Design and Build a Rube Goldberg

Designing and building is essential to engineering. Engineers follow the steps of the design process to help them create the best possible solutions to real-world problems. These challenges may be simple or complex and the wide variety of solutions can also cover a range of effort for the user. In general, complex designs require more effort to develop than simple ones. Rube Goldberg designs are meant to show the unnecessary complexities in machines, which sometimes result from modern technology.

After this activity, students should be able to:

• List the general steps of the engineering design process.
• Think critically about the importance of the machines they encounter in life.
• Use their knowledge of simple and compound machines to design and build a small Rube Goldberg machine.

In order to understand compound machines, it is helpful if students are familiar with the six individual simple machines and their abilities to make work easier, as discussed in lessons 1-3 of this unit. Compound machines are described in Lesson 4. This activity works is intended as a finale to the simple machines unit.

We have been learning about simple and compound machines, calculating mechanical advantage and thinking about machines as a part of society. What is a simple machine? A simple machine makes work easier for people. We also know that engineers build complex machines upon a foundation of knowledge of simple machines. Now we will look at how all of these things that we have been studying come together, as we take on the role of the engineers who design machines. We are not going to design just any machine though; we are going to invent Rube Goldberg machines. Recall that a Rube Goldberg is a contraption that accomplishes a simple task in a fantastically complicated way.

Several steps compose the process of inventing, regardless of the type of machine you want to create. Who knows the first step in the engineering design process? The first step in designing a good solution is to define the need and the audience. You will need to work with your team to decide what you will be designing. What is the problem you are trying to solve, and who are you designing it for?

Next, an engineer thinks about information that might help to solve the problem. Needed information might include the constraints or limitations on the problem, such as materials or time or safety. For this project, we have some materials already available and we want to use at least three simple machines. We definitely have limited time to our class period, and we want to make sure our contraption is safe.

After all of these things have been decided, engineers brainstorm design ideas. With your team, you will come up with many different simple machine ideas that could be used to accomplish your final task. Then your engineering team will choose which ones to use and create a plan or drawing of the design.

Why is it important to design your machine first, either as a drawing or a clear idea in your mind? (Answer: To just start building could lead you to a machine you don't like or doesn't work, and we don't want to waste materials and time.)

Make sure your machine has many different steps and motions in order to complete the end function and look like a Rube Goldberg. Professional engineers draw their inventions before the thing is built, so we will do that, too. Remember to include a materials list.

Once you have a drawing and materials list, and the design has been approved by the teacher, begin building. Remember that good engineers try not to use more material than necessary and are interested in an attractive product that works as designed. After everyone is finished, we will rotate through and see all the machines in action.

Before the Activity

• For Part 1, gather paper and pencils for students to draw their designs and list any additional materials.
• Gather all materials, including any additional materials requested by groups.

With the Students

Part 1: Design the Rube Goldberg Machine (25 minutes)

1. In groups of three, have student engineering teams decide on simple tasks to create machines for, intended audiences, and any information they know that will help them solve the problem.
2. With every group member contributing ideas, have students brainstorm ideas about how they will accomplish the simple task (such as getting a marble in a cup one meter away) in an overly complex way. Remind them that they must use at least three simple machines in their final designs.
3. Next, have each team collectively produce machine drawings that include dimensions.
4. Have teams include materials lists, including any special-request materials.
5. Teams show their designs and materials lists to the teacher for approval.
6. Have students make design alterations if not immediately approved. After approval, make the design more specific or the drawing more detailed as other groups finish up their designs.

Part 2: Build the Rube Goldberg (50-60 minutes)

1. Have students spend a few minutes reviewing their drawings from Part 1 before starting to build.
2. Have student teams gather their materials and begin to build their designs.

• Emphasize that each group member participates.
• Direct the students to follow the planned design as closely as possible.

3. Once teams, have completed their designs, have them test their machines. Evaluate competing design solutions to determine how well they meet the criteria and constraints of the problem.
4. Allow student teams to return to their seats and make adjustments, as necessary. Re-test any re-designs.
5. Have each engineering team display its Rube Goldberg contraptions to the class during the last 10 minutes of the period.

Pre-Activity Assessment

Discussion Questions: Solicit, integrate and summarize student responses.

• What is a Rube Goldberg? (Answer: A machine that does a simple task in a complicated way.)
• Do such machines exist in the world? (Answer: Sure, otherwise Rube Goldberg would not have made it to the dictionary. They are any wacky looking device that seems too complex for its own good; moreover, it probably does a task you don't really need done in the first place.)

Activity Embedded Assessment

Activity Discussion: Review and discuss the activity with the entire class. Use the answers to gauge students' mastery of what it means to design and build. Be sure to cover both the process and the purpose of its design.

• How does Rube Goldberg fit in to all of this? (Answer: His cartoons help us think about the meaning of machines in our society.)

Engineering Design Process: Have students acknowledge each step of the engineering design process as they are completing them. Write the steps on the board for student reference. The steps include: Define the problem, gather information, brainstorm ideas, select the most promising idea, explain your design, build and test your design, and redesign for improvement based on what you have learned from testing.

Post-Activity Assessment

Rube Goldberg Worksheet: Use this worksheet to assign students to take a closer look at a Rube Goldberg cartoon and, drawing upon previously learned concepts, develop arguments that say the machine could in fact work.

Remind students that the Rube Goldberg cartoon machines would probably never work in the real world, so they should not design something that closely resembles his cartoon, because they probably would not be able to build it.