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The Beginner's Guide on How to Build a Rube Goldberg Machine

How to Build a Rube Goldberg Machine
In his life of 87 years, Reuben Goldberg had many talents to show off with. One of them were his witty political cartoons, for which he earned the ire of many people during World War II. None of his ideas however, were as ingenuous, as wacky, or as complicated as the Rube Goldberg Machine. You cannot expect to understand what it is until you see one in action or build one yourself.
Arun Prabhu
Last Updated: Sep 25, 2017
In essence, a Rube Goldberg Machine is a contraption that will perform the simplest of tasks in the most complicated way imaginable. You have probably seen examples of this in many movies, where the crazy scientist pushes a button to start a mass chain-reaction that runs around his house for a long time, using a ton of gadgets, gears, pulleys and small cars, in the end cracking open an egg over a pan on a stove! This is what most Rube Goldberg Machine enthusiasts are inspired to build. Of course, the difference in real life and the movies if a lot of editing, but we do have the Guinness World Record for the biggest Rube Goldberg Machine, a wicked device that works in 244 steps, for more than 2 minutes, which took 3,500 hours to build, all to just water a plant! Proud are the members of the Purdue Society of Professional Engineers who entered the 2011 Rube Goldberg Machine contest! How to build a Rube Goldberg machine will eventually be limited by the materials you possess, so be sure to get extra!

To aid you in the effort in building a Rube Goldberg Machine, I have written a few guidelines and tricks that you can use. There are many ideas that you can search for or think of yourself. I have described one later that will help you start off with your own ideas.
How Einstein and Newton Help You Out
The laws of Physics explain all that goes on around you in the most simple (or as we figure out in college, intensely complicated) method. The laws of Physics are your sharpest tools to build a successful Rube Goldberg Machine. The two that you will need the most are Gravity and Momentum.
They will often go hand-in-hand to work against each other, to make your machine carry the connecting elements, or as I call them, the 'Travelers', across the machine and towards the final goal. Remember these basic rules:
◉ Gravity will pull the traveler down, it will build 'Momentum', and will then work against 'Gravity' itself to climb up. Use this to knock through a barrier or initiate a new traveler, or to help the traveler climb up towards the next part of the machine.

◉ It may be useful to know that

● Momentum = Mass × Velocity
● Potential Energy = Mass × Height of the traveler above the base level × Acceleration due to gravity
● Kinetic Energy = (Mass × Velocity2 ) ÷ 2.
Yes, I'm a math nerd who likes to show off once in a while, but two minutes on the calculator will give you the numbers needed to get the best results. Use these and a few trial runs to perfect each part and make a Rube Goldberg Machine.
Dissecting a Rube Goldberg Machine
If you will examine each moving mechanism of a Rube Goldberg Machine, you will notice that there are three vital ones - the pulley, the dominoes, and a ball as a traveler. Using the proper counter-weight, the pulley is excellent for pulling your traveler up or gently letting it slide down. For example, a traveler will land in a cup, act as the counter-weight, and pull the new traveler, which is kept in another cup on the other end of the pulley, upwards. The cup may be positioned such that on reaching the top floor, the cup will tilt and slide the traveler onwards. Dominoes will always be found in a Rube Goldberg Machine. They are difficult to put up, but highly rewarding to be brought down with accuracy. Face it, it's just fun to watch a length of dominoes collapsing and cascading, feeling like the grand destroyer of all things, twiddling your fingers in delicious satisfaction! Dominoes may also be curled around the machine, instead of a regular straight line. You can also use pivots or levers so that the last domino that falls from one stack will hit the lever, which will rotate around a pivot and knock down the second stack. The ball is the most widely used traveler you will see, and for very logical reasons. It's round, moves fast enough to provide good momentum, can move around inside tracks or grooves, and all that. So whenever in doubt, throw a ball into the thing.
Building Your Own Rube Goldberg Machine
With all the basics covered, let's now build a Rube Goldberg Machine! First up, the end result. Sounds weird and pointless, but thinking of the simplest and most common thing you do, always, got me thinking of making it that much complicated. Be it watering a plant like the guys at Purdue, cracking open an egg, filling a bowl with cereal (This is the one I tried and will explain. The machine spanned across a long shelf in my kitchen.), take your pick or think of a new and funny one. Now to making it happen.
  • Starting at a half-pipe angled downwards, drop the ball into it from the higher end.
  • The ball rolls, reaches an S-shaped stack of dominoes.
  • The last piece springs a mouse-trap, which is connected to a string wound around a pulley.
  • On the other side of that pulley is a spoon, in which rests another ball, that snaps upwards, throwing the ball ahead. (This part took me a long time to perfect. It helps to keep the mouse-trap rooted to its place and the pulley firmly planted to the top.)
  • This ball lands into a funnel (I managed to land the ball in the side of the funnel, making it roll around in the funnel for a long time. Very cool to watch.), loads onto an angled half-pipe.
  • It rolls down and falls on one end of a see-saw, on the other end's tip of which rests ¼ of the base of a cereal box.
  • The top side of the box is hooked and stringed onto a pulley, the other end of which is a counter-weight (It will be tricky as the weight of the box has to be the same as the counter-weight. You have to search for the perfect dead-weight, and the cereal box must always be full). This is so that the box won't just fall into the bowl which I kept. The cereal box will instead tip over (According to the impact of the ball on the see-saw and the dead-weight), just enough and pour the blessed cereal into the bowl.
I also managed to build the same track on the above machine that poured milk from a carton into my bowl.
A ball may not be the only traveler in the machine. Feel free to use anything that can, well, 'travel' around the course, like a toy car, darts (carefully), maybe even helium balloons. All in all, the concept of the Rube Goldberg Machine is meant for having fun with it. The machine you build will be bound or unbound by your own imagination and the tools at hand. Whether a good way to pass time or as a display of your abilities in crafting and imagination, the Rube Goldberg Machine will be a definite means to make the best of them!