Resource: Automatic Door Opener

Creativity and flexibility go a long way in engineering. Not only does an engineer need to identify the problem to be solved and generate solutions while following design constraints, he or she must also be ready to adapt and improve the design through testing and evaluation.

Before an engineer builds and tests a prototype, careful thought and planning have gone into its design. After first identifying the problem that needs to be solved, the next step in the design process is to brainstorm ideas and come up with an initial design concept. Engineers need to consider many things when developing a design, including the materials to be used, how they will be assembled, and how the product will look and function.

In this video segment, two teams are presented with a design challenge — how to open their bedroom door while lying on the bed. As the teams brainstorm solutions, they must also keep in mind certain constraints — the only materials available to them are rope, string, straws, tape, rulers, bamboo skewers, clothes hangers, and rubber bands. Once each team has devised a solution and sketched their concept, they begin to test and evaluate the different components of their designs. However, despite coming up with a plan in advance, the teams find flaws in their designs. For example, one team discovers that the string they chose to use breaks when pulled. The team reevaluates their design and determines that their mistake was in choosing the wrong material. They decide that a stronger material, such as rope, would do a better job.

Identifying mistakes and proposing ways to improve upon the design is a critical part of the design process. Since modifications and improvements will help lead to the best possible product, the ability to learn from mistakes is an indispensable quality for an engineer. However, it is important to remember that the design process is not simply one of trial and error. The careful planning that went into the initial design must be carried through the entire process, from development and testing to evaluation and redesign.

To learn more about how materials are incorporated into design, check out Grass Bridge.

To learn more about the materials in a kid's invention, check out Kid Inventor: The Collapsible Lacrosse Stick.

To learn more about kids using engineering design principles, check out LEGO® Robots.

To learn more about the design process, check out What Is the Design Process?.

• In what ways do you think the materials available to the teams in the video helped or hindered them in finding a solution?
• If you could pick one other material to use for either of these designs, what would it be? Why did you select this material?
• What evidence can you find, if any, that drawing their design solution before they tried it contributed to a successful solution?
• Have you ever had a door open for you without having to touch it? How do you think this door worked? How did this door help the people who used it? Why do you think there aren't more doors like these in other places, such as in your home or your school?