple task in a very indirect and convoluted way. It first appeared in Webster's Third New International Dictionary with the definition, "accomplishing by extremely complex roundabout means what actually or seemingly could be done simply." The expression has been dated as originating in the US around 1930 to describe Goldberg's illustrations of "absurdly-connected machines".

An example of one of Rube Goldberg’s original inventions is shown below.

Device to Keep You from Forgetting to Mail Your Wife's Letter

It starts as you are walking down the street, with your contraption around your waist. As you near the mailbox, the boot from the shoemaker's shop gets caught on your hook. It ends when a sign is pulled down in front of you, with the reminder, "You sap. Mail that letter." Don't leave home without one.

- 1 - The Assignment

The class assignment is to build a Rube Goldberg machine to pop a balloon. You will be working in groups of three, but your group doesn’t have to build the entire machine. (That would be too easy). You just have to build one small part of the machine.

In the modern world, whether we are building software, a LNG plant or boat, we rarely design and build the entire project ourselves. Instead, we break the project up into modules, build the modules separately and then fit these separate modules together to create the finished project.

Instead, you have to communicate scientifically with all the other groups – particularly the group building the module before you and the group building the module after you.

Your teacher will assign you the number of the module you will be building.

Module 1 will be built by the teacher (the teacher is group 1). It will consist of a “car” rolling down a slope with a piece of string tied to it. This piece of string will be the interface between module 1 and the next module. That is, module 2 will be powered by or triggered off by the piece of string pulling it.

Group 2, the group building module 2, will need to use the piece of string to power or trigger their module. As well as planning what their module will do, group 2 needs to decide how group 3’s module will be triggered off by module 2. Group 2 and group 3 will work together closely to decide how module 2 will interface with module 3.

Likewise, each group will work closely with the other groups in deciding how the modules will interface together.

The last group will design and build the module that will actually pop the balloon.

- 2 - How will you be evaluated on this assignment?

This is a group assignment and you will be evaluated as a group. For this reason, choose the other members of your group very carefully. At the end of the project, your group will present a report. You only need to submit one copy for the entire group.

Marks will be allocated as follows:

1. Planning: (10 marks) You will prepare a diagram of your module and a description of how it works. This must include details of the interfaces with the previous module and the next module. You must also say how you will test your module. (You don’t want to wait until all the modules are assembled before you test it – if it doesn’t work, then your group will stop the entire machine from working). 2. Construction: (10 marks) You will build and test your module. 3. Improvements: (5 marks) Your first effort will never be perfect. You will need to fiddle and improve. You will describe just how you improved your module to make it work better. 4. Final Assembly and testing: (5 marks) You will be judged on how well you work with the group before you and the group after you. (Marks will be deducted for impolite behaviour, arguing or showing lack of enthusiasm in helping others) 5. Bursting the balloon: (10 marks) If the machine actually works, then you will receive these bonus marks. 6. A scientific analysis of your module: (20 marks) You need to write half a page describing the scientific principles behind your module. You must identify any forces involved, what types of energies are involved, what energy transfers occur and what work is done. You will need to include a diagram of your module in this section and refer to this diagram. This can be the same diagram that you used in part 1, or it can be a different diagram (because of the improvements you made in step 3). On this diagram, you must show any forces and the direction they are acting in. You must also show any energy transfers involved.

In particular, you will need to address these issues:  Why can the entire machine run. This will require you to discuss the ideas of energy conservation and energy transfers.  Where is energy generated or replenished throughout the machine.  Where is energy lost throughout the machine.  What forces are involved and where can these forces be seen in the machine.  Where is work done in the machine.  For your own group’s module you will need to discuss what forms of energy are used and what energy transfers occur.

- 3 - Examples: Rube Goldberg Machines

Machine to pick a winner for a prize!

1. Turn the hand-powered "generator" 2. Motor lifts dog house 15. Magnetic ball rolls slowly through copper pipe 3. Gear dog walks out of house 16. Lands in basket and pushes down lever 4. Triggers mousetrap 17. Another lever sets off mousetrap 5. String on mousetrap spins gears 18. Mousetrap triggers Gauss Rifle (magnetic 6. Paperclip from gears releases bag of balls propulsion) 7. Bag pushes on lever 19. Magnets travel uphill, releasing last one through 8. Lever releases pink ball yellow tube. 9. Pink ball triggers mousetrap 20. Hits a set of marbles, that roll down the "pinball 10. Mousetrap pulls nail from yellow stick, dropping machine" a weight 21. Marbles knock over blue Lego piece 11. String on weight pulls lever up 22. Lego triggers mousetrap number four 12. Lever releases golf ball 23. Mousetrap pulls plug from bottle, releasing sand 13. Golf ball bumps ball down staircase 24. Weight of sand (eventually) turns on switch 14. Ball bumps tinker toy sticks

- 4 - 25. Switch powers motor that spins bingo cage. This releases a ball to pick the winner!

A machine to turn the page of a book!

The goal of the 1998 Rube Goldberg contest at the Museum of Scientific Discovery, Harrisburg, was to build a machine (with at least 10 steps) to turn the page of a book

- 5 - 1. Turn the handle on a toy cash register to open the drawer. 2. The drawer pushes a golf ball off a platform, into a small blue funnel, and down a ramp. 3. The falling golf ball pulls a string that releases the magic school bus (carrying a picture of Rube Goldberg) down a large blue ramp. 4. Rube's bus hits a rubber ball on a platform, dropping the ball into a large red funnel. 5. The ball lands on a mousetrap (on the orange box) and sets it off. 6. The mousetrap pulls a nail from the yellow stick. 7. The nail allows a weight to drop. 8. The weight pulls a cardboard "cork" from an orange tube. 9. This drops a ball into a cup. 10. The cup tilts a metal scale and raises a wire. 11. The wire releases a ball down a red ramp. 12. The ball falls into a pink paper basket. 13. The basket pulls a string to turn the page of the book!

A machine to put coins in a bank!

- 6 - 1. Release Chitty Chitty car with mouse driving it and it bumps a rubber ball. 2. The ball knocks down the dominoes. 3. The dominoes trigger the first mousetrap. 4. The mousetrap pulls a string to turn on a toy record player. The music is "Hickory Dickory Dock"! 5. The record player spins the colorful gears. 6. The gears wind slowly wind a string that pull up a paperclip. 7. The paperclip is no longer in contact with another paperclip, which breaks the circuit on an electromagnet. 8. The electromagnet releases a mouse in a car down the ramp. 9. The moving mouse runs into a string, making it vibrate. 10. The string triggers mousetrap number 2. 11. This mousetrap pulls a string which pulls a hook (paperclip). 12. The hook releases a red parachute man and he flies down the incline. 13. The man pulls another string from a tube. This string has a pencil on the end. 14. The pulled pencil/string lets a heavy ball drop down the tube. 15. The dropping ball pulls an attached string up, making another mouse "go up the clock". 16. As the mouse moves, two small ball bearings are released down a marble track. (His tail was holding them in place). 17. The ball bearings land on mousetrap number three. 18. The mousetrap pulls a wire to trigger the mechanical bank, and with a tiny picture Rube Goldberg watching closely, a dog puts the coins into the bank!