Use the materials provided by your teacher to design, build, and refine a Rube Goldberg machine within the following constraints:
The initial step releases a steel ball. After release the device must operate without assistance.
It must use at least four different kinds of energy.
It must use the electromagnet you constructed earlier in this chapter.
The final transformation extends a spring or rubber band.
When operating your device, make suitable measurements to calculate the ratio of the output energy to the input energy.
Assessment
You will be assessed on the number of energy transformations and/or transfers in your device and the number of unique simple machines used in the design.
What is a Rube Goldberg machine?
Rube Goldberg (1883–1970) was a cartoonist who was best known for drawing fanciful and complicated machines that performed what was ultimately a simple task. In the example at right, the subject’s act of moving food to his mouth triggered a series of operations that eventually wiped his mouth with a napkin. You already saw a simple example in Prince Ludwig’s contraption on page 333. In a Rube Goldberg machine, humor is de rigueur!
Energy transformations
At the heart of any Rube Goldberg machine is a series of transformations of energy, such as gravitational potential energy, elastic potential energy, linear kinetic energy, rotational energy, magnetic energy, or electrical energy. Many Rube Goldberg devices use a variety of the six simple machines, too.
Design
Sketch out a basic design of your machine where you break it into individual subsystems and their functions. For each functional element, note where there might be more than one design that you will want to explore. Write down the energy transformations or simple machines involved in each subsystem.
Prototype
Construct a prototype of your design. Identify where human understanding, ergonomics, or economics influenced how you constructed the prototype.
Test
Test each individual subsystem and, once they work individually, progress to testing the entire machine. Document the performance through data, which might include taking video of the machine’s elements in operation.
Evaluate
Evaluate each subsystem as well as the overall performance. Are there parts of your machine that can be improved?
Revise
Write down design revisions and implement them.
Final evaluation
Your teacher will evaluate how well you accomplished the task and score your device.
Design a Rube Goldberg machine
Rube Goldberg (1883–1970) was a cartoonist who was best known for drawing fanciful and complicated machines that performed what was ultimately a simple task. In the example at right, the subject’s act of moving food to his mouth triggered a series of operations that eventually wiped his mouth with a napkin. You already saw a simple example in 
