Featured Course: Invention by Design
On page two of his book, Invention by Design, author Henry Petroski says that “The idea of design and development is what most distinguishes engineering from science, which concerns itself principally with understanding the world as it is.” That, in a nutshell, is what this course is all about. Students start by examining the design of everyday items like the lowly paper clip and work towards the culminating course project; the design of a realistic roller coaster. Along the way you’ll study the basic physical forces that constrain design choices and that knowledge will come in handy when designing your coaster. You’ll be asked to create a design that balances fun, safety, and economic viability; and you’ll soon discover that there’s a fine line between acceleration rates and g-forces that are fun and those that do bodily harm to the riders! As the lead engineer for the project you can’t just hope that your design is safe, you’ll have to prove it.
Students in this course explore the development of the built world by investigating inventions from the paperclip to the roller coaster. You’llll discover the “principles and processes that turn thought into the many things that define our made world.” The course requires students to read and think about science, engineering, invention and design, create journal entries based on their reading, discuss related issues with their classmates, complete a number of exploratory activities, and create and solve problems.
The course organized around the physical principles that typically constrain design choices:
Module 1 About Science and Engineering
Module 2 Motion
Module 3 Force
Module 4 Energy
Module 5 Gravity
Module 6 About Invention and Design
Featured Activity: Design A Roller Coaster
The culminating activity for this course is the design of a realistic roller coaster. This excerpt, taken directly from the instructions in the course introduces the activity;
In this series of assignments you will take on the role of design engineer for a firm designing a new roller coaster for an amusement park.
Your task is to balance the sometimes conflicting requirements provided by the park to create a design that is safe, fun to ride, and economically viable.
Because of the complexity of this task, you will tackle it by breaking it down into three phases, each of which is also a course assignment.
The design of a roller coaster is a complex undertaking.
You must first select the building materials you will use and that choice will limit your design options.
The costs, both for construction and for daily operation, will also vary depending on the building material and design that you select.
Taken together your materials choices and design will determine the “fun factor” of your ride and the subsequent expected revenue. Wooden coasters are slower, and they do not typically have loops, so patrons of wooden coasters expect a longer ride.
Steel coasters support higher speeds and loops, but construction costs are higher. Your goal is to make a compelling proposal that the amusement park will accept. To succeed, all of these inter-related factors must be taken into account.
In a later assignment you will model the physical characteristics of your design by calculating the forces at play on the track, the cars, and most importantly the riders.
The roller coaster software you will use allows you to simulate and “test ride” your designs, but ultimately you will need to demonstrate that your design is safe by showing that it does not exceed any of the force limits imposed by the project requirements. You’ll also have to show that there is a reasonable expectation that your ride will generate a profit. To meet these goals you will model both the economic and physical characteristics of your design. Model templates (spreadsheets) are provided to get you started with this.
The instructions refer to “the roller coaster software” and the culminating course activity makes extensive use of the Ultimate Ride Disney Coaster software. While this software is first and foremost a game, it includes a design and build mode that provides detailed information about the performance of the track designs you create. This allows the software to be used as a design tool and as a simulation tool. You “build” your designs by putting pieces together much as you would build a model train layout. There are a variety of track piece types and the designer/builder provides detailed control over the length, radius, slope, and placement of each piece. As each track piece is added the software provides metrics, including; the length of the piece, the slope angle of the piece, the radius, the speed at which the car will leave the piece (based on the design to that point), and the forces that will be exerted on the rider. In addition, when you take a virtual ride on your coaster the software provides instant feedback on the speed of the car and the forces a rider would feel. You can even turn off “friction” introducing some intriguing design possibilities. The feedback you get as you build and test your ride allows you to show (hopefully) that your design meets both the fun and the safety guidelines specified by the amusement park.