Step by Step
“The crux of the design process is creating a satisfactory solution to a need. The need may be to improve an existing situation or to eliminate a problem. In any case, it is what engineering is all about—using knowledge and know-how to achieve a desired outcome.”
Lee Harrisberger, Engineersmanship… The Doing of Engineering Design
Engineering projects involve creative problem solving, and they are not hypothesis testing. Each engineering design, software application or device project should have a clear engineering goal which can fit the following model statement:
“The design and construction of a (engineered product) for (target user) to do (some useful function).”
Where can you get project ideas? You may get suggestions from teachers, advisors or mentors. Be sure to use the web (www.science-fair.org, www.sciencebuddies.org, www.madsci.org, ISEF Science Project Resources) for inspiration, however your idea should be original. Quality entries from previous fairs are good sources of ideas and best practices. Some high school technology curricula address the engineering design process, and many college and professional engineering societies have on-line resources.
You will use the engineering design process to create your fair entry. This process is typical of those used by practicing engineers; the definition of terms and the number of steps may vary, but these are “essential steps.” Your very first step is to start a project notebook in which you will record every step of your process and the results of your design efforts. The process is iterative, meaning the designer will often repeat steps until he or she is confident the design will meet the needs. Note: the terms product, invention, project, design, and solution are often used interchangeably in Fair Guidelines.
The Engineering Design Process:
- Define a need; express as a goal
- Establish design criteria and constraints
- Evaluate alternative designs
- Build a prototype of best design
- Test and evaluate the prototype using the design criteria
- Analyze test results, make design changes, and retest
- Communicate the design
Step 1. Identify a need
The need (also called the problem you are solving or the Engineering Goal) is frequently identified by customers–the users of the product. The customer could be a retail consumer or the next team in a product development. Customers may express needs by describing a product (I need a car) or as a functional requirement (I need a way to get to school). The need should be described in a simple statement that includes what you are designing (the product), who it is for (customer), what need does it satisfy (problem to solve), and how does it improve previous designs (easier to use, less expensive, more efficient, safer).
Step 2. Establish design criteria and constraints
Design criteria are requirements you specify that will be used to make decisions about how to build and evaluate the product. Criteria are derived from needs expressed by customers. Criteria define the product’s physical and functional characteristics and must be declared as a measurable quantity. Some examples of quantitative criteria include length (in cm, km, etc.); mass (in mg, kg, etc.); velocity (in m/sec, km/hr., etc.); and ruggedness (able to withstand an impact force of x Newtons). Some examples of quantitative accuracy include, ‘…fewer than y errors per mSec…’ or ‘…fewer than z particles per liter of fluid….’ Constraints are factors that limit the engineer’s flexibility. Some typical constraints are cost, time, and knowledge; legal issues; natural factors such as topography, climate, raw materials; and where the product will be used. Good designs will meet important design criteria within the limits fixed by the constraints. Good designs are also economical to make and use because cost is always a design constraint!
Step 3. Evaluate alternative designs and create your test plan
Your research into possible solutions will reveal what has been done to satisfy similar needs. You’ll discover where knowledge and science limit your solutions, how previous solutions may be improved, and what different approaches may meet design objectives. You should consider at least two or three alternative designs and consider using available technology, modifying current designs, or inventing new solutions. Superior work will demonstrate tradeoff analyses such as comparing the strength vs. cost of various bridge-building materials. It’s important to document in your project notebook how you chose and evaluated alternative designs. Can you defend your choices to the judges?
You will develop an initial test plan describing how you will test the design criteria and constraints you listed in Step 2. Many engineering design projects will require pre-approval from the SRC. A risk assessment form (3) is required for any project using hazardous chemicals, activities or devices and microorganisms exempt from pre-approval. If you will involve humans in your product testing, you will be required to fill out a Human Participant Research Plan. The exemption to this requirement is if your invention does not pose a risk, and it is being tested only by yourself or your team members.
STOP! You must complete an Application Form including a completed engineering template, risk assessment form and/or Human Participant Research Plan as appropriate. Obtain approval from your teacher and the SRC (Scientific Review Committee) BEFORE you build your prototype.
Step 4. Build a prototype of best design
Use your alternative analyses to choose the design that best meets criteria considering the constraints, then build a prototype. A prototype is the first full scale and usually functional form of a new type or design.
Step 5. Test and evaluate the prototype against important design criteria to show how well the product meets the need
You must test your prototype under actual or simulated operating conditions. Make sure you test all of your criteria and constraints to evaluate the success of your prototype. Customers are usually involved in product testing so be sure you have SRC approval if people are involved.
Step 6. Analyze test results, make design changes and retest
Testing will disclose some deficiencies in your design. Sometimes the testing fails completely and sends the designer “back to the drawing board.” Make corrections and retest OR prepare an analysis of what went wrong and how you will fix it. As always, document your analyses, fixes, and retests in your notebook.
Step 7. Communicate the design
The designer’s real product is the description of a design from which others will build the product. Use your notebook and the fair exhibit to communicate the design to your customer and the judges. Your product description will be conveyed in drawings, photos, materials lists, assembly instructions, test plans and results. Consider listing lessons learned so future designers need not repeat any of your “frustrations.” You’ll have clear instructions on how to produce your design, along with production cost estimates.
Step 8. Prepare
Prepare your engineering project exhibit board. See the Project Display Rules and Helpful Display Hints for a successful project board.
Step 9. Prepare your abstracts and compliance checklist
You will need to bring to Check-In day:
- 1 copy of your Project Abstract
- your completed Compliance Checklist
- your project board
- research notebook
View the Engineering Workshop slide presentation for additional information.
